Total Crop Management for Greenhouse Production

Transcription

1 Bulletin 363 Revised 2016 Total Crop Management for Greenhouse Production with an emphasis on Integrated Pest Management and Nutrient Management

2 Bulletin 363 Revised 2016 Total Crop Management for Greenhouse Production with an emphasis on Integrated Pest Management and Nutrient Management This publication is a joint effort of the University of Maryland, Virginia Tech and North Carolinia State University and their specialists in various environmental fields Integrated Pest Management for Commercial Horticulture University of Maryland Extension The University of Maryland, College of Agriculture and Natural Resources programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, or national origin, marital status, genetic information, or political affiliation, or gender identity and expression.

3 Authors and Publication Coordinators: Stanton A. Gill, Extension Specialist Central Maryland Research and Education Center , Co-Authors: Debby Smith-Fiola, Consultant, Landscape IPM Karen Rane, Plant Pathologist Plant Diagnostic Lab, College Park , Andrew Ristvey, Extension Specialist Wye Research and Education Center , Chuck Schuster, Extension Educator University of Maryland Extension , Joyce Latimer, Extension Specialist Virginia Tech , Not Pictured Gerald Brust, IPM Vegetable Specialist Central Maryland Research and Education Center Brian Whipker, Extension Specialist North Carolina State University , Formatting, Editing, and Image Management: Suzanne Klick, Technician University of Maryland Extension Kate Everts, Vegetable Plant Pathologist Lower Eastern Shore Research and Education Center , Will Healy, Research and Technical Services Manager Ball Horticultural Company (630) , Megan McConnell, Lab Technician Plant Diagnostic Lab, College Park, MD ii

4 Preface This manual is designed for use by growers, greenhouse managers, and Extension educators involved with the floriculture industry. Our goal with this manual is to help greenhouse growers produce the highest-quality plants with minimal loss. This publication is based on the extensive experience of Maryland greenhouse growers, independent Total Plant Management and Integrated Pest Management (TPM/ IPM) scouts, and faculty and specialists of the University of Maryland Extension. It is our intent that this manual serve as a valuable tool for improved management of greenhouse crops. We have created charts for easy access to information and text for more in-depth information on key subjects. Disclaimer Mention of trade names and products is for information only and does not constitute an endorsement or recommendation of, or discrimination against, similar products not mentioned. Printed in 2016 by University of Maryland Extension, College of Agriculture and Natural Resources, University of Maryland College Park. All rights reserved. No part of this publication may be reproduced or transmitted in any form, by any means (electronic, photocopying, recording, manual, or otherwise), without the prior written permission of University of Maryland Extension. The phone number for University of Maryland Extension is (301) Although this manual contains research-based information, and the contributors and publisher have used their best efforts in preparing this manual, the publisher and contributors offer no warranties, express or implied, with respect to the use of this manual. Manual users maintain complete responsibility for the accurate use and appropriate application of the information in this manual for their intended purpose(s). In no event shall the publisher or contributors be held responsible or liable for any indirect, direct, incidental, or consequential damages or loss of profits or any other commercial damage whatsoever resulting from or related to the use or misuse of this manual. Electronic copies of this manual are available on-line at To purchase paper copies of this manual contact or go to the website for an order form iii

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6 Table of Contents Part 1: Integrated Pest Management (IPM) for Greenhouse Operations Chapter 1 Integrated Pest Management: Scouting Overview 3 Chapter 2 Integrated Pest Management: Monitoring Crops for Key Problems 13 Chapter 3 Screening Out Insect Pests 25 Chapter 4 Disinfecting a Greenhouse: Keeping Diseases and Insects in Check 29 Chapter 5 Pesticide Application Equipment: Selection and Calibration 31 Part 2: Insect and Mite Management Chapter 6 Insecticide and Miticide Classes 37 Chapter 7 Biological Control of Greenhouse Pests 41 Chapter 8 Biopesticides and Reduced-risk Pesticides 61 Chapter 9 Understanding Insect Growth Regulators 75 Chapter 10 Impact of Selected Pesticides on Bees 79 Chapter 11 Insecticides Registered for Greenhouse Ornamentals 83 Chapter 12 Insect Control for Greenhouse Vegetable Product and Herbs 229 Part 3: Disease, Weed, and Algae Management Chapter 13 Managing Plant Diseases 241 Chapter 14 Weed and Algae Control in Commercial Greenhouses 299 Part 4: Cultural, Water, and Fertility Management Chapter 15 Plant Growth Regulators for Floricultural Crops 307 Chapter 16 Water Supply, Irrigation, and Management 335 Chapter 17 Too Wet or Too Dry? 343 Chapter 18 Precision Irrigation for Nursery and Greenhouse Crops 345 Chapter 19 Fertility Management 355 Chapter 20 Fertilizer Injection or Fertigation 369 Chapter 21 Care and Calibration of Injector Pumps 375 Part 5: Greenhouse Structures and Environment Chapter 22 Greenhouse Selection and Placement 381 Chapter 23 Greenhouse Growing Environment: Temperature and Humidity 385 Chapter 24 Greenhouse Systems Maintenance 397 Chapter 25 Greenhouse Substrates 401 Part 6: Appendix Appendix A Selected Resources 415 Appendix B Conversion Factors 418 Appendix C Images of Insects, Diseases, Abiotic Problems, and Weeds 420 v

7 List of Tables Table 1.1 Pest Problems And Indicator Plants 7 Table 1.2 Samples of Greenhouse IPM Crop Information Collection Forms 10 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops 14 Table 2.2 Key Pests of Vegetable Transplants Grown in the Greenhouse 19 Table 2.3 Monitoring Pests In The Greenhouse 22 Table 5.1 Optimum Spray Drop Sizes For Various Targets 31 Table 5.2 Theoretical Spray Coverage 32 Table 6.1 Mode of Action (MoA) Classification of Insecticides and Miticides 38 Table 7.1 Compatibility of Pesticides and Biological Control 43 Table 7.2 Biological Control of Aphids 49 Table 7.3 Biological Control of Caterpillars 50 Table 7.4 Biological Control of Fungus Gnats and Shore Flies 52 Table 7.5 Biological Control of Mealybugs 53 Table 7.6 Biological Control of Broad and Cyclamen Mites 54 Table 7.7 Biological Control of Spider Mites 54 Table 7.8 Biological Control of Scale Insects 55 Table 7.9 Biological Control of Thrips 58 Table 7.10 Biological Control of Whiteflies 60 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses 64 Table 9.1 Product Names and Distributors of Commonly Found IGRs for Greenhouse Use 75 Table 9.2 Insect Growth Regulators And The Pests They Control 76 Table 10.1 Alternatives to Neonicotinoids 81 Table 11.1 Insecticides for Aphid Control 85 Table 11.2 Insecticides for Caterpillar Control 102 Table 11.3 Nematicides for Foliar Nematode Control 115 Table 11.4 Insecticides for Fungus Gnat Control 117 Table 11.5 Insecticides for Leafminer Control 129 Table 11.6 Insecticides for Mealybug Control 142 Table 11.7 Miticides for Tarsonemid Mite Control 157 Table 11.8 Miticides for Spider Mite Control 163 Table 11.9 Insecticides for Scale Control 176 Table Insecticides for Shore Fly Control 188 Table Pesticides for Slug Control 193 Table Insecticides for Thrips Control 197 Table Insecticides for Whitefly Control 213 Table 12.1 Insecticides for Greenhouse Vegetable Production 230 Table 13.1 Products for Managing Bacterial Diseases 244 Table 13.2 Fungicides for Managing Botrytis Blight 247 Table 13.3 Fungicides for Managing Downy Mildew 253 Table 13.4 Fungicides for Managing Fungal Leaf Spots 258 Table 13.5 Fungicides for Managing Fusarium Root Rot 264 Table 13.6 Fungicides for Managing Powdery Mildew 268 Table 13.7 Fungicides for Managing Phytophthora Foliar Blight 274 Table 13.8 Fungicides for Managing Pythium and Phytophthora Root and Crown Rots 278 Table 13.9 Fungicides for Managing Rhizoctonia Root and Crown Rot 281 Table Fungicides for Managing Rusts 285 Table Fungicides for Managing Sclerotinia Blight and Crown Rot 289 Table Fungicides for Managing Thielaviopsis Root Rot 292 vi

8 Table Fungicides and Bactericides for Greenhouse Vegetable Production 295 Table 14.1 Herbicides Labeled for Use in Controlling Weeds in Greenhouses 300 Table 14.2 Algae Control With Chemicals 303 Table 15.1 Plant Growth Regulators Used To Reduce Plant Height 320 Table 15.2 Other Plant Growth Regulators Used In Production of Floricultural Crops 323 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses 325 Table 15.4 Dilution Table for Amount of Formulated Produce per Gallon of Solution 334 Table 17.1 Five Soil Moisture Levels 343 Table 17.2 Optimum Soil Moisture Levels During Plug Production 344 Table 19.1 Formulas, Molecular Masses, and Compositions of Common Macro Fertilizers 359 Table 19.2 Formulas, Molecular Masses, and Compositions of Common Micro Fertilizers 360 Table 19.3 Commercially Available Fertilizers That Either Acidify or Increase Substrate ph Based on Potential Acidity or Basicity 361 Table 19.4 Suggested Rates for Fertilizing Different Crop Types (ppm N) 363 Table 19.5 Injection Ratios And Nitrogen Concentration For Constant Feeding 364 Table 19.6 Suggestions and Precautions for Controlled Release Fertilizer Use 367 Table 21.1 Maintenance Schedule for Injector System 376 Table 25.1 Effects Of ph On Nutrient Availability In Soilless Substrates 405 Table 25.2 Intrepreting Electrical Conductivity Values From Different Methods 409 List of Figures Figure 3.1 Evaporative Cooling Pad 25 Figure 3.2 Manometers 25 Figure 3.3 Resistance Curve 26 Figure 3.4 Air Movement With Screening 26 Figure 3.5 Ventilation Air Flow 27 Figure 16.1 Irrigation Filters 339 Figure 18.1 A Schematic of a Farm-scale WSN for Precision Irrigation Scheduling 347 Figure 18.2 Different Data Collection Scenarios 349 Figure 18.3 Typical Container Moisure Dynamics Before and After Irrigation Events 350 Figure 19.1 Law Of The Minimum Principle 355 Figure 19.2 Concentration Ranges of Several Nutrients Found In Plant Leaves 356 Figure 19.3 Effects of ph on Nutrient Availability in Soilless Organic Substrates 357 Figure 20.1 Using Proportioners For Fertilizer Applications 370 Figure 20.2 Venturi Injection 371 Figure 20.3 Positive Displacement Proportioner 372 Figure 21.1 Parts of an Injector 375 Figure 21.2 Concentrate Filter 376 Figure 21.3 An EC Meter 377 Figure 23.1 Greenhouse Heating 387 Figure 23.2a HAF Fans (2) 389 Figure 23.2b HAF Fans (4) 389 Figure 23.3 Greenhouse Ventilation 390 Figure 23.4 Mechanical Greenhouse Ventilation 391 Figure 23.5a Winter Moisture Control 393 Figure 23.5b Greenhouse Air Exchange 394 Figure 23.6 Control Sensors 394 Figure 25.1 Substrate, Irrigation and Fertilizer Triangle 401 Figure 25.2 Suggested Substrate ph Ranges For Greenhouse Crops 406 vii

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10 Part 1 Integrated Pest Management (IPM) for Greenhouse Operations Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Integrated Pest Management: Scouting Overview Integrated Pest Management: Monitoring Crops for Key Problems Screening Out Insect Pests Disinfecting a Greenhouse: Keeping Diseases and Insects in Check Pesticide Application Equipment: Selection and Calibration

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12 Chapter 1 Integrated Pest Management: Scouting Overview Deborah Smith Fiola, Independent IPM Scout Stanton A. Gill, Extension Specialist Introduction Greenhouse production of bedding plants and vegetable transplants is a profitable business; nevertheless plants will be attacked by pests at some point in time. No matter how vigilant the growers, all will still face dilemmas from nutrient problems, diseases, insects, and mites. The best approach to reduce the amount of pest damage in the greenhouse is through Integrated Pest Management (IPM) methods. IPM is a scientifically proven, practical system of pest control. It includes a combination of methods that reduces pest populations by merging good horticultural practices with research-based control tactics while keeping in mind environmental safety and realistic commercial standards. Control strategies include cultural, mechanical, physical, biological, and chemical methods. Biological control includes the use of live organisms that have been commercially proven to provide acceptable levels of pest control without the use of chemical pesticides. The key to IPM is preventing problems, while being proactive once problems are found. The greenhouse should be clean prior to starting a new crop; i.e. free of old plant material, debris, and weeds. Vents and fans should be inspected and screened to prevent pests from entering. New crop plants, cuttings, or plugs coming in should be examined for pests and isolated if there is any suspicion of infection/infestation. Regular plant inspections (monitoring or scouting) are indispensable when conducted on a regular basis (weekly monitoring is suggested). Once a pest is found, pest control strategies are chosen that effectively control the target pest with limited negative impact upon the surrounding environment. Using the appropriate application equipment and applying sprays properly will improve effectiveness. Repetitive pesticide applications can be circumvented by cultural, biological, and alternative tactics (e.g., sterilizing soil, screening vents, sanitizing greenhouse areas, eliminating weeds, releasing natural enemies, and treating with insecticidal soaps/horticultural oils). If pesticides are used, they should be applied in a rotation that alternates products with different modes of action against the target pest (e.g., rotating different chemical classes). The chemical class of each pesticide is listed in this publication in order to make this process easier. Regular, systematic monitoring of the greenhouse is the backbone of a successful Integrated Pest Management (IPM) program. Insect and disease organisms can (and do) appear suddenly. Instead of reacting immediately to the pest (typically by spraying a pesticide), the IPM manager is proactive by regularly monitoring the pest population and treating only if and when necessary. Monitoring is the key to predicting and managing pest populations. Monitoring (also called scouting) is the regular inspection of plant material, as well as the surrounding benches, floors, etc., for the presence and identification of any insect, disease, cultural, abiotic, weed and nutrient problems. By inspecting the greenhouse on a systematic basis (e.g. every 7-10 days during the crop season) pests that arise can be controlled before populations become economically intolerable. Small greenhouses (<4,000 sq.ft.) can be monitored as one unit. Larger greenhouses should be divided into 2,000 to 3,000 square foot sections 3

13 for easier monitoring. IPM control decisions are all based on information gathered during monitoring. Smaller, immature pests are easier to control and can be managed with the least toxic methods. Monitoring information is used to locate and interpret all causes that directly and indirectly affect the problem (e.g. the pest, site, predators, and environment and management practices). Record Keeping The monitoring process usually begins by creating a diagram of the greenhouse which can easily be done on a computer. A formal record keeping system that is consistently used while monitoring is essential to a successful IPM program. Many scouts create maps that chart the location of benches, fans, entry areas, and irrigation hoses. A new map is used for each crop cycle. Monitoring forms (or datasheets) are used to quickly record monitoring information, particularly on a large-scale basis. Monitoring forms used by professional IPM scouts in Maryland can be spreadsheets, check-off lists, or charts (Table 1.2). Forms can be very simple or quite detailed, and should be personally modified for ease of use and evaluation. The goal is to set up a clear, concise way of recording and communicating all plant and pest monitoring information so growers can make informed decisions. The datasheet ultimately needs to record what, where, and how many pests (as well as beneficial insects) are present. Consistent and detailed record keeping is very important not only to improve overall control tactics, but to ultimately document the success of the program. Datasheets can be easily compared to one another over time. It is important that all records have the same standard format since they can only be compared if they uniformly and consistently report the same facts. The base map/datasheet should include some background information, including the history of each crop, particularly that of past pest problems and exactly where the problems occurred. Mark greenhouse drainage patterns, as well as the sun/shade patterns and any applications of fertilizer and other materials. For each monitoring visit, the date, temperature, and humidity levels are recorded. The bulk of the datasheet is then used to record any pests or disorders found, where and when they were found, what was done, and any pertinent issues such as temperature inversions, residues, etc.. Specific information to include on the form/datasheet: (Use a scale of 1-10 for levels): Date(s) of monitoring Minimum and maximum temperatures for each day Growing medium ph and soluble salts of plants in growing blocks Specific crop observation (height, leaf color, bud development, etc.) Visual health/appearance level of the plant Root health based on weekly check of random plants Specific pest/problem encountered and life stage Exact location of the pest Counts of pests on the plants, including stage of growth (egg, immature, adult) Insect or disease severity level (or counts of pest population levels) Presence/absence of beneficial organisms and competitors that are naturally occurring or released Results of control tactics Insect counts from sticky cards (change cards weekly) Notes on unusual weather patterns, any existing damage, or predisposing pest factors can be included or recorded in a comments column. Predictive information may also be included, such as an insect or disease appearance timetable and susceptibility of certain cultivars or plant species. Most charts rate the severity of the infestation using either a rating system of 1 to 10, or a rating check-off system of low-moderatehigh levels present. It is also helpful to estimate the percentage of bench area damaged. The area of pest 4

14 infestation on the map can then be either highlighted to document the location or color coded to indicate specific pests. Carry the datasheet (or pocket PC) throughout each monitoring visit, recording monitoring notes directly. When a control tactic is initiated, note exactly when, where, and what was done. During the next monitoring visit, inspect and comment on the success of the control. Proper monitoring should identify specific areas within a crop where pests are absent or where pests are present at levels well below those necessary to cause damage, thus preventing unnecessary control applications and expenditures. By determining the focal point of an infestation early, a few plants can be either spot treated or rogued by placing them in a plastic bag before removal. The rest of the crop can be then be treated more effectively. Weekly summaries of all monitoring observations should be recorded and the information should be itemized for each greenhouse, according to the pests detected, the counts, and any unusual circumstances found in the greenhouse. As the season progresses and pest trends develop, a direction for pest management decisions will become apparent. Spray records are also important. State and federal regulations require growers to maintain detailed and upto-date pesticide application records. Monitoring records should also include spray information, including the date and time of application, areas treated, name of the pest, pesticide used, rate and amount applied, method of application, time required to apply the pesticide, and effectiveness. Recording the fertilizer analysis, rate applied (PPM), and frequency will also provide a valuable guide for future growing. It is important for the scout to have access to fertilization and irrigation application records in order to make more appropriate recommendations regarding the fertility of the crop. The best way to access this information is for the greenhouse grower or employee to post a chalkboard, clipboard, or data sheet to fill out with all the necessary pesticide application, irrigation, and fertilization information -- as well as minimum and maximum temperatures. Scouting equipment IPM scouts often use a backpack to carry monitoring equipment with them as they scout a greenhouse. A hand lens is the most useful tool used to detect live insects and disease symptoms. Scouts should wear clothing that is not attractive to insects to avoid inadvertently carrying insect pests into the greenhouse (e.g. shades of yellow and blue can attract thrips, whiteflies or other pests). Some equipment suggestions include: Hand lens (preferably 16x) Pruners (for taking plant samples) Plastic bags (for taking plant samples) Pocket microscope Beating tray Flags/flagging tape to identify problem areas or for height control Ruler (to measure plant height) Vials with rubbing alcohol (to collect small insect samples for identification) Apron (extra) Sticky cards (or other traps for monitoring flying insect populations) Gloves Waterproof permanent marker, pencil Plastic spoons and small paper cups/bags (for taking soil samples) Plastic bag for sample collection 5

15 Small digital camera (that can take good close-up images) Conductivity and ph meters Resource information (small books with photographs of key pests, pesticide labels) Soil thermometer On-site diagnostic test kits Smart phone (camera, note-taking, pesticide labels, references) Monitoring Plan Monitoring must be done in a thorough manner to be successful. The number of plants, their size, and the location of the benches will all influence the time and pattern needed to monitor. Start by following a route or pattern that will cover all areas of the greenhouse. Try to always begin from a major doorway, since this area is typically where pest problems commence. Scouts should aim to walk down every aisle and move from bench to bench in a zig-zag pattern. Choose individual plants at random; inspections should include checking for insects, mites, or disease symptoms. Spend at least 10 minutes inspecting 20 or more plants from every 1,000 square feet of production area. At least three plants on every bench should be inspected from the edge, the middle and as far into the bench as can be reached. Any plants that visibly appear discolored or dissimilar should be inspected more closely. Inspection starts by looking for deviations from normal crop growth, height and color. Pick up each plant and visually examine it beginning at the soil line. Scan the whole plant, inspecting the stem and undersides of the lower leaves for discoloration, signs or symptoms of pests, and indications of nutrient disorders. Look first at lower, older leaves, then the upper, younger leaves and finally, the new tip growth. Pay special attention to tip growth, buds and blooms. Because insects and some diseases are found on the underside of a leaf, it is important to turn the leaves over to check for pests. Invert and remove the pot to examine the roots. Pay special attention to plants on the outside rows of benches. Remember to also inspect hanging baskets. Keep in mind that most pests are not distributed evenly throughout the crop. It is therefore very important to check all the leaves on the plant, especially when the crop is young. Never assume to know exactly where the pests are located (Table 2.3). Once an infestation is detected, monitoring should occur more frequently. The customary monitoring route should also change at this point. Using scouting records, monitor the least infested areas first and the most heavily infested areas last. This approach will help prevent the spread of any pests from an infected area to a new area. Likewise, examine stock plants before inspecting cuttings in order to reduce the possibility of infesting the stock plants. Indicator Plants Indicator plants are highly susceptible host plants (Table 1.1). They are often grown purposely, either among the commercial crop or at the edge of the crop/benches. Since these indicator plants are the first plants to become infested/infected, the scout knows that the adjacent main crop may be attacked soon. Indicator plants therefore aid in predicting pest problems. Indicator plants are marked with a stake or flagging tape so they can be easily located and examined repeatedly to study pest establishment. Rechecking the same plant gives the scout an opportunity to closely examine an ongoing pest population -- or symptoms before they spread to surrounding plants. Tracking pest establishment rates provides information regarding the rate at which the pest s life cycle is developing, as well as the best time to apply pest control measures. Indicator plants can also be used to check if control treatments are effective. 6

16 Table 1.1 Pest Problems and Indicator Plants Pest Problem Aphids Impatiens Nectoric Spot Virus Spider Mites Thrips Whiteflies Indicator Plants Sweet peppers and fuschias Fava beans, petunias, impatiens Marigolds and roses Marigolds, dracaena spikes, verbena, petunias and impatiens Tomato, lantana, gerbera daisy, poinsettia, and eggplant For example, peppers and eggplants are prone to aphid and thrips infestations. Therefore, if peppers are purposely grown near susceptible bedding plants, they will be the first to be attacked by these pests. In this way, they will also indicate that an early thrips population is present in the greenhouse. The best indicator plants to detect the presence of thrips carrying both Impatiens Necrotic Spot Virus and Tomato Spotted Wilt Virus are fava beans and certain cultivars of petunia. These plants will develop viral symptoms within one week if fed on by the infected thrips. The following steps are recommended when using petunias and fava beans as indicator plants: Remove flowers from indicator plants to encourage feeding on foliage where symptoms can be observed. Place a blue non-sticky card in each pot at plant height. The blue card will attract thrips to the indicator plant. Blue plastic picnic plates also work well. Plant 1-2 fava bean seeds per 4-inch pot and place them at 12 pots per 1,000 ft 2. Remove fava beans plants if symptoms are observed because the virus is systemic in these plants. Viral symptoms appear as dark brown angular lesions on leaves or yellow to light green ring spots. Dark necrotic areas can also be seen on the stem. Fava beans have dark black spots on their stipules that should not be confused with viral symptoms. Traps A monitoring program includes utilizing sticky cards to determine initial pest levels as well as pest population trends. Sticky cards attract insect pests which become stuck on the sticky coating of the trap. The traps come in two colors, either a bright yellow or a medium blue. The yellow traps attract flying aphids, fungus gnats, whiteflies, leafminers, thrips, and other insects. Blue sticky traps are used primarily to attract thrips. Sticky cards are placed in a grid pattern approximately every 1,000 square feet. They are positioned just above the plant canopy from 4 inches to 16 inches above the top foliage. One way to easily position sticky cards is to attach each card vertically to a bamboo stake with a clothespin. As the crop grows, cards can be moved up. Place additional sticky cards near all entryways and vents. Designate the location of each sticky card on the greenhouse datasheet. Check the sticky cards every scouting visit (twice a week if possible). Record the total number of whiteflies, thrips, fungus gnats, winged aphids, and shore flies from each card on the field data sheet. Use a hand lens to identify insects found on the sticky traps. When handling the sticky traps, it helps to wear gloves or have some waterless hand cleaner nearby. The time spent counting insects on sticky traps can be reduced by counting the insects within a one inch wide vertical column on the trap. Since insects are not distributed evenly horizontally across the trap, columns counted should be vertical towards the middle of the trap. For example, aphids and thrips tend to be 7

17 caught on the bottom half of the traps, while leafminers are caught more often along the top half. Wasps and whiteflies, on the other hand, have a tendency to be spread uniformly throughout the trap. Aphids tend to be caught in the middle vertical columns. Setting Thresholds and Timing Actions in the Greenhouse A certain number of insects, mites, and other pests can be tolerated on greenhouse crops. The degree of tolerance depends on many factors, including the stage of growth in the plant cycle, the plant species, the amount of time until market, and the intended market audience. For example, if the market audience is parents of horticulture students growing the plants, tolerance for the presence of insects may be high, especially if students can reassure parents that these pests will not noticeably harm the plant. However, most people have very low thresholds if they are paying for plants. A University of Maryland study showed that garden center customers could discern that a plant was injured at a mere 5% injury level. In general, as the time of marketing a crop for the general public grows nearer, tolerance for obvious pest presence grows very low. Few, if any, action thresholds have been published for pest levels on greenhouse crops. For some pests and diseases the threshold is relatively easy: no tolerance at all. One example is the western flower thrips (WFT) and the tospovirus that causes Impatiens Necrotic Spot Virus (INSV). The tolerance level for the disease and for its insect vector, WFT, is near zero because once this disease and its vector are established in a greenhouse, many or all of the plants can potentially be destroyed. The large number of species and cultivars grown in the greenhouse makes it difficult to set specific thresholds. Goals of the end user also influence the choice of threshold levels. For example, flower thrips cause a small amount of stippling damage to foliage and flowers that most customers would not notice. A greenhouse manager may tolerate a number of flower thrips on plants leaving the greenhouse if the customer is a plant- and insect-savvy consumer. Since flower thrips are not vectors of INSV, as the western flower thrips are, growers can be more tolerant of populations of the former on most flowering bedding plants. However, if the crop is to be sold to a garden center (where the plants may be held for a week or more and then sold to the general public), the flower thrips may become noticeable on the flowers and foliage, which could deter sales for the garden center. How can the threshold level be determined that prompts some sort of action? It is suggested to closely monitor one plant species at a time and follow that crop for an entire growing cycle, taking judicious records to determine what pests you noted on the plants (and when) during the season. Note at what population levels damage begins to be detected on the plants. This data, collected over several crop cycles, will help with pest control decisions such as when the insect population is no longer tolerable or when it is time to start treatment. Knowing the susceptibility of common greenhouse crops to specific insects and mites can help identify which plants to monitor closely for potential insect or mite activity. Monitoring efforts can therefore be focused upon the plants with apparent pest problems, and pests can accordingly be predicted for future monitoring. When using biological control, start treatment at the first detection of the pest in the greenhouse. Using biological control with low threshold levels is the most effective way to approach pest management in a greenhouse. If chemical control is used, start treatments when populations are visible and a small amount of damage is detected. If that point occurs well before market time, foliar sprays can be applied to many pests to ensure that most minor pest populations are reduced by a well-directed spray. Yellow sticky cards can also be used to set insect thresholds. For example, sticky cards can be used to attract fungus gnat adults in a pansy crop. Since pansies are highly susceptible to damage from fungus gnat larvae, card counts of adult fungus gnats can indicate a growing problem in the crop. If large numbers of fungus 8

18 gnat adults are detected early in the crop cycle a grower may decide that adult activity indicates egg laying by adult females, which in turn will result in high larval populations in the crops root system. Therefore, treat when adult levels on sticky cards are high (50 or more per 7-day period). IPM Decision Making Each week, summarize all generated monitoring information in order to make control decisions. The monitoring records will also indicate whether or not control measures were successful or if they need to be repeated. Before deciding upon a control tactic, make absolutely sure of the identity of the target pest present. Accurate diagnosis is the key to management, regardless of the specific control choice. Many pesticides and most natural enemies are often specific to just one pest or group of pests. If you are having trouble diagnosing a problem, contact your Extension Educator or Extension Specialist. If you suspect a disease, determine if you can identify the causal agent or take a plant sample for further diagnosis and testing to the University diagnostic lab in your state (Appendix A). Entire plants are the best samples to send to a lab for diagnosis. Fasten a plastic bag around the root ball and wrap the entire plant in dry newspaper or paper towels. Include information on severity of the problem, timing of symptom development and pesticides applied. Use submission forms developed by the diagnostic lab when available. Send samples showing a range of symptoms. Use the following questions to help make the necessary treatment decisions: Is the population increasing, decreasing, or remaining the same? Is it absolutely necessary to spray to prevent unwanted damage? Are insects migrating from weeds under the benches to your crops? Is the treatment from last week working? At the end of each week, the scout should review the monitoring information with the greenhouse owner/ grower. Use the summary records (numbers of pests recorded from sticky card counts and foliar inspections, any resulting pest population trends, and the use of indicator plants and located reservoirs of pests) to determine the pest management strategy. Summary Monitoring ensures the early detection of pests, which in turn results in better pest management. When problems are detected early, there will be better pesticide coverage due to a smaller plant canopy. Problem crops and problem areas within a crop can be identified and spot treated which reduces the need for blanket pesticide applications. In addition, bio-pesticides and natural enemies (biological control organisms) tend to be more successful on immature or low level pest populations. 9

19 Table 1.2 Samples of Greenhouse IPM Crop Information Collection Forms The following are sample templates that can be used to record scouting data. When developing a form, be sure to include the date, reporting person (if an additional scout is hired) and the greenhouse. Different areas within a greenhouse can be identified as Greenhouse Management Units (GMU). Examples include Greenhouse Area 1 (left side), Greenhouse Area 2 (back), and Greenhouse Area 3 (front). Be sure to make a map of each greenhouse to be able to track the progress of each crop and insect, disease and cultural problems. Crop Information Form: Plant Species Number of Plants or Containers Planting Date Expected Harvest Date Fertility Information Form: Application Date Applicator Plants or Areas Treated Fertilizer Source Applicaton Rate (PPM) Comments Insect Control Information Form: Date Applied Greenhouse Designation Product Applied Applicator Application Rate Evaluation Comments Evaluation Method (Card count decrease or reduction of pests on plants) 10

20 Disease Control Information Form: Date Applied Greenhouse Designation Product Applied Applicator Application Rate Evaluation Comments Evaluation Method (Card count decrease or reduction of pests on plants) Weed Control Information Form: Application Date Greenhouse Designation (or outdoors) Applicator Product Applied Application Rate Electroconductivity (EC) and ph Levels Form: Date: Plant Species EC Levels ph Levels Reasons For Testing Note ph and EC testing method (i.e. 1 = saturated pest method or 2 - PourThru Method Root Health Form: Date: Location Plant Rating (good, fair, poor) Comments 11

21 Insect and Mite Activity Form: Sticky Card Counts Date: Location Card Number Whitefly Count per Card Thrips Count per Card Fungus Gnat Count per Card Shorefly Count per Card Winged Aphid Count per Card Insect and Mite Activity Form: Whole Plant Counts Date: Location Plant Numbers of Plant Sampled Pest Number of Pests Found per Plant Average Number of Pests Found Increase or Decrease from Previous Count Plant Damage Noted (%) Disease Activity Form: Date: Location Plant Disease Increase or Decrease in Severity Plant Damage (%) 12

22 Chapter 2 Integrated Pest Management: Monitoring Crops for Key Problems Deborah Smith Fiola, Independent IPM Scout Stanton A. Gill, Extension Specialist Kate Everts, Vegetable Plant Pathologist Introduction Bedding plants and vegetable transplants may only be in the greenhouse for a short period of time, yet still must be kept pest-free and of high quality. A challenge when growing vegetable transplants is that there are few pesticides labeled for them. There is only one plant growth regulator, Sumagic, labeled for fruiting vegetables. Most pesticides labeled for ornamental greenhouse bedding plants are not labeled for vegetable bedding plants. Integrated pest management (IPM) tactics offer the most practical way to effectively manage pests on vegetable transplants and ornamental bedding plants. Growers can improve bedding plant production while minimizing their reliance on routine pesticide applications through the use of regular monitoring of fertility and ph levels, root health and insect and disease problems. The utilization of many different management options (cultural, physical, mechanical, biological and chemical) is the best way to minimize both pest problems and pesticide use and costs. Knowing the cultural requirements and likely pests of each crop will help with the monitoring process and diagnosing problems (Tables 2.1 and 2.2). Pay particular attention to scheduling times, light, temperature, and nutritional requirements in order to grow healthy crops. The key to an effective program is monitoring, early detection, proper identification, and early intervention. 13

23 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops Key to Levels of Fertilization: *Light fertilization SME and PourThru EC of 0.25 to 0.50 ms/cm; **Medium fertilization SME and PourThru EC of 0.50 to 1.5 ms/cm; ***Heavy fertilization SME and PourThru EC of 1.50 to 2.5 ms/cm. Plant (Common name/ Latin name) African Violet Saintpaulia ionantha Ageratum Ageratum houstonianum Azalea Rhododendron obtusum R. simsii Bacopa Sutera cordata Begonia Begonia x semperflorens cultorum (Begonia tuberhybrida) (Begonia socotrana x B. tuberhybrida) Black-eyed Susan vine Thunbergia alatus Bougainvillea Bougainvillea spp. Browallia Browallia speciosa Calla lily Zantedeschia sp. Carnation Dianthus caryophyllus Major Pests; Insects, Mites, Arthropods, Mollusks Cyclamen mite, mealybugs, whiteflies Major Diseases Botrytis, Phytophthora blight, foliar nematode, powdery mildew, Pythium root rot, Rhizoctonia stem/ crown rot, tospovirus Cultural Comments Very sensitive to cold. Water must be room temperature or injury that resembles a virus or leaf spot disease can occur. Ammonium toxicity can cause leaf yellowing. ph: Light fertilization* Aphids, whiteflies None serious Leave seed exposed to light during germination. Light fertilization* Lace bugs Foliar nematode, Cylindrocladium blight, root rot, Phytophthora root and crown rot Sensitive to salt Light fertilization* Spider mites None serious Use well-drained mix. Broad mites, fungus gnats, thrips Spider mites, whitefly, aphids, leafminer Aphids, mites Bacterial leaf spot, crown gall, cucumber mosaic virus, tospovirus, foliar nematode, powdery mildew, root rots ph: Light fertilization* Rhizoctonia, Pythium root rot ph: Medium fertilization** Medium fertilization** Aphids, mites Tospovirus ph: Medium fertilization** Aphids, spider mites, Virus, bacterial soft rot of Light fertilization* thrips rhizomes Fungal leaf spots ph: Medium fertilization** 14

24 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops (continued) Plant (Common name/ Latin name) Celosia Celosia cristata C. plumosus C. spicata Chrysanthemum, Florists Dendranthema grandiflora Cineraria Pericallis x hybrida Coleus Solenostemon scutellarioides Major Pests; Insects, Mites, Arthropods, Mollusks Aphids Aphids, thrips Aphids Aphids, slugs, whiteflies, mealybugs Major Diseases Rhizoctonia damping-off, bacterial leaf spot Pythium root and stem rot, tospovirus, Botrytis, bacterial leaf spots, fungal leaf spots, Fusarium wilt, foliar nematode Tospovirus, Botrytis, Rhizoctonia and Pythium damping-off Tospovirus, downy mildew, Rhizoctonia root rot/blight, Botrytis Cultural Comments Sensitive to cold and to salt Light fertilization* Requires high nitrogen levels ph: Light fertilization* Light fertilization* Very sensitive to salt Light fertilization* Cyclamen Cyclamen persicum Dahlia Dahlia x hybrida Daisy, sunscape Osteospermum Dusty miller Senecio Flowering tobacco Nicotiana Fuchsia Fuchsia x hybrida Gardenia Gardenia jasminoides Gazania Gazania Gerbera daisy Gerbera jamesonii Fungus gnats, thrips, cyclamen mites Aphids Tospovirus, Rhizoctonia root rot, Fusarium corm rot/wilt, bacterial soft rot of corms, Botrytis Tospovirus, root knot nematode, foliar nematode, Botrytis, Pythium, and Rhizoctonia stem/root/cutting rot, other viruses ph: Light fertilization* Medium fertilization** Thrips None serious ph: Medium fertilization** Aphids None serious Medium fertilization** Whiteflies Whiteflies Aphids, mealybugs, spider mites TMV, other viruses, damping off Botrytis, tospovirus, black root rot, rust Botrytis Expose seed to light during germination. Medium fertilization** Light fertilization* Overwatering or temperature swings can cause bud drop Light fertilization* Thrips None serious ph: Mediium fertilization** Aphids, thrips Tospovirus, powdery mildew ph: Light fertilization* 15

25 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops (continued) Plant (Common name/ Latin name) Gloxinia Sinningia speciosa Hibiscus Hibiscus rosa-sinensis Hydrangea Hydrangea macrophylla Impatiens Impatiens wallerana Ivy geranium Pelargonium peltatum Lantana Lantana camara Lilies (Asiatic and Oriental) Lilium hybrids and Easter lily Lilium longiflorum Lobelia Lobelia erinus Marigolds Tagetes New Guinea impatiens Impatiens x hawkeri Pansy Viola x wittrockiana Major Pests; Insects, Mites, Arthropods, Mollusks Aphids, fungus gnats, thrips Aphids, mealybugs, spider mites, whiteflies Major Diseases Tospovirus, Botrytis, Phytophthora crown rot Bacterial leaf spots, fungal leaf spots, foliar nematode Cultural Comments ph: Light fertilization* Medium fertilization** Whiteflies Powdery mildew, virus Medium fertilization** Aphids, fungus gnats, thrips Fungus gnats Pythium root rot, Rhizoctonia root rot, tospovirus; If plugs come in with leaf spots (bacterial or fungal) it can be troublesome; otherwise leaf spots are uncommon. Botrytis, bacterial blight (Xanthomonas). May be a symptom-free host for bacterial blight: never grow near zonal geranium. Light fertilization* Oedema, salt sensitive Light fertilization* Thrips, whiteflies Foliar nematode ph: Heavy fertilization*** Aphids, fungus gnats, Viruses, Botrytis, Pythium ph: thrips root rot, Rhizoctonia root rot Medium fertilization** Spider mites, thrips Tospovirus Medium fertilization** Aphids, whiteflies Broad mites, fungus gnats, thrips Aphids, variegated fritillary caterpillar, whiteflies Botrytis, fungal leaf spots, white mold (Sclerotinia), Rhizoctonia web blight Tospovirus, Pythium root rot, Rhizoctonia root rot/blight Myrothecium leaf blight. Black root rot, Pythium root rot, Rhizoctonia blight, fungal leaf spots, anthracnose (Colletotrichum), Botrytis Some varieties very sensitive to air pollution. ph: Light fertilization* ph: Light fertilization* ph: Light fertilization* 16

26 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops (continued) Plant (Common name/ Latin name) Periwinkle Vinca minor, V. major Periwinkle, Madagascar Catharanthus roseus Petunia Petunia x hybrida and other species Phlox Phlox drummondii Poinsettia Euphorbia pulcherrima Primrose Primula acaulis Regal geranium Pelargonium x domesticum Salvia Salvia splendens S. farinacea Salvia x superba Scaevola Scaevola aemula Snapdragon Antirrhinum majus Stock Matthiola incana Major Pests; Insects, Mites, Arthropods, Mollusks Thrips Green peach aphids Aphids, thrips Aphids Fungus gnats, Lewis mite, mealybugs, twospotted spider mites, Whiteflies Thrips, whiteflies Thrips, whiteflies Whiteflies, green peach aphids, melon aphids Aphids, thrips Aphids Major Diseases Tospovirus, Phomopsis blight (V. minor) Tospovirus, other viruses, black root rot, Pythium root rot, Phytophthora crown rot Tobacco mosaic virus, tospovirus, other viruses, Rhizoctonia damping-off, black root rot, Botrytis Botrytis, fungal leaf spots, foliar nematode, stem and bulb nematode (Ditylenchus), powdery mildew, viruses Botrytis, Pythium root rot, Rhizoctonia, poinsettia scab Tospovirus, other viruses, Botrytis, fungal leaf spots Virus, Botrytis. May be a symptom-free host for bacterial blight: never grow near zonal geraniums. Pythium and Rhizoctonia damping-off, tospovirus, downy mildew Cultural Comments Can be a hidden host for tospovirus because symptoms can be inconspicuous. ph: Very sensitive to cold. Minimum temperature: 60 F Some varieties sensitive to ozone. ph: Medium fertilization** Fertilization is cultivar dependent. Light fertilization* ph: Medium fertilization** ph: ppm based on nitrogen Light fertilization* TMV, Pythium root rot ph: Medium fertilization** Tospovirus, Pythium root rot, Chill seeds for several downy mildew, rust days before sowing to improve germination. ph: ppm based on nitrogen and potassium Light fertilization* Rhizoctonia root Light fertilization* rot, black root rot 17

27 Table 2.1 Key Pests and Cultural Requirements of Greenhouse Ornamental Crops (continued) Plant (Common name/ Latin name) Sweet alyssum Lobularia maritima Sweet William Dianthus chinensis Verbena Verbena x hybrida Zinnia Zinnia elegans Zonal geranium Pelargonium x hortorum Major Pests; Insects, Mites, Arthropods, Mollusks Major Diseases Cultural Comments Aphids Rhizoctonia root rot ph: Needs light for germination Aphids Anthracnose, fungal leaf ph: spots, Pythium root rot Medium fertilization** Whiteflies, thrips Aphids Aphids, cyclamen mites Rhizoctonia damping-off, black root rot, powdery mildew, Botrytis, viruses Bacterial leaf spot (Xanthomonas), powdery mildew, Botrytis, Alternaria leaf spot, Rhizoctonia damping-off, tospovirus Pythium and Rhizoctonia root rot/cutting rots, black root rot, bacterial blight (Xanthomonas), rust (Puccinia pelargoniizonalis), Botrytis Seed can be difficult to germinate. Medium fertilization** Very sensitive to cold: Minimum soil temperature for germination: 70 F Obtain clean seed: bacterial leaf spot and Alternaria can be in the seed. Light fertilization* Oedema ph: Light fertilization* 18

28 Table 2.2 Key Pests of Vegetable Transplants Grown In The Greenhouse Key to Levels of Fertilization: *Light fertilization SME and PourThru EC of 0.25 to 0.50 ms/cm **Medium fertilization SME and PourThru EC of 0.50 to 1.5 ms/cm ***Heavy fertilization SME and PourThru EC of 1.50 to 2.5 ms/cm Plant (Common name/latin name) Broccoli Brassica oleracea Brussels sprouts Brassica oleracea Cabbage Brassica oleracea Cantaloupe Cucumis melo CauliBroccoli Brassica oleracea Cauliflower Brassica oleracea Chives, common Allium schoenoprasum Collards Brassica oleracea Major Pests; Insects, Mites, Arthropods, Mollusks Aphids, caterpillars Aphids, caterpillars Cabbage-root fly, slugs, caterpillars Aphids, mites, whiteflies Aphids Aphids, caterpillars Aphids Caterpillars 19 Major Diseases Rhizoctonia root rot, bacterial black rot Rhizoctonia root rot, bacterial black rot Rhizoctonia root rot, Xanthomonas (black root rot) Pythium dampingoff, leaf spotting from bacterial fruit blotch, watermelon fruit blotch Rhizoctonia root rot, bacterial black rot Rhizoctonia root rot and damping-off, bacterial black rot Rhizoctonia root rot and damping-off Rhizoctonia root rot, bacterial black rot, downy mildew Cultural Comments Obtain clean seed because bacterial black rot is seed-borne. Light fertilization* Obtain clean seed because bacterial black rot is seed-borne. Light fertilization* Obtain clean seed because bacterial black rot is seed-borne. Light fertilization* Include micronutrients. Susceptible to sunscald when removed from greenhouse and transplanted outside. Sensitive to cold. Minimum night temperature: 60 F. Light fertilization* Obtain clean seed because bacterial black rot is seed-borne. Light fertilization* Obtain clean seed because bacterial black rot is seed-borne. Medium fertilization** Include boron in fertilizer. Light fertilization* Obtain clean seed because bacterial black rot is seed-borne. Light fertilization with micronutrients*

29 Table 2.2 Key Pests of Vegetable Transplants Grown In The Greenhouse (continued) Plant (Common name/latin name) Cucumber Cucumis sativus Eggplant Solanum melongena Endive Cichorium endivia Escarole Cichorium endivia Kale Brassica oleracea Kolrabi Brassica oleracea Lettuce Lactuca sativa Okra Abelmoschus esculentus Onions Allium cepa Parsley Petroselinum crispum Peppers Capsicum spp. Major Pests; Insects, Mites, Arthropods, Mollusks Slugs and snails, spider mites Aphids Aphids, slugs Major Diseases Rhizoctonia root rot and damping-off, leaf/ cotyledon spot from bacterial fruit blotch Pythium and Rhizoctonia root rots and dampingoff; stunting and leaf spot from tospovirus Pythium and Rhizoctonia root rot and damping-off Cultural Comments Sensitive to cold (min. night temperature is 60 F). Susceptible to sunscald when removed from greenhouse and transplanted outside. Very sensitive to cold. Injury occurs below 40 F. Minimum night temperature: 60 F. Light fertilization* Slugs Pythium root rot Light fertilization* Caterpillars, slugs Caterpillars Root aphids, aphids on foliage, slugs Onion fly Aphids, spider mites, thrips Rhizoctonia root rot, bacterial black rot, downy mildew Rhizoctonia root rot, bacterial black rot, downy mildew Pythium and Rhizoctonia damping-off; tospovirus Rhizoctonia and Pythium root rot and damping-off, tospovirus Rhizoctonia damping-off Pythium root rot, Rhizoctonia root rot and damping-off Pythium root rot, Rhizoctonia root rot and damping-off Leaf spot mosaic from tospovirus and other viruses; stunting, leaf distortions, and mosaic from tobacco mosaic virus (TMV); bacterial leaf spots; Phytophthora root rot and wilt Obtain clean seed because bacterial black rot is seed-borne. Obtain clean seed: bacterial black rot is seed-borne. Light fertilization with micronutrients* Tospovirus causes leaf spot and stunting Light fertilization* Difficult to germinate; need to scarify seed. Pre-germinate Light fertilization* 20

30 Table 2.2 Key Pests of Vegetable Transplants Grown In The Greenhouse (continued) Plant (Common name/latin name) Pumpkins Cucurbita spp. Spinach Spinacia oleracae Squash Cucurbita spp. Tomato Lycopersicon spp. Watermelon Citrullus vulgaris Major Pests; Insects, Mites, Arthropods, Mollusks Aphids, thrips Leaf miner, slugs Slugs, black bean aphids, aphids Aphids, mites, thrips, whiteflies Spider mites, whiteflies Major Diseases Pythium root rot and damping-off, downy mildew Pythium and Rhizoctonia root rot damping-off, white rust, downy mildew Pythium and Rhizoctonia damping-off Bacterial spot; bacterial canker; Bacterial spot; bacterial canker; bacterial speck; Septoria leaf spot; damping-off from Pythium; Rhizoctonia stem canker from Sclerotinia; sclerotiorum (timber rot); Botrytis; tospovirus-causing leaf spot and stunting; tobacco mosaic virus causing distortions, mosaic, and stunting; damping-off from Pythium and Rhizoctonia; Cotyledon and leaf spot from bacterial fruit blotch; Alternaria solani Cultural Comments Light fertilization* Light fertilization* Sensitive to cold Light fertilization* Very sensitive to herbicide drift, especially from 2,4-D, applied near greenhouse. Obtain clean seed: many bacterial and fungal diseases may be seed-borne. Medium fertilization** Sensitive to cold. Light fertilization* 21

31 Table 2.3 Monitoring For Pests In The Greenhouse Pest Aphids (general) Aphid, Chrysanthemum (Macrosiphoniella sanborni) Aphid, Green peach (Myzus persicae) May damage plants through disease transmissions as well as from feeding Aphid, Melon (Aphis gossypii) Caterpillars (general) Best Monitoring Method Yellow sticky cards to indicate aphid migration into greenhouses in spring, summer, and fall. Inspect plant foliage weekly. Presence of cast skins and/or honeydew is a good indicator of aphids. Found only on chrysanthemum species. Inspect plant foliage weekly. Found on wide range of perennials. Prefer new growth. Found on a wide range of perennials. Several species feed on greenhouse crops. Most adult butterflies and moths overwinter outdoors and migrate into greenhouses in the fall. Regular monitoring of adult flight activity alerts growers when to look for eggs laid on foliage or stems. Identification Features Each species differs in size, color, location on plant, and crop preference. Most aphids are 1 4 mm in size, pear-shaped and soft bodied with 2 cornicles (tailpipes) at rear of abdomen. Legs and antennae are typically long and slender. Winged forms found on cards; wingless forms found on plants. Shiny, reddish-brown to blackish-brown. Cornicles are short, stout, and black. No indentation between antennae. Range in color from light green, light yellow, green, gray-green, pink to reddish. Pronounced indentation between antennae on front of head. Cornicles are long, thin, and slightly swollen in the middle. Tip of cornicles are dark and slightly flared. Color varies from light yellow to dark green. No indentation between antennae. Distinct cornicles always dark in color for entire length. Most caterpillars have appendages, called prolegs, on abdomen. All have mouthparts for chewing foliage and stems or boring into stems. Potential Biological Control Green lacewings (Chrysoperla carnea and Chrysoperla rufilabris), Aphid midge (Aphidoletes aphidimyza), Parasitic wasp (Aphidius colemani) Entomopathogenic fungus (Beauveria bassiana - Naturalis-O and BotaniGard). See aphid section above. See aphid section above. See aphid section above. Microscreening over vents and greenhouse openings excludes migrating adult moths and butterflies. Several species of moths and butterflies are susceptible to applications of Bacillus thuringiensis kurstaki (Bt) in early caterpillar stages. Bt is sold under several brand names. 22

32 Table 2.3 Monitoring For Pests In The Greenhouse (continued) Pest Fungus gnats Bradysia spp. Leafhoppers Thrips Chilli thrips (Scirtothrips dorsalis) Flower thrips (Frankliniellla tritici) Onion thrips (Thrips tabaci) Western flower thrips (WFT) (Frankliniella occidentalis) Best Monitoring Method Sticky cards will capture adults. Lay potato slices (1" by 1") on soil surfaces; larvae will migrate to potato disk surface facing soil. Sticky cards will occasionally capture adults. In outdoor beds, sweep nets can sometimes capture adults. Adults congregate in open flowers and can be easily tapped or blown out of flowers. Many thrips species, especially WFTs, are found in tight, hidden parts of plants; others such as flower thrips feed on open leaf surfaces. Feeding thrips deposit minute black fecal spots in circular shapes on leaf surfaces. Yellow sticky cards capture thrips, but blue sticky cards are more attractive to WFT. Identification Features Adults are small, humpbacked flies with long legs, beaded antennae, and a single pair of wings with characteristic forked vein near wing tips. Larvae are opaque to white with black head capsule. Small, slender insects that disperse rapidly when disturbed. Both adults and nymphs run sideways and are good jumpers. Most are wedge-shaped and vary in color: shades of green, yellow, brown, or mottled. Adults are small, generally 1 2 mm in length. Bodies of adults are tubular with narrow, pointed, fringed wings. Two larval stages feed on plant parts above ground. Prepupal and pupal stages occur in soil. Mount adult species on microscope slide for identification. Potential Biological Control Keep soil on dry side. Entomopathogenic nematodes, including Steinernema feltiae and S. carpocapsae, control larval stages. Bacillus thuringiensis var. serotype H14 (Gnatrol) control larvae. Several IGRs control larvae, including Dimilin (Adept), Neem (Azatin, Neemazad) and S-kinoprene (Enstar II). Microscreening should exclude leafhoppers that migrate into greenhouse. Outdoors, control may not be necessary on most crops. Treat plants susceptible to viruses transmitted by leafhoppers with a systemic insecticide to kill the feeding insects. Microscreening over vents and greenhouse openings can exclude migrating adults. Predaceous mites, Amblyseius (=Neoseiulus) cucumeris and Iphiseius (=Amblyseius) degenerans, are used for first instar thrips larvae. Minute pirate bugs, Orius sp., feed on larvae and adults. Entomopathogenic fungus, Beauveria bassiana, infects thrips; direct fine mist spray onto pests. 23

33 Table 2.3 Monitoring For Pests In The Greenhouse (continued) Pest Twospotted spider mites (Tetranychus urticae) Whiteflies Bandedwinged whitefly (BWWF) (Trialeurodes abutilonea) Greenhouse whitefly (GHWF) (Trialeurodes vaporariorum) B strain and Q strain (Bemisia tabaci) Best Monitoring Method Pests tend to build up under hot conditions. Examine plants in warmest section of greenhouse for early infestations. Look for stippling of foliage. In heavy infestations, look for webbing on stems, flowers, and upper leaves. Use yellow sticky cards to monitor for adults. Place sticky cards near intake vents and doors to detect inwardmigrating adults. Plant inspection should detect immature stages on under-surface of foliage. Identification Features Larvae are very small and pale green with 6 legs. Protonymphs and deutonymphs are pale green to brown with 8 legs. Adults have 2 large black spots on each side and 8 legs. Adults are short in length (1 2 mm), white, and fly-like. Eggs are tiny, spindle-shaped, and laid on undersides of leaf surfaces. SLWF eggs start out white but turn amber-brown. GHWF eggs start white and turn to gray with time. Crawlers and other nymphal stages are oval, flattened, and translucent. Potential Biological Control The predaceous mite, Phytoseiulus persimilis, is an effective control. Amblyseius californicus is also used for control. Release Encarsia formosa early in crop cycle to suppress greenhouse whiteflies before population build-up. Suppress Bemesia tabaci whitefly by using Eretmocerus eremicus. An entomopathogenic fungus, Beauveria bassiana (Naturalis-O and BotaniGard), is effective against nymph stages of B. tabaci and GHWF. 24

34 Chapter 3 Screening Out Insect Pests David S. Ross, Extension Agricultural Engineer Introduction Screening, which is an IPM practice for blocking the movement of thrips, whiteflies, and aphids into greenhouses, can be very effective if you start with clean plants and keep doors closed. Place fine screening material over vents to block the entry of insects into the greenhouse. The screen will reduce crop damage caused by insects that normally migrate into the growing area. Be careful when you size the screening material because the screen s small openings can block airflow. The area of screening material has to be 2 to 5 times the area of the existing vents for air to have enough open space to pass through a screen s openings. Existing greenhouses require structural modifications to support the screening material. Management makes the difference when it comes to the effectiveness of the screening material. Do not leave doors open. Do not move contaminated plants into the greenhouse to populate it with the very insects the screening is meant to keep out. Maintain a clean house or the value of the screening material is lost. Greenhouse Static Pressure Considerations Fans have to overcome resistance as air moves around obstacles in the greenhouse and through the vents to pass through the greenhouse; this resistance is measured as a pressure loss. A static pressure loss of 0.03inch water gauge (w.g.) pressure is typical for fan ventilation systems. Evaporative cooling pads add resistance (Fig. 3.1). Fans are sized at a static pressure loss of or inch water gauge pressure. Because insect screening adds to the static pressure load, designers try to hold its pressure loss to 0.03-inch water gauge pressure. These design guidelines allow for some clogging before the fan static pressure sizing limit is reached. A manometer is a simple device that measures is the pressure drop in the house caused by the resistance to air flow (Fig. 3.2). One end of tube is inside and one end is outside. Liquid is pushed to lower pressure. Energy loss causes slight vacuum inside as air is pulled through it. Exhaust fan Plants Internal air movement X X X X X X Evaporative Cooling Pad = 0.07 inch w.g. Figure 3.1 Evaporative Cooling Pad Restrictions cause pressure losses as air moves through greenhouse. 25 Figure 3.2 Manometers A manometer meausures static pressure drop of airflow through greenhouse.

35 Approach Velocity Determines Area Some screening-material manufacturers have measured the static pressure loss of their material at different airflow rates or air velocities. The results show that as the air velocity (of the air moving through the screening material) increases the airflow resistance and static pressure increase. To avoid a reduction in the ventilation airflow, the velocity of air through the screening material must be limited to that velocity at which the static pressure is 0.03-inch w.g. This is called the approach velocity and is the maximum air velocity allowed (Fig. 3.3). Some manufacturers provide two or more screening materials. Hole sizes vary as do the applications Static pressure, inches water Air Velocity, fpm Figure 3.3 Resistance Curve Curve showing pressure loss for air movement at different velocities through screening material. for which they are suited. The anti-thrips material, which usually has openings that are smaller than the norm, generally is more restrictive to airflow; therefore its use requires more surface area. A variety of materials are available in various opening sizes and designs; for this reason the restriction on airflow varies considerably. You need data about the material you will be using in order to make an informed decision about required surface area (Fig. 3.4). Free open area Free open area Figure 3.4 Air Movement With Screening The free open area for air movement is reduced by the threads of the screening material. Sizing the Screening Some manufacturers provide the air velocity vs. static pressure information, which makes material selection easy. For example, a manufacturer states that a screening material reaches a static pressure drop of 0.03inch water gauge pressure at an approach velocity of 350 feet per minute (fpm). This represents the pressure drop or resistance to airflow through the material at the stated velocity. In other words we must spread the incoming air out over enough area to obtain the required ventilation rate, cubic feet per minute (cfm), without exceeding 350 fpm. Use the relationship of Airflow Rate equals Velocity times Area (Fig. 3.5). 26

36 Example: A greenhouse that requires 30,000 cfm ventilation rate. If the approach velocity is 350 fpm, the total screening area must be at least 30,000 divided by 350 or 85.7 square feet of screened area. The actual existing inlet louver area for CFM = fpm x ft 2 Figure 3.5 Ventilation Air Flow Ventiliation air flow (CFM) is air velocity (fpm), times open area of louver (ft 2 ) this house is likely less than half that area. The screening material cannot simply cover the inlet louvers. A box must be designed to provide a larger surface cover for air to enter before passing through the smaller inlet louver openings. For winter ventilation, the inlet design velocity is 700 fpm, which suggests that most greenhouses will need at least double the inlet area for the screening material used in this example. The design numbers will vary for each screen material. Retrofitting a Greenhouse with Screening The use of insect screening materials usually means retrofitting the greenhouse so the material can be properly installed. Since structures by different manufacturers vary somewhat, there is no one method for retrofitting. However, the addition of another hoop on the end of a Quonset house is one way of providing a surface to hold the screening material. Large gutter-connected houses use a second wall on one side to hold the screening material. The inside wall holds the inlet vents or vents plus pad cooling system for the house. Screening material can hang down from side vents to move with the vent as it opens and closes to protect the opening. Professional design assistance is recommended for major retrofitting. Roof Ventilation and Screening Although screening materials have been developed for roof vents, most materials do not provide much extra surface area for the necessary air movement. A pleated screening material is available that provides extra surface area when the vents are open. Naturally ventilated greenhouses are difficult to deal with because only temperature differences and wind usually at their lowest values during the worst summer heat cause the air to move. Adding the screening only further blocks the heat s escape. The relatively new open-roof greenhouse structure is the ultimate in natural or roof ventilation by being fully open during warm days. Insect screening would have to be installed similarly to a heat curtain in order to be effective in these houses. The screening would restrict airflow. An alternative is to use low-percentage shade fabric made with silver reflective material as a movable shade curtain to try to repel the inward migration of adult thrips, winged aphids, and whiteflies. This method has not been proved yet but is being tried as a low airflow restrictive method. Summary Insect screening can be effective in reducing insect entry into greenhouses. With fan systems, sufficient screening surface area is required to maintain an air velocity low enough to keep the static pressure to about 30 percent of the static pressure capability of the exhaust fans. Screening is not effective if doors are left open or contaminated plants are moved into the house. Naturally ventilated houses are difficult to operate using screening. Open-roof houses offer a new challenge to the grower for repelling insects. 27

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38 Chapter 4 Disinfecting a Greenhouse: Keeping Diseases and Insects in Check Stanton Gill, Extension Specialist Introduction A key element in developing an Integrated Pest Management (IPM) approach to disease and insect control in greenhouses is to regularly disinfect all working surfaces and equipment used in the greenhouse. The objective should be to reduce the movement of pathogens and pests on tools, mechanical equipment, flats, pots, and bench surfaces. It is a good idea to slow the development of resistance by rotating your use of disinfectants. Periodically, change from one disinfectant to another. The following disinfectants can be part of your rotation: Alcohol (70% isopropyl) Common isopropyl alcohol is an effective disinfectant that kills microbes on contact. The volatility of alcohol makes it best suited for dipping or swiping propagation equipment or shears. It is generally not practical as a soaking material. Chlorine Bleach (sodium hypochlorite) Sold under several brand names, chlorine bleach is the most widely used and least expensive disinfectant on the market. Once you mix chlorine bleach, it must be used within 2 hours or the chlorine will evaporate as chlorine gas. Chlorine solution exposed to sunlight or high levels of organic material will break down rapidly. Mix chlorine outside and avoid breathing the fumes from concentrated formulas. The Clorox brand of chlorine bleach is the only brand sold that has an Environmental Protection Agency registration number for use as a disinfectant. Most household bleach has a chlorine concentration of percent. A 0.6 percent final solution concentration will kill most microbes that infest surfaces. To obtain a 0.6 percent concentration, use one part household bleach with nine parts water. Sodium hypochlorite can accelerate corrosion of some metals and may damage some plastic surfaces. Hydrogen Dioxide Sold under the brand name ZeroTol, hydrogen dioxide can be used as a surface sanitizer for greenhouse structures, benches, pots, and tools. Use the ratio of one part hydrogen dioxide to 49 parts water. Quaternary Ammonium Chloride Salt Quaternary salts, which are sold under the brand names Geenshield, Physan 20, and Prevent, are much more stable than alcohol and chlorine bleach. Soak objects for at least 10 minutes for proper disinfecting. Quaternary salts are inactivated by organic material. Flats and pots should have all organic material removed before disinfecting with quaternary salts. 29

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40 Chapter 5 Pesticide Application Equipment: Selection and Calibration David S. Ross, Extension Agricultural Engineer Introduction Proper application of pesticides is essential for achieving the desired control. Applying pesticides is an unpopular and time-consuming task. You must use the correct application equipment. No one type of sprayer can do all tasks. Calibrate the equipment to ensure that the proper amount of chemical reaches the target. Reaching the target does not happen automatically; the operator influences the success or failure of the task. Actually, the operator must time the spraying and accurately proportion the chemical over the target area, being careful to direct the spray in a manner that achieves good coverage of all the plant parts, foliage and flowers. While spraying is a principal means of controlling insects and disease, growers must identify and eliminate the source of the insect or disease problem to reduce the frequency of sprayings. Weeds or grasses near the greenhouse may harbor the insects or disease carriers. A compost or discard pile of noncomposted plants located near the inlet vents can also be a source of insects or disease. Sites that might harbor pests that can move into the greenhouse must be kept clean. Insect screening, if properly used, can help to reduce the quantity of insects entering the greenhouse. Rotating the classes of chemicals you use will help delay resistance to chemical control from developing. Droplet Size Versus the Pest One of the primary differences among the several different types of sprayers available is the size of the droplet each produces. Your ultimate goal is to reach the target with pesticide. Reaching the smallest insects, mites, and disease organisms requires complete coverage with tiny droplets or wetting to the point of runoff. For good coverage a contact insecticide or fungicide must come in direct contact with the target; a systemic pesticide must be absorbed by the plant. Weeds are killed by herbicides that are absorbed by foliage; large droplets supply adequate coverage of the plant for absorption to take place and reduce the chances of the herbicide drifting onto the desired crop. There are optimum spray drop sizes for specific targets (Table 5.1). Note the small droplet sizes for small, flying insects and larger droplets for herbicides. The reason for these droplet sizes is illustrated by looking at the coverage of different size droplets on some surface areas. Droplet sizes are given in microns or onemillionth ( ) of a meter. For reference, 1 micron is inch, and a human hair is about 100 microns ( inch) in diameter. Table 5.1 Optimum Spray Drop Sizes For Various Targets Source: Adapted from Matthews 1979 Target (in microns) Flying insects 10 to 50 Insects on foliage 30 to 50 Diseases on foliage 40 to 100 Growing medium and weeds 250 to 500 (avoids spray drift) 31

41 There is a relationship between droplet size and the number of droplets per unit area (Table 5.2). A great number of small droplets give better coverage than a few large droplets. To reach a small target (insect or mite), therefore, use small droplets; the more droplets that fill a given area, the more likely the target is to make contact with a droplet. Note that 1 square inch equals 6.45 square centimeters; 19,099 drops per square centimeter equals 123,189 drops per square inch. The mathematical relationship between diameter of a droplet and its volume is a cubic one. A 100-micron droplet reduced to a 50-micron size results in eight 50-micron droplets. In other words, the volume of one 100-micron droplet equals the volume of eight 50-micron droplets. A 100-micron droplet reduced to 10-micron droplets results in 1, micron-size droplets. Although a small insect or mite may walk around a 100-micron droplet on a leaf, 1, micron droplets will cover the leaf, which makes the insect unable to avoid them. The increased coverage makes it hard to avoid the chemical. Table 5.2 Theoretical Spray Coverage Applying one liter per hectare with various spray drop sizes. Drop Diameter (microns) Number of Drops Per Square Centimeter 10 19, , , Types of Sprayers The three primary types of sprayers used in greenhouses are 1) Hydraulic or high-volume hydraulic, 2) Targeted low volume, and 3) Fog or ultralow volume. Each sprayer has a purpose; a greenhouse operation will require two or more types of sprayers for various tasks. Primary differences among sprayers are the quantity of water used, the operating pressure, and the size of droplets produced. Hydraulic A hydraulic or high-volume sprayer uses a high flow rate of water to wet the foliage to the point of runoff. This sprayer uses standard rates of chemicals and large volumes of water. The droplets coming from the sprayer are generally more than 100 microns in size. The sprayer applies herbicides in large droplets of 200 to 400 microns at a low pressure of 15 to 60 pounds per square inch (psi) to avoid drift. Insecticides and fungicides are applied at higher pressures more than 60 psi to achieve droplets of 100 microns or less in diameter. The lower-volume greenhouse sprayers use 500 psi and 2 to 4 gallons per minute (gpm) flows to wet to runoff. The quantity of water to use depends on the specific sprayer and nozzle, the spraying technique of the operator, and the size of the crop. Calibrating the sprayer according to the operator and the crop is essential for mixing the correct amount of spray mix. Ten thousand square feet of crop early in its growth may require 15 to 20 gallons of water. As the crop reaches maturity and has more foliage, achieving good coverage may require 30 to 50 gallons of water. The hydraulic sprayer can do a good job of covering foliage. The operator can see the spray on the foliage and know whether or not the target has been hit. The larger flow of water provides force to move foliage aside in order to penetrate the canopy and stir the leaves. By using a low application rate the operator can hold the spray nozzle onto a target long enough to achieve penetration without excessive wetting. 32

42 Low Volume The targeted low-volume sprayer may be hydraulic, air assisted, electrostatic air assisted, or rotary. The object of using this type of sprayer is to use small droplets and a low quantity of water to carry the chemical to the crop. The low-volume hydraulic sprayer utilizes high pressures between 1,000 and 3,000 psi to break the droplets into roughly 50-micron size or smaller; however, these sprayers use less water and produce a mist that is too fine to show a wetting pattern. There is no wet-to-runoff pattern to observe. The operator aims the sprayer at the target and sprays until the air volume under the foliage is filled with spray. The operator is responsible for obtaining full coverage. A concentrated chemical mix (chemical plus water) can be used because less water will be applied. The calibration process is more difficult for low-volume sprayers because the spray does not wet the foliage as visibly as the high-volume hydraulic sprayer does. Special water-sensitive paper that indicates coverage is available (from some sprayer or chemical suppliers). The paper changes color when droplets of water land on it. Attach pieces of this paper to plants in various places before spraying and examine the paper afterward to observe how well the spray droplets were distributed during calibration or normal spraying. The calibration process also helps to determine the amount of water needed to cover a given area. Calibration is still very important for spray mix preparation to avoid costly waste. Calibration information may also be useful in determining legal amounts of chemical to use with a measured amount of water for covering a given area. It may be necessary to consult the chemical producer for the allowable mixing ratios. Air-assisted low-volume sprayers use air as the primary carrier of the chemical. High-speed air strikes the stream of liquid chemical or chemical and water being injected into the sprayer and breaks the stream into small droplets. The air then carries the liquid to the plants. The speed at which the sprayer moves past the foliage determines the penetration of air into the foliage to deliver the chemical. Slow movement may be necessary to allow the air mass created by the sprayer to penetrate into thick foliage, pushing the air in the foliage out the other side. The sprayer air volume must displace the air volume under the foliage. Electrostatic sprayers produce fine droplets that 30- to 60-micron in size, which are electrically charged and then air-blasted into the crop foliage. The negatively charged particles are attracted to any surface and can provide coverage that is as good as the coverage from a high-volume sprayer. A sprayer with a spinning or rotary disk is used to impact and break a stream of water into droplets that are 60 to 80 microns in diameter. A variety of sizes are available for greenhouse use. Fog or Ultra-Low Volume The fogger uses little water (2 liters per 10,000 square feet) and produces fine droplets less than 25 microns in diameter. When you distribute pesticides in very small droplets as a fog your rate of application is reduced. Some chemicals are not labeled for reduced rates and some formulations are not intended to be used in ultralow-volume sprayers. Clogging will occur with some chemicals; special carriers are needed with some pesticides. Mechanical cold foggers operate between 1,000 and 3,000 psi to force the mixture of chemical and a small amount of water through the nozzle. Thirty-micron droplets drop out of the air fairly quickly, but 5micron droplets float in air currents for hours. These sprayers use no chemical additives. Thermal foggers use a pulsing jet engine to produce a highly visible fog that can stay suspended in the air for up to 6 hours. Inside the thermal fogger, a gasoline and air mixture explodes in an enclosed resonator. The explosion rushes out as a jet stream. A chemical solution is injected into the jet stream and is blown apart into very small 0.5- to 30-micron particles. A carrier solution added to the mix causes a visible fog, eliminates the evaporation of droplets, and ensures uniform particle sizes. 33

43 An aerosol micro-particle generator sprayer is available. It uses an oilless air compressor to produce highpressure air. The air flows through a special nozzle to produce superfine fog particles of 0.5 to 10 microns in diameter. These particles can stay suspended for up to 6 hours. No special carrier solution is required. One commercial company packages a pure technical active ingredient in a container that emits the material as a fog. You open an aerosol can or cans and set them down in the greenhouse, starting at the point farthest from the exit and walking toward the exit. The company claims 40 percent of the material reaches the undersides of foliage. Some sprayers have a fan to move the air around the greenhouse; if not, use the HAF (horizontal airflow fans) to distribute the fog throughout the building. Calibration Proper sprayer use involves following a procedure that measures the amount of water or spray used to cover a given area or volume at a known rate of operator travel speed. Calibration, which tells you the amount of liquid that was applied to a known unit area, enables you to prepare chemical spray mixes properly. For a hydraulic sprayer fill the sprayer with water, spray a known area of the greenhouse crop, and then record the time required for spraying. The goal is to spray the water to achieve uniform coverage. Next, measure the water required to refill your sprayer. Calculate the spray rate by dividing the gallons used by the area covered. Adjust the rate by adjusting the nozzle or your walking rate. If a nozzle wears out or an operator rushes and does a poor job of coverage, the amount of spray used should alert the owner or operator to a problem. The operator s movement is critical to applying the correct amount of spray. Measuring the output of a nozzle will verify its rate of flow. The manufacturer can provide information about the discharge rate (gallons per minute) of each nozzle at several pressures. A good quality sprayer should have a pressure gauge to tell if the sprayer is operating properly (on all sprayers moving liquid at pressure). Set and/or record the pressure of liquid going to the nozzle. Catch the discharge of the nozzle in a container for a measured period of time. Measure the amount of liquid collected. Calculate the flow through the nozzle in gallons per minute using the measured volume and time. Compare this value to the manufacturer s discharge rate for the pressure observed. If you follow the procedure fairly accurately, the measured discharge rate should approximate the rate presented in the manufacturer s data. Small differences may be caused by wear. You can calibrate a low-volume sprayer in a similar manner. Carefully direct the low-volume sprayer into the foliage to exchange the air under the foliage with the air containing the pesticide. Practice and calibration help the operator to establish the amount of water and chemical to use for large jobs. Wear chemical-resistant personal protective equipment (PPE) during the calibration and during the spraying the operator needs to experience the same environment during calibration as during actual spray application. Protective equipment is a must during pesticide application. 34

44 Part 2 Insect and Mite Management Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Insecticide and Miticide Classes Biological Control of Greenhouse Pests Biopesticides and Reduced-risk Pesticides Understanding Insect Growth Regulators Impact of Selected Pesticides on Bees Insecticides Registered for Greenhouse Ornamentals Insecticides Registered for Vegetable Transplants

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46 Chapter 6 Insecticide and Miticide Classes Stanton A. Gill, Extension Specialist Introduction Insecticides and miticides are tools used by growers to manage insects and mites. Generally these products do not eliminate the problems, but they maintain mite and insect populations at acceptable levels. The biological world is designed to modify and adapt to overcome any challenge to its survival. With this information in mind, use insecticides and miticides correctly to manage pest problems and to delay the development of resistance to chemicals. IRAC The Insecticide Resistance Action Committee (IRAC) is an organization dedicated to slowing the development of pest resistance. It was founded in 1984 as a specialized technical group to help prevent or delay the development of resistance in insect and mite pests. Resistance Defined Resistance to insecticides, miticides and fungicides is defined by IRAC as a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendations for that pest species. Rotation Ways to Delay Resistance Development The assumption is that rotations of compounds from different mode of action (MoA) classes remain the most viable resistance management technique. Most insecticides and miticides affect insects and mites in specific ways. IRAC currently classifies insecticides and miticides into 28 different modes of action. This publication identifies only those insecticides and miticides used in greenhouses by their modes of action Table 6.1). Timing for chemical class rotation is slightly different for insects and mites compared to disease control. To delay the onset of resistance to pesticides, it is usually recommended to rotate from one pesticide to another one that has a different mode of action after 1 to 2 insect or mite generations. This chart may be used to identify the mode of action of a pesticide and to determine other pesticides with different modes of action that may be used in a pesticide rotation plan. 37

47 Table 6.1 Mode of Action (MoA) Classification of Insecticides and Miticides Used in Maryland Greenhouse Operations Please Note: IRAC created 28 groups. We have not included groups that do not have any chemicals registered for use in greenhouses and nurseries. Group Main Group and Primary Chemical Class Trade Name (Active Ingredient) Site of Action 1A Acetylcholine - nerve action Carbamates Mesurol 75-W (methiocarb) Carbaryl 4L, Sevin (carbaryl) 1B Esterase inhibitors nerve action Organophosphates Acephate 97 UP; Orthene TT&O 97; 1300 Orthene TR (acephate) DuraGuard ME; Dursban 50 W (chlorpyrifos) *Duraplex TR (chlorpyrifos + cyfluthrin) 3/3A Sodium channel modulator Pyrethroids Attain TR, Decathlon 20 WP; Menace GC, Onyx Pro, Talstar Select, Up-Star, Widsom (bifenthrin) Decathlon 20 WP (cyfluthrin) *Discus (cyfluthrin+imidacloprid) Pyreth-It, Pyronyl, Scimitar (lamda-cyhalothrin) Astro, Ambush 25W, *Perm- Up 3.2 EC, *Pounce 25 WP (permethrin) Pyganic (pyrethrins) Safer End All TM Insecticidal Soap with Pyrethrin Insecticide Pyrethrum TR, Pyrenone Crop Spray, Prentox Pyronyl Crop Spray, Pyreth-It Formula 2, Pyreth-It (pyrethrin + piperonyl butoxide/pbo) Mavrik Aquaflow (tau-fluvalinate) 4A Nicotine acetylcholine receptor disruptors- nerve action Neonicotinoids TriStar (acetamiprid) *Discus (cyfluthrin+ imidacloprid) Lada, Bounty, Mallet, mantra, marathon (imidacloprid) Safari (dinotefuran) Flagship (thiamethoxam) 4B Nicotine Fulex Nicotine Fumigator 4C Sulfoximine Sulfoxaflor XXPire (Sulfoxaflor) 5 Nicotine acetylcholine Spinosyns Conserve SC (spinosad) receptor agonist (nerve action) Spinetorum XXPire WG 38

48 Table 6.1 Mode of Action (MoA) Classification of Insecticides and Miticides Used in Maryland Greenhouse Operations (continued) Group Main Group and Primary Chemical Class Trade Name (Active Ingredient) Site of Action 6 Chloride channel activator Avermectins Ardent, Avid 0.15EC, Minx, Merlin (abamectin) Sirocco (bifenazate + abamectin) 7A Juvenile hormone mimic Juvenile hormone Enstar AQ (kinoprene) analogues 7B Fenoxycarb Preclude TR, (fenoxycarb) 7C Pyriproxyfen Distance, Fulcrum (pyriproxyfen) 9B Selective feeding blocker Pymetrozine Endeavor (pymetrozine) 9C Flonicamid Aria (flonicamid) 10A Mite growth and embryogenesis inhibitor Clofentezine Hexythiazox Ovation SC (clofentezine) Hexygon DF (hexythiazox) 10B Etoxazole TetraSan (etoxazole) Beethoven TR 11A1 Microbial disruptors of insect Bacillus thuringiensis Gnatrol WDG midgut membrane var israelensis 11B2 B.t. var kurstaki Dipel Pro, Biobit HP, Deliver, Javelin WG, Thuricide 12B Inhibitors of oxidative Organotin miticides ProMite (fenbutatin oxide) phosphorylation, disruptor of ATP formation 13 Uncoupler of oxidative Chlorfenapyr Pylon, Pylon TR (chlorfenapyr) phosphorylation via disruption of H proton gradient 15 Inhibitors of chitin biosynthesis, type 0, Lepidopteran Benzoylureas Adept, Dimilin SC (diflubenzuron) Pedestal (novaluron) 16 Chitin synthesis inhibitor Buprofezin Talus (buprofezin) 17 Molting disruptor Cyromazine Citation (cyromazine) 18 Ecdysone receptor agonists Meth-oxyfenozide Intrepid 20B Mitochondial electron transport inhibitor Acequinocyl Shuttle O (acequinocyl) 21A Site 1 Mitochondrial electron transport inhibitor METI acaricides 21 B Tolfenpyrad Hachi-Hachi 22 Voltage-dependent sodium Indoxacarb Provaunt channel blocker Akari 5 SC(fenpyroximate) Magus (fenazaquin) Sanmite (pyridaben) 39

49 Table 6.1 Mode of Action (MoA) Classification of Insecticides and Miticides Used in Maryland Greenhouse Operations (continued) Group Main Group and Primary Site of Action Chemical Class 23 Inhibitors of lipid biosynthesis Tetronic and tetramic acid derivatives 25 Neuroactive (unknown mode of action) Cyflumetofen 28 Ryanodine receptor modulator Cyantraniliprole Mainspring Unclassified: Compounds of unknown mode Azadirachtin listed but not of action classified by the IRAC Beauveria bassiana fungus Bifenazate Burkholderia strain A396 Chromobacterium subtsugae strain PRAA4-1 Trade Name (Active Ingredient) Entrust, Judo (spiromesifen) Kontos (spirotetramat) Triact (clarified hydrophobic extract of neem oil); Golden Pest Spray oil (Soybean oil); UltraPure oil/suffoil-x, TriTek (mineral oil) M-Pede (potassium salts of fatty acids) Sultan Azatin ), Azatin XL, Aza-Direct, AzaGuard, AzaSol, Molt-X, Ornazin 3% EC BotaniGard, Mycotrol O Floramite (bifenazate) Venerate [D7] Grandevo PTO Isaria fumosoroseus NoFly, Preferal (formerly Paecilomyces) Metarhizium anisopliae Met 52 Strain F52 Metaldehyde Deadline Nematodes Millenium (Steinernema (beneficial/entomopathogenic) carpocapsae) Entonem, Nemasys, NemaShields, ScanMask (Steinernema feltiae) Pyridalyl Overture (pyridalyl) Pyrifluquinazon Rycar Sulfoxaflor + Spinetorum XXpire WG Insecticides Desiccation of membrane Oil Ecotect [D11] (Rosemary oil + used in disruptor Peppermint oil) greenhouse Iron Phosphate + Bug-N-Sluggo not classified Spinosad by IRAC ** Modes of action (MoA) see IRAC Web site for additional information: * Mixed IRAC groups 40

50 Chapter 7 Biological Control of Greenhouse Pests Stanton A. Gill, Extension Specialist Introduction When using biological control organisms to control plant pests, it is necessary to release the beneficial insects or apply entomopathogenic fungi or nematodes early in the crop cycle before plant pests are present or established in high numbers. The turnover time for bedding plant crops is short so there is a limited time for predators or parasitoids to reproduce. Regular monitoring is important when using beneficial organisms. Inspect plug shipments closely to avoid bringing pests into the greenhouse. The egg or sessile stages of insects are especially difficult to detect so when plants reach the production area, pest populations may explode. Long-term and high value greenhouse grown crops such as hanging baskets, poinsettias, pansies, and chrysanthemums are good choices for biological control programs. The diversity of crops in any one greenhouse can make biological control use a challenge. Be sure to know the crops and plant pests that typically infest them and plan a biological control program accordingly. Certain pesticides are compatible with biological control organisms (Table 7.1). Several widely available arthropod pathogens are discussed below. Insect pathogens are more cost-effective compared to releasing predators and parasitoids. Bacillus thuringiensis (Bt) Bacillus thuringiensis is a widely-used pathogen for controlling early instars of caterpillars. Under cool, dry conditions, Bt can be stored for up to 2 years. Insects must feed on the bacterium so when applying Bt thorough coverage of the plant is important. Bacillus thuringiensis var kurstaki and B. thuringiensis var aizawai control caterpillar pest species that include cabbage looper, corn earworm, European corn borer, Florida fern caterpillar, saltmarsh caterpillar, and the variegated fritillary caterpillar. B. thuringiensis var kurstaki can be used to control most caterpillars. It works best when it is applied while early instar larvae are actively feeding. Some strains of B. thuringiensis are more effective against select species than other strains of the pathogen. Bacillus thuringiensis israelensis (serotype H14) applied to the soil can kill fungus gnat larvae occurring in moist soil. To control fungus gnats, repeat applications are often necessary because fungus gnats often have overlapping generations and the bacteria is only effective against early instar larvae. Propagation areas kept under mist maintain soil conditions best suited to using B. thuringiensis (serotype H14). Entomopathogenic Nematodes Entomopathogenic nematodes thrive in moist conditions and can be lethal to insects such as fungus gnats, pupating thrips, and black vine weevil larvae. Commercial producers use two different methods for rearing entomopathogenic nematodes. Nematodes may be produced in vitro on an artificial diet or they may be reared in vivo in living hosts. Nematodes such as Steinernema carpocapsae and S. feltiae produced in vitro are usually formulated in a manner enabling them to be stored for up to 6 months. Nematodes such as Heterorhabditis bacteriophora that are produced in vivo may be stored for up to 3 months. To maintain the nematodes effectiveness it is important to ask the supplier about the method of production and recommendations for storage. 41

51 Nematode formulations include slurries, granules within inert clay carriers, gels, and sponges. Water must be added to all formulations in order to rehydrate the nematodes. Apply nematodes as a soil drench for even distribution throughout the substrate and to maximize their contact with soil-dwelling insects. Keep soils moist and soil temperatures above 16 C (60 F) and below 32 C (90 F). The infective nematode finds a susceptible host and enters the insect s body through natural openings such as the mouth, spiracles, or anus. The nematodes feed and release bacteria which live symbiotically in the insect s gut. The bacteria rapidly multiply, killing the insect. The nematodes mature and reproduce in the colonized insect cadaver. These infective stages leave the insect s body and return to the soil or substrate to search for other hosts when no more food is available. Entomopathogenic Fungi Entomopathogenic fungi are pathogens that infect and kill insects. Insects are killed when they come into contact with these fungi. Beauveria bassiana (Balsamo) Vuillemin is an entomopathogenic fungus that may control infestations of whiteflies, some thrips, and certain aphid species. Available as suspensions and wettable powders, the active ingredients are conidia (spores) which are sprayed directly onto the pests. The spores must contact the host directly to be effective so good spray coverage is critical. Hyphae, small tubes that grow from the conidia, use a combination of mechanical pressure and enzymes to break through the exoskeleton of the pests to enter the body cavity and attack the internal organs. The infected insect stops feeding and dies within a few days. 42

52 Table 7.1 Compatiblity of Pesticides and Biological Control Chemical Trade Name Effects on Beneficials Abamectin Abamectin SPC, Avid, Lucid, Minx Immediate contact kills mites. Less harmful to insects. Relatively long residual toxicity. Toxic to many beneficial insects, safe with beneficial nematodes and fungi. Toxic to honey bees. Acephate Acephate 97 UP, Orthene TTO, 1300 Orthene TR Toxic.Immediate contact kills beneficial organisms. Some residual toxicity. Toxic to honey bees. Acequinocyl Shuttle Considered safe/non-toxic. Azadirachtin AZA-Direct, AzaGuard, Aza- Sol, Azera, Azatin, Molt-X, Ornazin, Immediate contact is somewhat harmful/moderately to toxic. No long residual toxicity. Applying via irrigation is less toxic to beneficials. Acetamiprid TriStar Moderately toxic to beneficials. Bacillus thuringiensis Serotype 14 (+Bti) Gnatrol WDG 43 No impact on beneficial organisms. Needs 3 applications at 7-day intervals for best efficacy. No impact on beneficial organisms. Bacillus thuringiensis (Kurstaki strain) Dipel Pro, Biobit HP, Deliver, Javelin WG, Thuricide Beauveria bassiana BotaniGard, Mycotrol Should not impact mobile predators, but parasites such as Encarsia formosa and other parasitic wasps may be killed when the internal parasite is infecting the target pest. Bifenazate Floramite Non-toxic to most beneficials. However, toxic to predatory gall midge, Feltiella acarisuga, and aphid midge, Aphidoletes aphidimyza, larvae. Moderately toxic to predaceous mite larvae of Amblyseius swirskii and Aphidius. Bifenazate + Abamectin Sirroco Toxic to many beneficial insects; safe with beneficial nematodes and fungi. Toxic to honey bees. Bifenthrin Attain, Menace, Onyx Pro, Talstar Select, Upstar, Wisdom Safe for beneficial nematodes. Toxic to most beneficials. Toxic to honey bees. Low toxicity to Aphidius spp. Buprofezin Talstar, Talus Insect growth regulator. Low toxicity to most beneficials except beetles.

53 Table 7.1 Compatiblity of Pesticides and Biological Control (continued) Chemical Trade Name Effects on Beneficials Chlorfenapyr Pylon Toxic to many beneficials except Orius spp. Chlorpyrifos DuraGuard Toxic to most beneficials. Toxic to honey bees. Chlorpyrifos + Cyfluthrin DuraPlex Toxic to most beneficials. Clofentezine Ovation Non-toxic to most beneficials. Chromobacterium subtsugae strain PRAA4-1 Grandevo PTO Toxic to bees exposed to direct treatment and to aquatic invertebrates. Toxic to certain nontarget terrestrial arthropods. Cyflumetofen Sultan Compatible with most biological control organisms used for mite control. Cyfluthrin Decathlon Toxic to most beneficials. Moderately toxic to beneficial nematodes. Cyromazine Citation Non-toxic to most beneficials -except toxic to aphid midge, Aphidoletes aphidimyza, green lacewing, Chrysopa carnea, and predatory gall midge, Feltiella acarisuga. Diflubenzuron Adept Non-toxic or low toxicity to most beneficials. Toxic to green lacewing Chrysopa carnea, and to nymph of predatory bug, Macrolophus caliginosus (= M. pygmaeus). Dinotefuran Safari Toxic to honey bees. Etoxazole Beethove TR, TetraSan Toxic to predatory mites. Fenazaquin Magus Toxic to predatory mites, predaceous gall midges. Non-toxic to green lacewings and parasitic wasps. Moderate to low toxicity to predaceous bugs. Fenbutatin-oxide ProMITE Low toxicity to most beneficials; moderately toxic to larval Anthocoris nemoralis, Aphidoletes aphidimyza, and Anthocoris nemoralis. Fenpropathrin + Acephate Tame/Orthene TR Toxic to honey bees. Fenpyoximate Akari Toxic to predaceous mites. Moderately toxic to predaceous wasps, Aphidius spp. Hexythiazox Hexygon Non-toxic to most beneficials. 44

54 Table 7.1 Compatiblity of Pesticides and Biological Control (continued) Chemical Trade Name Effects on Beneficials Imidacloprid AmTide, Marathon, Benefit 60 WP, Bounty, Mallet, Mantra, Quali-Pro Imidacloprid Toxic to most beneficials as a foliar spray. Toxic to honey bees. Drench application has low to moderate toxicity except toxic to Euseius gallicus, Stratolaelaps scimitus, and Macrolophus pygmaeus. Drench is moderately toxic to beetle larvae, Dacnusa sibirica, and Diglyphus isaea. Imidacloprid + Cyfluthrin Discus Toxic to most beneficials. Toxic to honey bees. Insecticidal soap DES-X, M-Pede (Bayer, Bonide, natural Guard, Safer) Immediate contact is somewhat harmful. Little or no residual toxicity. Meth-oxyfenozide Intrepid Toxic to Macrolophus pygmaeus and Orius spp. Nematodes, beneficial (Entomopathogenic): Steinernema feltiae, Steinernema carpocapsae, and Heterorhabditis bacteriophora Oils Nemasys, Entonem, Millenium, NemaShield, ScanMask FERTI-LOME Horticultural Oil Spray; Golden Pest Spray Oil, JMS Stylet oil, Lesco Horticultural Oil #019492; MONTEREY Horticultural Oil; PureSpray Green; RTSA Horticultural oil; Saf-T-Side oil; SuffOil-X; TriTek; Ultra- Pure Oil 45 No known impact on parasites or predators. Entomopathogenic nematodes are usually applied as a soil drench for fungus gnat larvae control. Immediate contact is somewhat harmful. Little or no residual toxicity. Not compatible with some beneficials. Product has no residual effect. Mineral oil is toxic to Macrolophus pygmaeus and moderately toxic to Orius spp., Amblyseius spp. and Anthocoris nemoralis. Novaluron Pedestal Moderately toxic to beetle larvae, Macrolophus pygmaeus and Orius spp. nymphs. Permethrin Astro Highly toxic to most beneficials. Toxic to honey bees. Low toxicity to beneficial nematodes (as a foliar application) and the entomopathogenic fungus, Paecilomyces fumosoroseus. Pymetrozine Endeavor Non-toxic to most beneficials except moderately toxic to Aphidoletes aphidimyza, Macrolophus pygmaeus, and Feltiella acarisuga. Pyrethrins Pyganic Highly toxic to most beneficials.

55 Table 7.1 Compatiblity of Pesticides and Biological Control (continued) Chemical Trade Name Effects on Beneficials Pyrethrins + PBO Pyrenone, Pyrethrum TR Immediate contact kills beneficials. Has relatively short residual toxicity. Pyrethroid (lamda-cyhalothrin) Pyreth-It, Pyronyl, Scimitar Highly toxic to most beneficials. Toxic to honey bees. Pyridaben Overture 35 WP Non-toxic to green lacewings and Paecilomyces fumosoroseus. Moderately to highly toxic to most other beneficials. Pyriproxyfen Distance Non-toxic to most beneficials, however highly toxic to Phytoseiulus persimilis and Encarsia formosa larvae. Sulfoxaflor (Isoclast R ) + Spinetorum Spinosad (Saccharopolyspora spinosa) XXPire WG Conserve Entrust Judo No significant impact upon predators or parasitoids. After three hours of drying time, risk to pollinators is greatly reduced. Non-toxic to Aphidoletes aphidimyza, green lacewing, coleoptera, Feltiella acarisuga, Stratolaelaps scimitus. Moderately to highly toxic to other beneficials. Toxic to honey bees. Toxic to bees for 3 hours following treatment. Toxic to fish and aquatic invertebrates. Thiamethoxam Flagship 25 WG Flagship 0.22 G Toxic to wildlife and highly toxic to aquatic invertebrates. Toxic to bees exposed to direct treatment on blooming crops. Tau-fluvalinate Mavrik Aquaflow Highly toxic to most beneficials and predaceous mites. Lower toxicity to green lacewing. Low toxicity to bees. Foliar spray is non-toxic to beneficial nematodes. Tolfenpyrad Hachi-Hachi Has shown ovicidal activity, suppression of ovipositioning and anti-feeding activity on targeted insect pests. Check label for phytotoxicity information. 46

56 Aphids Introduction Various species of aphids are a problem in greenhouses on both vegetable and ornamental crops, particularly on young plants, between late fall and early spring. Aphids are one of the most difficult insects to control with sprays because of their remarkable reproductive ability. Females, which do not mate or lay eggs during the summer, are parthenogenic (do not need a male to reproduce) and give birth to as many as 5 live young per day. If even one aphid survives a pesticide application (some always do), she can generate a new colony and reinfest the crop. Aphids feed on plant sap, secrete honeydew onto the plant, and inject toxic substances into it. Plant damage can be seen as curled leaves, honeydew growing on fungus, and virus symptoms. Biological Control For Aphids Before attempting to use biological control for aphids in a greenhouse, investigate the economics, shipping routes, availability, suitable species, release rates, and timing. It also helps to know which species of aphid you are trying to control because some predators and parasites are effective only on certain aphid species (Table 7.2). The predatory aphid midge, Aphidoletes aphidimyza, is excellent for controlling more than 60 aphid species, especially green peach aphid. Midges are shipped as pupae. Place one to two pupae on each potted plant; for bedding plants place 3 to 5 larvae per square yard of bench area. Continue biweekly releases until the aphids are controlled. This predator thrives under humid conditions. For controlling melon aphids, the parasitic wasp, Aphidius colemani, is the preferred beneficial species to use. Try one to three aphid midge cocoons per square foot of growing area. In northern greenhouses during the short days of fall and winter, this predator requires supplemental lighting to stay active. Aphidius matricariae is a parasitic wasp used for controlling potato aphid and green peach aphid. These parasitic wasps reproduce by laying eggs in aphids and typically produce tan or gold aphid mummies. There will be a round hole where the adult parasite has chewed its way out of the aphid mummy. Aphidius ervi is a parasitic wasp used for controlling potato aphid and foxglove aphid. These parasitic wasps produce gray to brown aphid mummies. Another method of control is using pathogens that infect aphids. Beauveria bassiana is one of the most effective entomopathogenic fungi for aphid control. This insect is sold under two brand names, BotaniGard and Naturalis T&O. Conidia of the fungus are mixed with water and applied as a fine spray. Making direct contact with the aphids is important. Use a fine mist sprayer with droplet sizes of 100 microns or less to ensure the best contact. The conidia that make contact with the aphid germinate, penetrate the body of the aphid, and kill the pest. In the spring and summer, aphids shed their skins every 3 to 4 days which may reduce the efficacy of the fungus. Repeated applications at 3- to 5-day intervals usually ensures that conidia are present on the skin long enough to cause infection. Some growers use Beauveria bassiana applications in combination with one or more chemical controls. Using Banker Plants for Biological Control of Aphids Aphids are a key pest on bedding plants, herbs, and vegetable transplants such as salvia, zinnia, snapdragon, basil, cucumber, melon, celery, tomato and eggplant. Melon aphid, Aphis gossypii, green peach aphid, Myzus persicae, foxglove aphid, Aulacorthum solani, and potato aphid, Macrosiphum euphoribiae, are often found on greenhouse crops. Consider using banker plants as a way to maintain parasitoid populations when releasing them in greenhouses. 47

57 Barley banker plants can be used with bird cherry oat aphid, Rhopalosiphum padi, for biological control of aphids in greenhouses. The idea is to establish a population of bird cherry oat aphids on the barley plants first, and then take the potted barley plants out of a screened area and introduce the parasitoids. The barley plants are grown in a screened chamber so parasites are not able to infest the aphids being introduced to the plants and crash the population. It is important to keep a steady supply of bird cherry oat aphids reproducing on the barley plants. In Maryland, start barley plants in February or March. It is important to get the parasitic wasps established early in the season. The bird cherry oat aphids are shipped on barley plant plugs. Put these plugs among the caged barley plants. It takes about three weeks for bird cherry oat aphids to build up on the barley plants before setting some of them out in the greenhouse as needed. Bird cherry oat aphids feed only on monocots so use only with broadleaf bedding plants, herbs and vegetables. Order the parasitoids for delivery to coincide with setting out aphid infested barley banker plants among the greenhouse crop. A combination of A. colemani and A. ervi is a good choice if you are unsure of the aphid species present. The bird cherry oat aphids are maintained as a steady food source for the parasitoids which are also feeding on the other aphid species present on the greenhouse crops. Monitor the crop for parasitized aphid mummies. 48

58 Table 7.2 Biological Control of Aphids Beneficial Target Pest Favorable Environment Aphidius colemani Green peach aphids, F; (parasitic wasp) melon aphids tolerates cool temperatures, low light Aphidius ervi (parasitic wasp) Aphidius matricariae (parasitic wasp) Aphidoletes aphidimyza (gallmidge) Chrysoperla carnea (lacewings) Hippodamia convergens (lady beetle) Good for controlling potato aphids; also controls foxglove aphids Green peach aphids, potato aphids Aphids, including green peach aphids, cotton aphids Aphids (also feed on mealybugs, scales, spider mites, thrips, small caterpillars) Aphids (also feed on scales, thrips, small caterpillars) F; 50 75% relative humidity F; 60-80% relative humidity F; 50 75% relative humidity Characteristics Adults: tiny wasp lays eggs in aphids (for green peach aphids). Adults: tiny wasp lays eggs in aphids (for potato aphids). Adults: tiny wasp lays eggs in aphids (for green peach and potato aphids) Adults: lay eggs close to aphid colonies, are active at night, attracted to aphid colonies by smell of honeydew. Larvae: are orange, develop in aphid, bite aphid knee joints, inject a paralyzing toxin and suck out body contents F Adults: pale green, evening fliers. Larvae: aphid lions (alligator-like) can eat 60 aphids per hour; will cannibalize each other. Eggs: laid on the end of a long silk stalk on leaves near aphids. At least 68 F Adults and larvae are predaceous. Larvae: alligatorlike. Eggs: orange, bullet-shaped. Comments Granular carrier: aphid mummies and adults. Release 2 8 per yd 2 of growing area. Shipped in carrier as adults. Release 1 3 per yd 2 of growing area. Shipped in carrier as mummies. Release per yd 2 of growing area Need soil or gravel floor for larvae to pupate. Release 2 9 per yd 2 ; 2 3 releases one week apart. Aphid midge cocoons packed in moist vermiculite. Mature larvae drop to ground and burrow into soil to pupate. Go dormant under short-day conditions. Shipped in bran as eggs, young larvae, or adults; shipped as eggs on cards or in corrugated cardboard wafers. Adults tend to fly away and do not stay to lay eggs. Noticeable control in 2 weeks. Release 2 12 per yd 2 ; repeat every 2 weeks. Avoid residual chemical applications. Oil or soap can be applied before a release. 49

59 Caterpillars Biological Control For Caterpillars The larvae of various species of moths and butterflies that feed on plants in greenhouse production areas can be controlled with biologicals (Table 7.3). It is common to see the variegated fritillary feeding on pansies in the fall as well as imported cabbageworm, cabbage looper and the cross-striped caterpillar on cabbage and kale. Bacillus thuringiensis var kurstaki is a bacterium that offers good control of the early instar stages of caterpillars. The larvae ingest the bacterium. There are several species of Trichogramma (parasitic wasp) that feed on caterpillar eggs. The female oviposits into the caterpillar egg and the parasite kills the egg as it feeds. A parasitized egg usually turns black. Cotesia glomerata was introduced to North America in It is a small braconid wasp that parasitizes early instar larvae of imported cabbageworm caterpillars. It is currently not commercially available, but is often found parasitizing the cabbageworm larvae. Table 7.3 Biological Control of Caterpillars Beneficial Target Pest Favorable Environment Bacillus Early instar See label thuringiensis caterpillars instructions kurstaki (beneficial bacterium) Trichogramma spp. Caterpillars, including European corn borer, cutworm, and imported cabbageworm Moderate temperatures (not mid-day sun or cold mornings) Characteristics Bacterium must be ingested by insect. Release when first see flight of moths whose caterpillars damage crops. Comments Only kills larvae. Feed on the eggs of many species. Night releases may slow dispersal. Fungus Gnats Biological Control For Fungus Gnats Beneficial organisms attack only insects in moist substrate or borer tunnels; as a result, be careful not to allow the environment to dry out. Apply as a spray concentrate or a moist granular carrier (Table 7.4). Beneficial (entomopathogenic) nematodes Entomopathogenic nematodes are microscopic, multicellular, worm-like organisms. Three species of entomopathogenic nematodes, Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacteriophora, are used to control the larvae of fungus gnats. Several suppliers now market nematodes for use in the greenhouse and nursery (Exhibit, Scanmask, Vector, and Guardian are examples of several brand names). In trials conducted by University of Maryland Extension, S. feltiae was found to be the most effective of the three nematodes. Commercial availability of S. feltiae is currently limited to a few sources, but the costs of nematode application are now competitive with the costs of using many conventional insecticides. The moist environment of greenhouse media is ideal for entomopathogenic nematodes. Apply the nematodes as a media drench and to soil below the bench. Once applied to the potting substrate, the nematodes search for soil-inhabiting insects. When they locate an insect, they enter it. Once inside the host, the nematodes release bacteria into the insect s bloodstream. The bacteria multiply, and the nematodes feed on the bacteria. The insect then dies of bacterial infection. 50

60 In the greenhouse potting substrate, these nematodes complete their life cycle within the infected host in a few days. Large numbers of infective-stage nematodes are produced from each dead insect. These nematodes then leave the dead insect and move into the substrate in search of new insects to attack. Entomopathogenic nematodes and their associated bacteria have been tested extensively for toxicity to nontarget organisms. Research has shown that they are harmless to humans, wildlife, fish, and plants. Beneficial mites Stratolaelaps scimitus (=Hypoaspis miles) (=Geolaelaps miles) are tiny predatory mites native to the United States. They commonly inhabit the upper layers of soil. The mite is 0.5 millimeters (1/50-inch) long and light brown and has eight legs. Stratolaelaps feed upon a variety of microscopic soil-inhabiting insects and mites. They are well adapted to moist conditions and will survive in greenhouses in a variety of growing substrate throughout the year. In greenhouses, S. scimitus has been used to control fungus gnat larvae. It is also reported to contribute to the control of thrips by feeding primarily on the thrips pupating in the soil. Like most biological control agents, S. scimitus should be applied when the fungus gnat population is low. It is best to apply the mites to the substrate within the first few weeks after planting. Stratolaelaps populations include both sexes, but the males are much smaller and rarely seen. Using a hand lens with 10x to 15x magnification, you should be able to see the nymphs and adults of the mites which move rapidly across the soil surface. The mites reproduce in the greenhouse environment, completing their life cycle in 7 to 11 days. Barring the application of a soil-drench insecticide, the mites should not need to be reintroduced into the crop after the initial release. S. scimitus are usually supplied in a pasteurized sawdust mixture in 1-liter containers generally containing about 10,000 mites. Containers have shaker lids to ease distribution over the soil. Use mites immediately because they do not store well. You can examine the mites for viability by shaking a small amount of sawdust onto a sheet of paper and examining it with a hand lens. If present and healthy, nymphs and adults should move rapidly. Numerous eggs are included in these shipments and will survive poor shipping conditions better than the adults. Therefore, sprinkle them on the soil even if you do not see active forms. According to research on greenhouse-grown vegetables in Europe, appropriate mite release rates for tomatoes grown in in-ground beds are 5 to 8 mites per square foot of greenhouse space. For floriculture production, in which plants are grown in market packs, pots, or hanging baskets, exact release rates have not been determined. We suggest a rate of 10,000 mites per 1,000 square feet of greenhouse. It is easiest to mix the mites in the soilless substrate just before you fill the pots or container. Stratolaelaps are compatible with releases of beneficial nematodes or the use of Bacillus thuringiensis var israeliensis. Limestone or copper sulfate applied to the soil may reduce the S. scimitus population and should be avoided. The use of S. scimitus in the greenhouse environment is relatively new, and it has not been thoroughly tested for sensitivity to specific fungicides. Generally, foliar sprays should be less harmful than soil drenches. Bacillus thuringiensis Bacillus thuringiensis var israeliensis (Bti) is a highly effective spore-forming bacterium that produces a toxic protein crystal that kills maggots in the fungus-eating gnat families. Bti is produced by fermentation, a process similar to that used in manufacturing natural antibiotics. An organism commonly found in nature, this insecticide poses no danger to greenhouse workers, and there is no reentry restriction time. Greenhouse use Bti formulations are sold under the trade name Gnatrol and applied as drenches. Treat soil in pots, market packs, and areas beneath benches. Treatment for severe infestations requires the higher rates at 3- to 5-day intervals. Obtain season-long control through a weekly maintenance treatment at a lower rate. 51

61 Table 7.4 Biological Control of Fungus Gnats and Shore Flies Beneficial Target Pest Favorable Environment Dalotia Sciarid fly larvae, Adapt well to (=Atheta) shore fly larvae, assorted growth coriaria fungus gnat larvae media (including (predatory (Also thrips pupae) rock wool and beetle) coconut fiber) and capillary mats; do not survive freezing or flooding. Bacillus thuringiensis israelensis (Bti)- Beneficial bacterium (Gnatrol) Stratolaelaps scimitus (=Hypoaspis miles) (predaceous mite) Steinernema carpocapsae (Ecomask) Steinernema feltiae (Nemasys) Fungus gnat larvae Fungus gnats, shore fly larvae, (Also thrips pupae and springtails) Apply with adequate water to wet soil surfaces. Do not refrigerate. Characteristics Can be applied along with other predators. Apply as a soil drench to kill the larval stage. Soil-dwelling predaceous mite. Adults: tiny brown mite; lay eggs in the soil. Fungus gnats F Mobile; actively seek out their prey if temperature and humidity are right. Carry insectpathogenic bacteria in their gut. Fungus gnats, shore flies, root maggots Substrate needs to be moist. Comments Kills all immature life stages including eggs. Only kill larvae. Larvae must ingest; will stop feeding immediately and die within ~24 hours. Three applications at 7-day intervals are necessary. OMRI certified. Release rate: 45 to 100 per yd 2 ; one per season (rate determined by greenhouse size and pest infestation). Refrigerate until use. Apply as a soil drench. Keep nematode suspension agitated. Water plants before and after application. Apply early or late in the day. Need protection from desiccation, the sun, ultraviolet radiation, and temperature extremes. Infected insects turn brownish-yellow and usually die within 1 or 2 days. Only kill larvae. Available in a very fine clay formulation. 52

62 Mealybug Biological Control For Mealybugs Natural enemies are available for controlling mealybug species that occur in conservatories or greenhouses with specialty ornamental crops (Table 7.5). The combination of the mealybug destroyer (a lady beetle), Cryptolaemus montrouzieri, and the parasitic wasp, Leptomastix dactylopii, is effective against citrus mealybug, Planococcus citri, which is the most common mealybug in greenhouses. Table 7.5 Biological Control of Mealybug Beneficial Target Pest Favorable Environment Chrysoperla Mealybugs,aphids, carnea (green immature scales, lacewing) thrips, spider mites, immature whiteflies Cryptolaemus montrouzieri (mealybug destroyer) Leptomastix dactylopii (wasp) Mealybugs (also aphids, whiteflies, scales) Citrus mealybugs (not long-tailed mealybug). Characteristics Feed on immature eggs and pests. Larvae are cannibalistic F Both larvae and adults feed on mealybugs. Best control when mealybug population is high. Comments Disperse well. Release 2 12 larvae per yd 2. Avoid residual pesticides for at least one month before release. Release 2 per m 2 of infested area or 5 per infested plant. Mites: Broad Mites, Cyclamen Mites and Spider Mites Biological Control for Broad and Cyclamen Mites and Spider Mites Choose the predatory mite species best suited to the environmental conditions and pest mite species present in your greenhouse (Tables 7.6 and 7.7). Consult an Extension entomologist or biological supplier to be sure to get the correct species for each pest mite situation. Start releases soon after the first sign of spider mites. On crops or in greenhouses where mites have been a problem in the past, release the predaceous mites while plants are still small. Place predators directly onto infested leaves. Predatory mites are shipped mixed in grain or vermiculite so they can be easily distributed throughout the greenhouse. Most organophosphate, carbamate, and pyrethroid insecticides are toxic to predatory mites. Using Banker Plants for Twospotted Spider Mite Control One of the major mites damaging plants in greenhouses is twospotted spider mite. A biolgoical control option is to raise field corn plants in pots and infest the foliage with Banks grass mites that only feed on monocots such as corn and grasses. Once the mite population is established, release two predatory mites, Amblyseius californicus and Phytoseilus persimilis on the corn plants. The two predatory mites feed on the grass mites, reproduce and when the banker plant is moved into the greenhouse, they migrate off the corn and search for spider mites on plants in the greenhouse. Grass mites are found in many states, but as of late 2015, a permit from APHIS is pending. Permits will be required by the states as well. Availability is expected in

63 Table 7.6 Biological Control of Broad and Cyclamen Mites Beneficial Target Pest Favorable Environment Characteristics Comments Amblyseius barkeri Broad mites A. californicus can Apply early in crop A. californicus Neoseiulus cucumeris (=Amblyseius) (predatory mites) survive long periods without prey. cycle; 10 to 30 per plant. Neoseiulus cucumeris (=Amblyseius) (predatory mite) Cyclamen mites Release 2-10 per ft 2 of growing area. Table 7.7 Biological Control of Spider Mites Beneficial Target Pest Favorable Environment Characteristics Amblyseius fallacis Twospotted spider F Shiny body with (predatory mite) mites few hairs. Feltiella acarisuga (predatory midge) Galendromus occidentalis (predaceous mite) Amblyseius californicus (predaceous mite) Phytoseiulus persimilis (predaceous mite) Twospotted spider mites, carmine spider mites, European red mites Spider mites, European red mites Twospotted spider mites, broad mites, cyclamen mites Twospotted spider mites, carmine spider mites F Minimum relative humidity: 50% F Minimum relative humidity: 60%. Tolerates high temperatures and low humidity F Minimum relative humidity: 60%. Larvae are creamy yellow-brown; larval stage feeds on spider mites. Consumes pollen and honeydew and are also cannibalistic. Adults are strawcolored, fastmoving, dropletshaped with short legs. Eggs are oblong, transparent, and attached to hairs along leaf veins. Comments When prey level is low, it leaves the area to search for more food. Cocoons found along leaf veins. Resistant to organophosphate insecticides. Starvation-resistant. Can survive longer in the absence of prey (feeds on other mites and pollen). Sprinkle onto leaves. Consumes fewer spider mites than P. persimilis. 54

64 Scale Biological Control For Scale Natural enemies are commercially available for controlling scale species that occur in conservatories or greenhouses with specialty ornamental crops (Table 7.8). The parasitic wasp, Metaphycus helvolus, is effective against the hemispherical scale, Saissetia coffeae, and useful against soft brown scale, Coccus hesperidum. Table 7.8 Biological Control of Scale Beneficial Target Pest Favorable Environment Aphytis melinus (wasp parasite) Metaphycus helvolus (wasp parasite) Armored scales, oleander scales, California red scales, yellow scales Soft scales, brown soft scales, black scales, nigra scales, hemispherical scales Characteristics F Adults are tiny yellow wasps that lay eggs under the covering of midsized scales F Adults are tiny black/yellow wasps. Comments Before release, wash off or use a 1% solution of insecticidal soap to reduce honeydew. Lay eggs on newly hatched crawlers and also feed on older scale. 55

65 Thrips Biological Control For Thrips Various predators and a biofungicide are available for thrips control (Table 7.9). Two species of predatory phytoseiid mites, Neoseiulus (=Amblyseius) cucumeris, and Iphiseius (=Amblyseius) degenerans, appear to be well suited for controlling immature thrips preying on greenhouse crops. Similar to thrips, these mites prefer small niches where contact between predator and prey is likely even without specific searching. These predators are pollenphagous (pollen feeding) when thrips populations are low. More questions remain to be answered about the best timing and frequency of releases and usefulness of these predators on various crops and on various thrips species. These mites must be introduced before a thrips population has built up to damaging levels. The mites establish themselves on leaves, usually on the undersides, and are most effective in attacking young (1st instar) larvae of thrips. The mites use their chelicerae to pierce the thrips and suck out the cellular fluids. The predaceous mites will establish themselves on a crop in the greenhouse and then mate and reproduce. The major limitation of their use is that these mites are susceptible to many insecticide sprays; growers must use biological control against other pests or be selective in pesticides used, selecting insect growth regulators or using biorational chemicals that have minimal impact on predators. Note that the beneficial pathogen, Beauveria bassiana GHA strain (BotaniGard), does not affect phytoseiid mites and could possibly be used in combination with beneficial mite releases. Apply predatory mites with shaker bottles. Growers shake the mites and a grain carrier onto the crop. Another option is to apply the mites using paper sachets. Hang the sachets on plants or on marker stakes. An adult N. cucumeris feeds on one thrips per day during its 30-day life. For releases during the short days of winter the best choice is I. degenerans. Alternatively, obtain N. cucumeris from biological suppliers that carry selections that do not go into diapause in winter. If using predaceous mites for controlling western flower thrips, it is essential to combine this treatment with INSV-monitoring plants or use on-site INSV serological testing kits. The release rates for N. cucumeris range from 90 to 270 per yd 2 of growing area for floriculture crops. If using mite sachets we have found that 60 sachets (with 50 mites per sachet) placed in 3,000 square feet generally provide good control for 5 6 weeks. Replace the sachets when a new crop is placed in the greenhouse. Predatory true bugs - There are about 70 species of predatory true bugs in the genus Orius, minute pirate bugs. Three species are generally available from commercial insectaries for thrips control: O. insidious (insidious flower bug), O. tristicolor (minute pirate bug), and O. albidipennis. Pirate bugs are voracious, reproduce well in greenhouses, and may provide the best thrips control because they are able to attack all stages of thrips, including adult thrips. In floriculture crops apply 2 6 Orius per square yard of production area. Using Banker Plants with Orius - One of the methods for thrips control is to use the predator called minute pirate bug (Orius sp). The most effective way to use the Orius bugs is to grow banker plants. Use ornamental peppers as the banker plants and release the Orius on them. The Orius you purchase will feed on the pollen of the ornamental pepper plants and will lay eggs into the foliage. The hatching nymphs will also feed on the pollen and thrips, if present. The maturing Orius adults migrate across your greenhouse searching for thrips nymphs (1 st and 2 nd instars) and adults. Keep in mind that peppers are a warm season crop and take a long time to get going in winter. You need to start your plants in January to get them up to size by March when you release the Orius bugs. Ontario, where it is much further north, they start the peppers in late November to December. Researchers in Ontario have found that Pepper Purple Flash produces abundant pollen and is an excellent banker plant on which 56

66 Orius will lay eggs. Release Orius insidious in late March to early April. The Orius arrive in lots of 100 adult per container (cost is around $40 per 100). Release at the rate of 5 Orius (minute pirate bugs) per 20 pepper plants. Since Orius are a little pricy the idea is to get them to reproduce on banker plants so you can keep your order for more Orius limited. Most growers use between 5-10 banker plants of Pepper Purple Flash per acre of growing area Beneficial pathogens - Several pathogens have been investigated for controlling thrips. The entomopathogenic fungus, Beauveria bassiana, applied as a fine mist spray directly onto thrips, is used to control western flower thrips in greenhouses. Some growers use Beauveria bassiana in combination with insecticides to improve the control of thrips. The entomopathogenic fungus, Metarhizium anisopliae, is probably one of the more promising biological controls for thrips control. When spores land on thrips, the spores break through the insect s exterior to the inside, using enzymes and mechanical force. The insect dies within a few days. 57

67 Table 7.9 Biological Control of Thrips Beneficial Target Pest Favorable Environment Amblyseius Thrips F; tolerates degenerans low humidities (predatory mite) Amblyseius swirskii (predatory mite) Beauveria bassiana (entompathogenic fungus) Chrysoperla spp. (green lacewing, predator) Stratolaelaps scimitus (=Hypoaspis miles) (predatory mite) Neoseiulus (=Amblyseius) cucumeris (predatory mite) Orius insidiosus (predaceous bugs) Good for chili thrips Thrips (and whitefly, aphids, mites and mealybugs) Thrips (aphids, mealybugs, immature scales, spider mites immature whiteflies) Thrips (fungus gnat larvae, shore fly larvae, and springtails) Western flower thrips, onion thrips (twospotted spider mites and eggs, broad mites, cyclamen mites) Thrips preferred (also feed on mites, aphids, scales, whitefly pupae, and softbodied arthropods [spiders]) Begins development at F Humidity above 60 % Do not refrigerate F. Minimum relative humidity: 60% F. Long days. 58 Characteristics Highly mobile predaceous mite. Not susceptible to diapause so can introduce in winter. Naturally occurring fungus in soils. Feeds on immature eggs and pests. Larvae are cannibalistic. Soil-dwelling. Adults are tiny and brown and lay eggs in the soil. Adults are fastmoving, teardropshaped, and tan. Females consume an average of one thrips per day over a 30-day life span. Eggs are transparent white on leaf hairs along veins or leaf underside. Alternate food sources are fungi, honeydew and pollen. Attacks thrips eggs and immatures. Nymphs are yellow with red eyes. Adults and nymphs are predaceous bugs. Adults are black and attracted to flowers and can eat 5 20 thrips per day. Comments Also feeds on pollen. Tolerant of high temperature. Repeated application with fine mist. Disperse well. Release 2 12 larvae per yd 2. Release per yd 2 according to pest population and greenhouse size. Mites are found on the underside of the leaves near the mid-vein. Release between predators per plant. Release before or soon after the first thrips are found. Adults and nymphs shipped in sachets and bottles, flower mites, and bran. Repeat applications are necessary. Go dormant during short days (need supplemental lighting to extend day September to April). Release 1/10 ft 2 as a preventative or 1 per 2 ft 2 if thrips present.

68 Whitefly Biological Control For Whitefly Whiteflies are common pests of some greenhouse ornamentals, tomatoes, and cucumbers. Chemical control is difficult because the eggs and immature larvae have a waxy coating that resists chemicals. Whitefly populations have also developed resistance to commonly used pesticides, even to the recently introduced synthetic pyrethrins. Whitefly adults are found at the top of the plant or on the leaf underside. Plant damage is seen as yellowing of the foliage beginning around the midvein. Parasitoids and pathogens are commercially available for whitefly control (Table 7.10). Parasitoids Two parasitoids that have been used successfully to control whitefly on greenhouse crops are tiny wasps of the Encarsia and Eretmocerus species. These wasps attack whitefly nymphs (not adults), killing them in one of two ways. The first attack method is when the female wasp uses her needlelike ovipositor to lay an egg within or beneath a whitefly nymph. Encarsia sp. prefers the third to fourth instar whiteflies. The egg hatches and the parasitoid larva feeds on the whitefly nymph. Wasp pupation occurs within the nymph. When the adult wasp emerges from the whitefly pupa, it chews a round exit hole through the cuticle at one end of the whitefly pupa. The other way wasps attack whitefly nymphs is through a phenomenon called host feeding in which the female wasp punctures the whitefly nymph with her ovipositor, killing the nymph, and then she feeds on the fluids that exude from the wound. For whitefly control on short-term floral crops, these wasps are usually released weekly in large quantities. When wasps inundate the pests, the wasps kill whitefly nymphs primarily by host feeding rather than parasitism, leaving behind dead whitefly nymphs that appear collapsed and dry. Several species of whitefly parasitoids occur naturally in the U.S. and they may migrate into unsprayed greenhouses and attack whiteflies. However, the degree of control provided by these parasitoids is usually insufficient. Repeated releases of commercially reared parasitoids which augment the population are typically more effective. Encarsia formosa (Gahan) is a tiny wasp (0.6 mm) with a black head and thorax and pale yellow abdomen. Its wings are transparent. Females produce mostly other females; males are rare. Greenhouse whitefly pupae that have been parasitized by E. formosa turn black; Bemesia tabaci whitefly pupae turn amber brown. Adult wasps are rarely noticed and should not deter the sale of the plants. This parasitoid is widely used for biological control of greenhouse whitefly on greenhouse vegetables. Release rates vary from three to six wasps per square foot of growing area with repeated releases at 7- to 14-day intervals. E. formosa will reproduce on many greenhouse crops once populations are established. E. formosa is more successful at suppressing whitefly in summer than in winter. For maximum reproduction, wasps require a higher light intensity and warmer temperatures than the whitefly. The cost of E. formosa can be equal to foliar pesticide applications or slightly higher. Multiple releases of E. formosa are more expensive than a single application of a long residual systemic insecticide such as imidacloprid. Eretmocerus eremicus (=californicus) Rose and Zolnerowich is also a tiny wasp, but differs from Encarsia formosa in having an adult that is entirely yellow. These wasps have green eyes and clubbed antennae. Males have longer, more prominent antennae than females. Parasitized whitefly nymphs appear beige in color. Release rates are 2 3 per square foot of growing area. Repeated releases at 7- to 14-day intervals are often necessary. Eretmocerus will not reproduce on many greenhouse crops, so repeated applications are necessary until the whitefly population is reduced to a desired level. Unfortunately, this parasite is relatively expensive and costs significantly more to use to control whiteflies than applications of pesticides. 59

69 Pathogens A naturally occurring insect pathogen, Beauveria bassiana, is effective in controlling whiteflies, certain aphid species, mites, and thrips. Two different strains of the fungus are commercially available. BotaniGard (GHA strain), is formulated as a wettable powder and an emulsifiable suspension. Naturalis-O (JW-1 strain) is a flowable formulation. B. bassiana spores are formulated to mix readily in water and are applied using standard high-volume spray equipment. The fungus kills insects either by direct contact with the spray or through secondary contact with spores on foliage. When spores come in contact with an acceptable host, a germ tube penetrates the insect s cuticle and feeds from the host body, resulting in the death of the host. In most cases, it takes 8 to 10 fungal spores on an insect to cause fungal infection and subsequent death of the insect. The warm temperatures and relatively high humidity in greenhouses present an ideal environment for using this fungal pathogen. Because fungal spores kill insects through direct contact, good spray coverage is essential for achieving adequate control. Table 7.10 Biological Control of Whiteflies Beneficial Target Pest Favorable Environment Beauveria Whiteflies (and Humidity above bassiana thrips, mealybugs 60 % (beneficial fungus) and aphids) Delphastus pusillus (lady beetle) Encarsia formosa (wasp parasitoid) Eretmocerus eremicus (wasp parasitoid) Eretmocerus mundus (wasp parasite) Greenhouse whiteflies, sweet potato whiteflies, Bemesia tabaci whiteflies Greenhouse whiteflies Sweet potato whiteflies, Bemesia tabaci whiteflies Sweet potato whiteflies, Bemesia tabaci whiteflies Characteristics Naturally occurring fungus in soils F Adults are minute black lady beetles that eat whitefly eggs, larvae, adults. Above 70 F; 70 % relative humidity (If temperature is below 62 F, wasps will not fly). Adults are tiny wasps that develop faster than the whitefly. Adults lay eggs in immature stages of whitefly, parasitizing and killing them F Adults are tiny wasps that lay their eggs under whitefly larvae. Adapts to both high and low temperatures. Adults: tiny wasps; lay their eggs under whitefly larvae. Comments Repeated applications with fine mist. Require whitefly eggs per day to maintain egg-laying. Consume settled whiteflies per day. Shipped inside blackened whitefly scales attached to cards. Attach cards to the foliage. Release at first sign of whiteflies on yellow sticky cards. Release rate: 3 4 releases with 1- to 2 week intervals. Release rate: 3 5 releases with 1- to 2 week intervals. Make a minimum of 3 releases. 60

70 Chapter 8 Biopesiticides and Reduced-Risk Pesticides Stanton A. Gill, Extension Specialist Introduction Biopesticides are types of pesticides derived from such natural materials as animals, plants, bacteria, fungi, and certain minerals (Table 8.1). Examples include entomopathogenic nematodes used for fungus gnat control and potassium bicarbonate which acts as a pesticide against powdery mildew. Biopesticides (also known as biological pesticides) are pesticides derived from natural materials. There are four types. Microbial pesticides contain microorganisms that function as biological control agents, such as fungi, bacteria, viruses or related organisms (e.g., spinosad). These highly selective materials have activity against specific target insect or mite pests. Botanicals are naturally occurring plant-derived substances (extracts, essential oils, potassium bicarbonate, hydrogen dioxide, phosphorous acids, etc.) that affect the central nervous system, the mitochondria electron transport system, or act as insect growth regulators. Many essential oil pesticides exhibit broad-spectrum activity against insects and mites due to multiple modes of action, (e.g. antifeedant, molting and respiration inhibition, growth/reproduction reduction, etc.). Biochemical pesticides are naturally occurring substances are designed to control or regulate insect pest populations by non-toxic mechanisms, such as pheromones (e.g., sex, aggregation and alarm), mating disruption, monitoring and lure-and-kill strategies that control pests. Plant-incorporated protectants (PIPs) are substances plants produce based on genetic material (added to them through genetic engineering) that render plants immune or tolerant of insect and mite pests. Why Growers Should Use Biopesticides Biopesticides are usually inherently less toxic than conventional pesticides. Most nursery and greenhouse operations have workers constantly entering the growing area to water, move plant material, fertilize, or conduct other plant maintenance chores. Most pesticides have a required Re-entry Interval (REI) that restricts employees from entering a greenhouse or nursery area unless they are wearing the Personal Protective Equipment (PPE) required on the label. This adds time and additional expense to the nursery or greenhouse operation. Biopesticides generally have REIs of only 4 to 12 hours. Some biopesticides such as entomopathogenic nematodes have no REI. Growers who can control insects or diseases by selecting an effective biopesticide with minimal or no REI will save time in labor. Not needing PPE equipment makes the selection highly attractive. It also makes sense to use biopesticides in residential and commercial landscapes where there is an increasing demand for least-toxic pest control methods as part of an Integrated Pest Management (IPM) approach. Re-entry intervals are not presently used in landscapes. The disposal of leftover biopesticides is less restrictive than the disposal of more toxic compounds which is an additional benefit. Biopesticides often decompose quickly, thereby resulting in lower environmental and human exposure. Pollution problems caused by conventional pesticides are largely avoided. The disposal of old pesticides, which currently creates problems for growers, will likely be an expensive and major problem for greenhouse and nursery growers and landscape managers in the near future. Biological control has been used only in a limited manner in the nursery, greenhouse, and landscape industries. Biopesticides will help managers make the transition to using beneficial organisms relatively 61

71 smooth. Biopesticides generally affect only the target pest and closely related organisms in contrast to broad spectrum, conventional pesticides. Many of the biopesticides can be used in combination with biological releases to control insect or mite pests. Biopesticides used to control fungi often have to be pre-incorporated into substrate or inoculated early in the growth stages of a plant. Biopesticides are the trend of the future. Generally, they pose fewer risks to the environment and to workers than conventional chemicals. When a pesticide is registered with the Environment Protection Agency, EPA generally requires less data about a biopesticide than it does about conventional chemicals. Biopesticide registration also generally takes less time an average of less than one year compared to at least three years. Chemical companies, well aware of the cost savings, are working on several new biopesticides that should be registered during the next decade. Companies registering a new pesticide must submit a variety of data about its composition, toxicity, and degradation to the environment before it is approved for use. Three Main Categories of Biopesticides Microbial Pesticides Microorganisms, including bacterium, fungus, and virus, are the active ingredient of microbial pesticides. Some microbials control plant pathogens, usually on a preventative basis, and some control insects and mites. In some cases the microbial insecticide may be specific, such as Bacillus thuringiensis Serotype H14 (Bti), which controls fungus gnat larvae and mosquito larvae. Others, such as the fungus, Beauveria bassiana, control several species of insects including whiteflies, aphids, and some caterpillars. The most widely known microbial pesticide is Bacillus thuringiensis (Bt), which is used to control a variety of earlystage caterpillars. Reduced-Risk Pesticides Starting in 1993 the federal EPA has expedited the registration of conventional pesticides with the following characteristics: very low toxicity to humans and nontarget organisms including fish and birds, low risk of groundwater contamination or runoff, low potential for pesticide resistance, and a demonstrated efficacy and compatibility with IPM. EPA refers to materials meeting these criteria as reduced-risk. The reduced-risk designation applies only to certain uses of a particular pesticide which may not include all label uses for that product. Reduced-risk products/uses must be registered with EPA and labels will bear EPA registration numbers. Manufacturers, however, are not permitted to label materials as reduced-risk. Floramite (EPA# ) miticide and Endeavor (EPA# ) insecticide are two reduced-risk pesticides labeled for use on ornamentals. Fenpyroximate (Akari 5SC) from SePRO Company is a reducedrisk miticide. Tebufenozide (Confirm), from Dow AgroSciences, an insect growth regulator (IGR) for caterpillars, is also a reduced-risk pesticide for ornamentals. Some insecticides such as spinosad (Conserve) are considered reduced-risk for certain non-ornamentals applications only. Conserve is not presently classified as a reduced-risk pesticide. Other reduced-risk pesticides for use on ornamentals include Heritage Fungicide ( ) for turf; Subdue GR ( ), Subdue 2X WSP ( ), and Subdue Maxx ( ) for ornamentals; and Compass Fungicide ( ) for ornamentals. Minimum-risk pesticides are certain products exempted from EPA registration (and therefore carry no EPA registration number), containing only active ingredients outlined in FIFRA 40 CFR (g) ( the 25b list ) and inert ingredients currently identified on Federal Register Notice 59 FR ( the 4A list ). The lists can be seen on the web at inerts2003list4a-cas.pdf. Biochemical Pesticides Biochemical pesticides are naturally occurring substances that control pests. Materials such as insecticidal soap, composed of fatty acids, alcohol, and water, are good examples of a biochemical. Empower, a garlic 62

72 extract, is an insect repellent that can be used to flush cryptic insects such as thrips out of tight, hard-topenetrate areas on the plants. This biochemical is often used in combination with a contact material that kills the thrips once they are in the open. Because it is sometimes difficult to determine whether a substance meets the criteria for classification as a biochemical pesticide, EPA has established a special committee to make such decisions. In 1994 the Biopesticide and Pollution Prevention Division (BPPD) was established in the Office of Pesticide Programs to facilitate biopesticide registration. For updates on new biopesticides check the following website: Living organisms are not regulated by EPA and include entomopathogenic nematodes, beneficial mites, and insects. 63

73 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses Chemical Name Abamectin Azadirachtin Bacillus thuringiensis supsp. Kurstaki: Trade Name/ Common Name Avid 0.15EC Ardent 0.15 EC Merlin Lucid Minx Azatin XL Aza-Direct AzaSol Azera Bonide neem oil concentrate Molt-X Neemix 4.5 Ornazin Triact 70 Biobit HP; Diliver, Dipel Pro, Javelin WG, Thuricide Application Method Foliar spray application Foliar spray application Foliar spray application Foliar spray application Foliar spray application Foliar spray application Foliar spray application Type of Biopesticide REI (hrs) Pest and Usage Microbial 12 Foliar contact action with translaminar properties. Do not get in eyes, on skin, or on clothing. Avoid breathing spray mist. For aphids, mites, leafminers, thrips whiteflies. Toxic to bees. Botanical 4 IGR. Works best on immature insects. Feeding deterrent for some insects. Botanical 4 IGR. Works best on immature insects. Botanical 4 IGR. Can use on ornamentals, vegetables, and herbs. Botanical 12 IGR. Can use on ornamentals, vegetables, and herbs. Botanical 12 Works best on immature insects. Microbial 4 Labeled for herbs, greenhouse ornamentals, vegetables, and interiorscapes. No impact on beneficial organisms Works only on small, early instar caterpillars. Must be ingested to be effective so thorough coverage is essential. Insects stop feeding and die 1-5 days later. Can apply through irrigation system. Do not combine with fungicides or fertilizers containing copper or chlorine. 64

74 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Bacillus thuringiensis Serotype H 14 (=var. israelensis) Bacillus thuringiensis subsp. aizawai Beauveria bassiana BotaniGard ES, BotaniGard 22WP, Mycotrol O Trade Name/ Common Name Application Method Type of Biopesticide REI (hrs) Pest and Usage Gnatrol Soil drench Microbial 4 For mosquitos, black application flies, and fungus gnat larvae. Apply to young (early instars). Stomach poison - must be ingested to be active. Needs 3 applications at 7-day intervals for best efficacy.can apply in irrigation systems. Do not combine with fungicides or fertilizers containing copper or chlorine. Organic certification. XenTari Microbial 4 For armyworms, Heliothis loopers, saltmarsh caterpillars. Stomach poison so must be eaten by target insect to be effective. Herbs. Treat when larvae are young. Larvae must be actively feeding on treated, exposed plant surfaces. Insect stops feeding and dies 1 to 5 days later. Apply to foliage and insect as a fine mist at 3- to 5-day intervals. Microbial 4 Treat before high insect populations develop. It takes 3 to 7 days for insects to die. Must make at least 3 applications at 7-10 day intervals. Repeated sprays usually necessary. 65

75 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Bifenazate Floramite Foliar application Bifenazate + Abamectin Chromobacterium subtsugae strain PRAA4-1 Sirocco Grandevo Foliar application Foliar application 66 Type of Biopesticide REI (hrs) Pest and Usage Reduced-risk 12 For spider mites only: pesticide twospotted, pacific, citrus red, strawberry, European red, southern red, spruce spider, bamboo spider, and Lewis. Labeled for greenhouse ornamentals and interiorscapes day control. Also has ovicidal control. Minimal impact on beneficial mites. Reduced-risk 12 For leafminers and pesticide mites (broad, twospotted, bud, cyclamen, European red, Lewis, rust, southern red, spruce); Suppresses aphids, thrips, whitefly. Contact and translaminar insecticide for quick mite knockdown and control. For non-food crops. Thorough coverage of foliage is essential; Must contact young immatures with spray. Biological 4 For greenhouse herbs. Contact biological stomach poison for young immature stages of foliar feeding insects and mites. Reduces adult egg laying. Proper timing targeting newly hatched larvae is important. Temporarily repels honey bees for up to 4 to 6 days after spraying. See label if tank mixing.

76 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Cyflumetofen Sultan Foliar application Cyromazine Citation 75WP Foliar or drench application Cyanoaniliprole Mainspring Foliar or soil application Diflubensuron Adept Soil drench or coarse spray Type of Biopesticide Insect growth regulator REI Pest and Usage (hrs) 12 Contact; for spider mites only. Thorough coverage of all plant parts is important. Do not apply if rain or irrigation event is expected within 1 hour following application. Compatible with most biological control organisms used for mite control. 12 For control of fly (Dipterous) leafminers, shoreflies, and fungus gnats. For immatures only; will not kill adult insects. Mandatory rotation details on label. 12 Both contact and systemic activity. Apply only to vegetable transplants grown in enclosed structures. Toxic to bees. 12 Labeled for most greenhouse ornamentals and interiorscapes. For caterpillars, leafminers, whitefly, fungus gnat, and shore fly larvae. Disrupts normal molting processes of insect larvae. Do not apply to poinsettia, hibiscus or Reiger begonia. Do not reuse treated potting substrate. 67

77 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Application Type of REI Pest and Usage Common Name Method Biopesticide (hrs) Etoxazole Tetra-San Beethoven TR Foliar application Fogger Mite growth regulator 12 4 Labeled for all greenhouse ornamentals and interiorscapes for spider mites only. Translaminar; controls egg and nymph stages (will not kill adult mites). Do not apply to poinsettia after bract formation. Beethoven also suppresses whitefly. Fenoxycarb Preclude TR Fogger IGR 12 Total release cans for greenhouse use only. For aphids, caterpillars, leafminers, mealybugs, mites scales, thrips, weevils, and whitefly. Fenpyroximate Akari Foliar Reduced-risk 12 For greenhouse application pesticide ornamentals, tomatoes, cucumbers and interiorscapes only. Labeled for control of mites, leafhoppers, psyllids, mealybugs, and whitefly. Long 21- to 24-day mite control. Immediate cessation of feeding and egg laying. Minimal impact on beneficial mites. 68

78 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Type of Biopesticide Hexythiazox Hexygon Insect growth regulator Horticultural oil FERTI-LOME horticultural oil spray; Golden Pest Spray Oil; Lesco Horticultural Oil #019492,; Monterey Horticultural Oil; JMS Stylet Oil; PureSpray Green; RTSA Horticultural Oil; Saf-T-Side oil; SuffOil-X, Ultra- Pure Oil; Tri-Tek Apply to foliage and directly to insect. REI Pest and Usage (hrs) 12 For spider mite eggs and immatures. Apply before adult mite build-up. Control is from direct contact with spray or contact with treated plant surfaces. Controls motile stages, newly deposited mite eggs and eggs laid after product applied. Adult mites are not directly affected. Product has some residual activity. Biochemical 4 Contact insecticide; No residual control. Thorough coverage is very important. Be cautious on open blooms. Foliar injury may occur if applied during hot, humid conditions. Do not tank mix with more than 1 pesticide. Do not apply through irrigation systems. Do not spray more than once per week. Do not spray when there is moisture deficit in leaves or the plant is under stress. Test for phytotoxicity before treating. Do not exceed 4 applications per growing season. Do not use with products containing sulfur or carbaryl (Sevin). 69

79 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Application Type of REI Pest and Usage Common Name Method Biopesticide (hrs) Insecticidal soap (Potassium salts of fatty acids) Insectidal Soap (Bayer, Bonide, Earth-Tone, Safer, other brands) DES-X M-Pede Foliar application Do not use on open blooms, transplants, or root cuttings. Biochemical 4 Labeled for most greenhouse ornamentals, herbs, and interiorscapes. Compatible with biological control agents. Must contact insect or mite. No residual control. Do not apply when temperatures exceed 90 F. Do not treat blooms, transplants, or root cuttings. Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) NOFLY WP Foliar application Biological 12 A naturally occurring fungus that infects and kills whiteflies, thrips, aphids, mites, and other insects. It is not toxic to humans. The fungus takes 3-7 days to infect and kill the pest. Works best at temperatures between 72 F-86 F; requires high humidity. May cause moderate eye irritation. Kinoprene Enstar AQ IGR For whiteflies, scales, leafminers, fungus gnats, mealybugs, thrips, aphids, and mites. Thorough coverage is necessary. Some rose varieties roses show delayed damage. Metarhizium anisopliae strain F52 Met 52 Foliar application or drench or foliage and root plant dip 70 Biological For greenhouse/ nursery. Contains spores of the insectkilling fungus, Metarhizium. Insects that come into contact with the spores will become infected.

80 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Type of Biopesticide Meth-oxyfenozide Intrepid 18 Insect Growth Regulator Nematodes, beneficial - Entomopathogenic: Steinernema feltiae, Steinernema carpocapsae, and Heterorhabditis bacteriophora Nemasys, Entonem, Millenium NemaShield, ScanMask REI Pest and Usage (hrs) 4 For small caterpillars only. Begin applications when larvae are observed/ first sign of feeding damage. Uniform coverage of foliage is essential. Soil drench Biological Naturally occurring, insect-parasitic nematode seeks out fungus gnat larvae, enters their natural body openings, and releases symbiotic bacteria that kill the pests. Can be used as a preventive or a curative control. Apply as soon as possible after potting or placement in the greenhouse. Works best in soil at temperatures from F. Apply solution to moist soil or growing media. No known impact on parasites or predators. Substrate must be moist prior to application; follow up with irrigation. REI - EXEMPT Novaluron Pedestal Foliar spray Insect Growth Regulator Active only on immature stages by disrupting the molting process. Fully developed adult stages are not affected. Do not use product more than once within each generation cycle. Do not apply to poinsettia.

81 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Pymetrozine Endeavor Foliar application Pyriproxyfen Fulcrum Foliar, drench or sprench application Saccharopolyspora spinosa Conserve Judo Foliar application Type of Biopesticide Reduced-risk pesticide REI Pest and Usage (hrs) 12 Stops insect feeding within hours; insects remain on plants for 2 to 4 days. Has some residual activity; will control pests that move onto plant after spraying. Do not treat poinsettias after bract formation. 12 Controls eggs, nymphs/larvae and pupae. No adult control. Do not use low volume spray equipment to control soil-inhabiting insects such as fungus gnats and shore flies - apply as a sprench. See label for phytotoxicity. 4 For herbs, ornamentals, aquatics, and vegetables; caterpillars, leafminers, mites, shoreflies, thrips, sawfly larvae, and certain beetles. Variable control of mites. With unique mode of action, can use in in rotation with any other class of products Contact and stomach poison. Get thorough coverage of both leaf surfaces. For mites and whitefly only on greenhouse ornamentals. For all mite developmental stages; most effective on juveniles. See label for phytotoxicity. 72

82 Table 8.1 Biopesticides, Reduced-risk Pesticides and Their Uses (continued) Chemical Name Trade Name/ Common Name Application Method Spirotetramat Kontos Foliar, drench application Sulfoxaflor (IsoclastR) + Spinetorum XXPire WG Foliar application Tolfenpyrad Hachi-Hachi Foliar application 73 Type of Biopesticide REI Pest and Usage (hrs) 24 Contact, stomach poison, systemic and translaminar action. Provides knockdown and up to one month of residual control. Not for edible crops or geranium. Start treatments prior to establishment of high pest populations and reapply as needed. 12 Controls chewing and sap-feeding insects Has systemic and translaminar activity. Aphids, leaf feeding beetles, caterpillars, lace bugs, mealybugs, plant bugs, some scales (pine needle, cottony cushion), sawfly (EPS), shore flie, spider mites (suppreses spruce and two-spotted), thrips, and whiteflies. No significant impact on predators or parasitoids. After 3 hours for drying, risk to pollinators is greatly reduced 12 Contact insecticide. Controls all life stages (eggs, immatures, and adults) via contact and ingestion. Controls aphids, caterpillars, leafhoppers, scale, mealybugs, and thrips; suppresses whiteflies, Has shown anti-feeding activity. See label on phytotoxicity.

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84 Chapter 9 Understanding Insect Growth Regulators Stanton A. Gill, Extension Specialist What Is an Insect Growth Regulator? Insect growth regulators (IGRs) can stop the development of insects, and effectively kill them. To understand how an insect growth regulator works you must understand that arthropods, such as insects and mites, have an exoskeleton, which is a skeleton on the outside, made up of chitin. To grow, an insect or mite must shed its skin repeatedly throughout its youthful development. It also must change from an immature stage to a sexually mature adult. These processes are controlled by IGR juvenile hormones, chitin synthesis, and ecdysone production. The chemistry of how these insects form their exoskeleton and molt has been studied and materials have been developed that mimic these natural processes in the insect. Since birds, reptiles, and other animals including humans do not form chitinous exoskeletons we are not affected by these chemicals. Not all insect and mite growth regulators work on insects in the same way and they do not work on all pests. Table 9.1 Product Names and Distributors of Commonly Found IGRs for Greenhouse Use Brand Name Chemical Name Distributor Adept diflubenzuron UniRoyal Aza-Direct azadirachtin Gowan Company Azatin azadirachtin Olympic Citation cyromazine Syngenta Professional Products Confirm tebufenozide UniRoyal Distance pyriproxyfen Valent USA Corporation Enstar II kinoprene Wellmark International Hexygon hexythiazox Gowan Company Nemix azadirachtin Certis USA Ornazin azadirachtin SePRO Company Pedestal novaluron UniRoyal Precision fenoxycarb Whitmire Talus buprofezin SePRO Company Are All Insect Growth Regulators the Same? Not all IGRs are the same. We can group the growth regulators into three main classes: chitin synthesis inhibitors, ecdysome inhibitors, and juvenile hormone mimics. Below is a short explanation of how the IGR classes differ from one another, followed by a list IGRs that are commercially available (Table 9.2): Chitin synthesis inhibitors (Adept, Citation, Pedestal, Talus) disrupt molting by inhibiting chitin biosynthesis. Hexygon, the only mite growth regulator, falls under the class of chitin synthesis inhibitor. Although Hexagon is an ovicide, it controls newly laid eggs and eggs laid after application. Ecdysone inhibitors (Azatin, Ornazin) trigger molting in insects and interfere with the metabolism of molting hormones, preventing molting by indirectly disrupting chitin biosynthesis in larva and pupa. 75

85 Juvenile hormones (Confirm, Distance, Enstar II, Precision) imitate molting hormones causing a premature molting. This action determines whether the insect stays as a larva or moves into the pupal or adult stage. How Do Growers Manage Resistance? Repeated use of IGRs with similar modes of action may lead to the build-up of resistant insect strains. Be sure to rotate IGR use among the different classes of IGRs. It has been noted that insects and mites cannot development resistance to IGRs. When it comes to applying any constant pressure (e.g. sprays) to suppress a pest population, the biological world develops ways to mutate around material preventing its survival. When using IGRs for insect control select one of the chemicals from a class and use this product for one life cycle of the insect or mite. If you need to continue applications to control the pest after one life cycle, switch to another class. For example, if using Adept (chitin synthesis inhibitor), switch to Distance (juvenile hormone mimic). Do not rotate within a class. For example, if using Enstar II, do not switch to Distance. Table 9.2 Insect Growth Regulators And The Pests They Control Brand Name Pest Controlled Re-Entry Level Comments Adept Leafminers, armyworms, whiteflies, fungus gnat larvae, shore fly larvae 12 hours Rates are 2 oz/100 gallons water and 4 8 oz/100 gallons water, depending on the pest. Aza-Direct Azatin Enstar AQ Fulcrum Aphids, beetles, fungus gnats, caterpillars, psyllae, thrips, weevils, whiteflies Aphids, beetles, fungus gnats, caterpillars, psyllae, thrips, weevils, whiteflies Mealybugs, whiteflies, fungus gnat larvae Aphids, armored scales, fungus gnats Spotted tentiform leafminer, mealybugs, shore flies, whitefly (greenhouse, silverleaf, sweet potato) 76 4 hours The esters and fats have been removed which reduces the tendency of rancidity. Up to 3 year shelf-life. 4 hours Interferes with an insect s ability to molt. 12 hours Complete coverage of insect is essential. 12 hours For control of eggs, nymphs/larvae and pupae. Can apply as high volume spray or with low volume application equipment such as Electrostatic Spraying Systems or PulseFog systems. Do not use low volume equipment for soildwelling insects such as fungus gnats and shore flies; apply as a sprench for these pests. Phytotoxicity concerns.

86 Table 9.2 Insect Growth Regulators And The Pests They Control (continued) Brand Name Pest Controlled Re-Entry Level Comments Hexygon Immature spider mites 12 hours Good coverage is essential for control. Neemix Aphids, beetles, fungus gnats, caterpillars, psyllae, thrips, weevils, whiteflies 4 hours 1-year shelf life Ornazin Pedestal Talus Aphids, beetles, fungus gnats, caterpillars, psyllae, thrips, weevils, whiteflies, scales, and nematodes Thrips, caterpillars, leafminers, whiteflies Whiteflies, soft and armored scales, leafhoppers, mealybugs, fungus gnats, planthoppers, glassywinged sharpshooter 12 hours One difference between Azatin and Ornazin is the level of limonoids in the products. Limonoids are extracted from the neem seed coat. 12 hours Rates 6 8 oz/100 gallons water 12 hours Chitin synthesis inhibitor. Also reduces adult egg laying/egg viability. Rates from 9 to 21 oz/100 gal., depending upon pest. 77

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88 Chapter 10 Impact of Selected Pesticides on Bees Stanton A. Gill, Extension Specialist Insecticides and pollinators What is the problem? Pollinator health has been in the spotlight of popular media, some of the public, apiary specialists, and scientists. After the winter in 2006, unusually high honey bee colony losses were reported by bee keepers in the United States and in other countries over the last decade. This syndrome is what is now known as Colony Collapse Disorder. In addition to issues with honey bees, attention to bumble bees and other bees has raised concerns in declines in the number of species and abundance of these pollinators. What is causing the problem? In recent reviews of the data, scientists have identified the interaction of multiple primary factors that affect honey bee health that include parasites (Varroa mites), pathogens (fungi, viruses), nutrition, and colony maintenance. To a lesser extent, pesticides may interact with the above factors resulting in sublethal effects that may affect colony health. Data suggest that pesticides in general, and neonicotinoids in particular, are not primary factors in colony collapse disorder. For bumble bees, data suggest that pesticides may play a role, but there is still a need for more field level studies. There are many issues associated with the interpretation of the data from research studies. For example, laboratory studies tend to evaluate levels of pesticides that are greater than bees are likely exposed to under field conditions. These methods bring into question the accuracy of inferences from lab to field situations. Because of the variable results from different lab and field studies, interpretation can be quite variable. What about neonicotinoid insecticides? Some groups have focused on the class of insecticides called neonicotinoids, citing them as a major cause of the problem with bee health. Regulations restricting the use of neonicotinoid insecticides in Europe have been implemented and are under discussion in Canada. In the U.S., the EPA has accelerated reviews of neonicotinoid insecticides and mandated the addition of a bee advisory box on all products containing neonicotinoids. There is pressure from various groups to remove or further restrict the use of neonicotinoids, especially from ornamental and turfgrass systems. What are neonicotinoid insecticides and their potential risks? Neonicotinoid insecticides are insect neurotoxicants. In the green industries these include imidacloprid, thiamethoxam, clothianidan, acetamiprid, and dinotefuran. They have many desirable features such as broad-spectrum activity, low application rates, low mammalian toxicity, systemic movement upward in plants, and multiple application methods (soil drenches, foliar sprays, or plant injections). They have proved very effective and generally safe in controlling many sucking, plant boring, and turf feeding insects. Their distribution throughout the plant and long residual activity has contributed to their effectiveness in controlling plant damaging insects. Because of these benefits neonicotinoids are widely used in the green industries for managing many potential pest insects. Neonicotinoids are especially useful for tree conservation and invasive insect species management. Bees are being reported to feed on pollen from a wide range of sources which increases their exposure to any chemical found in plant pollen. Statements have been made that higher rates of neonicotinoids are applied in ornamental systems and that this situation increases risks to pollinators. A concern is when neonicotinoids are sprayed on open flowers of insect pollinated plants that with some plant species they 79

89 have the potential to move systemically into pollen, nectar, and guttation fluids, posing particular concern for exposure to pollinators. There is still much we do not know about the effects of pesticides, including neonicotinoids, on pollinators and other beneficial insects, and their movement into and residual activity in various plant parts. What course of action and factors should be considered when managing potential pests in greenhouse and nursery systems? Neonicotinoid insecticides are in the spotlight as a major factor affecting bee health, regardless of what the data suggests. In addition, complete information is still lacking on their impacts on pollinators. The green industries often use products that contain neonicotinoids for managing a wide array of pests. In some situations these materials are the best or only choices; for other pests there are alternatives management tactics that could be used (see list of alternative pesticides at the end of this article). There is the potential for EPA to remove or greatly restrict the use of neonicotinoid insecticides, especially use in ornamental and turf systems. Therefore, it would be wise to reduce the use of and reliance on neonicotinoid insecticides and to be sure you and your employees are aware of risks of the insecticides they are applying to pollinators and non-targets in general. Many other insecticides are also toxic to pollinators and non-targets. Be sure to READ THE LABEL thoroughly and follow the directions. Consider the following when making plant and pest management decisions. Choose non-chemical management tactics whenever possible. Select pesticides that have low impact and are low risk to pollinators. Only use neonicotinoids when other effective products do not exist (ex. reduce reliance on neonicotinoids). Avoid prophylactic use of neonicotinoids (i.e. do not make applications unless you actually have an insect population at levels likely to cause damage to the plant. Do not apply foliar sprays to insect pollinated plants until after petal drop. Similarly, try to avoid trunk and soil injections of neonicotinoids on insect pollinated plants (not enough is known on residual levels of neonicotinoids in the nectar and pollen over time). 80

90 Table 10.1 Alternatives to Neonicotinoids Brand name Chemcial name Labelled for Notes on bees Abamectin SPC 0.15 (In shadehouses, greenhouse, field grown ornamentals, foliage plants, Christmas trees, and other woody plants) Abamectin Control of leafminers and mites. Suppression of aphids, whiteflies and thrips This product is highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area. Aza-Direct (Greenhouses, shadecloths, and nurseries) Azatin XL (Indoor and outdoor use on ornamentals, turf, and horticultural crops) Conserve SC (Landscapes, nurseries, greenhouses, turfgrass) Floramite (greenhouses, shadehouses, landscapes, nurseries, interiorscapes) Fulcrum (ornamentals, flowering and foliage plants, ground covers) Grandevo/Grandevo PTO (field and greenhouse use) Azadirachtin Azadirachtin Spinosad Bifenazate Pyriproxyfen Chromobacterium subtsugae Aphids, beetles, borers, true bugs, caterpillars, flies, leafhoppers, leafminers, mealybugs, mites, psyllids, scales, thrips, weevils, whiteflies Aphids, armyworms, black vine weevil, bagworm, cutworm, cankerworm, leafhoppers, leafminers, sawflies, tent caterpillars, western flower thrips, whiteflies Chrysomelid leaf feeding beetles, European grapevine moth, Nantucket pine tip moth, lepidopterous and sawfly larvae, thrips, shore fly, dipterous gall midges, dipterous leafminers, emerald ash borer, lewis and spider mites Mites (twospotted mite, pacific, strawberry, European red, citrus red, clover mite, southern red, spruce spider, bamboo spider, and Lewis) Aphids, fungus gnats, shoreflies, several scale species, mealybugs, and whiteflies Herbs and spices: armyworms, loopers, saltmarsh caterpillar, aphids, mites, thrips, whiteflies Bee info not noted on label. Bee info not noted on label. Product is toxic to bees when exposed during the 3 hours following treatment. Do not apply to blooming, pollenshedding or nectar-producing parts of plants if bees may forage on the plants during this time period. This product is toxic to bees exposed to direct treatment. Do not apply this product while bees are actively visiting the treatment area. Bee info not noted on label. Product temporarily repels honey bees for up to 4 to 6 days after spraying. Time applications so that pollination is not disrupted. 81

91 Table 10.1 Alternatives to Neonicotinoids (continued) Brand name Chemcial name Labelled for Notes on bees Kontos (greenhouses, nurseries, interiorscape) Spirotetramat Mainspring (greenhouses and nurseries) Pedestal (container and field grown ornamentals in greenhouses, shadehouses, and nurseries) Pylon (ornamental crops and fruiting vegetable crops grown in commercial greenhouses) Shuttle O (commercial greenhouse and shadehouse on ornamental, floral, foliage and ornamental nursery crops) Cyanoaniliprole Novaluron Chlorfenapyr Acequinocyl Adelgids, aphids, leafhoppers, mealybugs, psyllids, rust mites, scale (crawlers), spider mites, spittlebugs, tarsonemid mites, thrips (immature), whiteflies Thrips, aphids, whiteflies, scale Thrips, whiteflies, armyworms, leafminers (suppression only) Spider mites including twospotted spider mite, broad mite, citrus budmite, cyclamen mite, rust mite, caterpillars including beet armyworm, cabbage looper, soybean looper, foliar nematodes, thrips including chilli thirps, and western flower thrips. Citrus red mite, European red mite, Pacific spider mite, spruce spider mite, twospotted spider mite, Willamette spider mite, strawberry spider mite, Texas citrus mite Product is potentially toxic to honey bee larvae through residues in pollen and nectar, but not to adult honey bees. Exposure of adult bees to direct treatment or residues on blooming crops can lead to effects on honey bee larvae. See the Directions for Use section on label for specific crop application instructions that minimize risk to honey bee larvae. Bee info not noted on label. Bee info not noted on label. This product is toxic to bees exposed to direct treatment on bloom crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees are visiting the treatment area. Bee info not noted on label. 82

92 Chapter 11 Insecticides Registered for Greenhouse Ornamentals Stanton A. Gill, Extension Specialist The following tables ( ) list insecticides currently labeled for the most commonly found insect pests of greenhouses. The trade names are those most readily available for use on commercial ornamental plants in Maryland. (Note: This list may not include all brands sold, nor does it imply any preference). Formulation Key: WSP - Water soluble packets; G - Granule; WP - Wettable powder; SG - Soluble granular; EC/ES - Emulsifiable concentrate/suspension; F - Flowable; WDP - Water dispersible granular NC = not classified The following are restricted use insecticides listed in the tables in Chapter 11. Bifenthrin Menace GC 7.9% Flowable (F) Talstar Select Talstar P Up-Star SC Wisdom F Chlorpyrifos DuraGuard ME Chlorpyrifos + Cyfluthrin Duraplex TR Emamectin benzoate Enfold Fenazaquin Magus Fenbutatin-oxide ProMITE 50 WP Flonicamid Aria WSP Imidacloprid AmTide Imidacloprid 2F T&O Bounty Discus Tablets Imidacloprid 2F Select Lada 2F Lada 75 WSP???? Mallet 2F T&O Mallet 75 WSP Mantra 1 G Mantra 2 F Mantra 60 WSP Marathon 1% G Marathon II (F) Lambda-cyhalothrin Scimitar GC Methiocarb Mesurol 75 WP Permethrin Astro Permethrin 3.2 AG Pyrethrins and Piperonyl butoxide (PBO) Pyrethrum TR Pyronyl Crop Spray (Prentox) Pyrenone Crop Spray Pyrethr-It Forumula 2 (Prescription Treatment Brand) Thiamethoxam Flagship 25 WG Flagshiop 0.22 G DISCLAIMER The USER is always responsible for the effects of pesticide residues, as well as for problems that could arise from drift or movement of the pesticides to the property of others. Use pesticides only according to the directions on the label. Follow all directions, precautions, and restrictions. Do not use pesticides on plants or sites that are not listed on the label. Pesticide rates in this publication are recommended only if they are registered with the Environmental Protection Agency and your state department of agriculture. If a registration is changed or cancelled, any rates listed here are no longer recommended. Trade names are used only to give specific information. This publication does not endorse or guarantee any product and does not recommend one product instead of another that might be similar. 83

93 Aphid Control Identification and damage: Aphids are generally small (1 3 mm), soft-bodied insects that may or may not have wings. More than 20 aphid species can infest a range of greenhouse crops. Aphids have the ability to reproduce without mating or egg production, causing populations to increase almost explosively in greenhouses year-round. Monitoring: Aphid control is much more successful when an infestation is detected and controlled early in a crop cycle. Certain plants (salvia, petunias, and pepper transplants) tend to have recurring aphid problems. Many aphid species prefer to feed on the undersides of foliage so make sure the foliage is flipped over and inspected carefully. Ants are also often found feeding on the honeydew of aphids; so if large populations of ants are detected, check closely for the presence of aphids. Winged forms of aphids can be monitored using sticky cards. Winged forms are produced in a greenhouse when the population has reached high levels on individual plants and the aphids are dispersing to establish new colonies on other plants. Place 1 to 2 yellow sticky cards per 1,000 square feet of growing area. Examine the yellow sticky cards at least once per week and replace them after a count is taken. Treatment: Make sure that weeds are controlled under benches and in surrounding areas. Using microscreening on intake vents helps prevent winged aphids from flying into the greenhouse. Aphids can be carried into greenhouses on clothing, infested cuttings, or plugs. Carefully examine plants such as salvia and verbena, known to be preferred by aphids, before moving the plants into a clean greenhouse. Aphids have many naturally occurring predators and parasites, including lady beetles, lacewings, and Aphelinidae wasps, just to name a few. Growers releasing beneficial organisms should only use pesticides listed as having minimal impact on beneficials. Aphids in the upper foliage canopy are easiest to contact with foliar sprays. Systemic insecticides will be most effective against those feeding on new growth. Aphids on older growth -- lower in the canopy -- are the most difficult to kill chemically and may be responsible for producing new aphids that reinfest the upper canopy. Remember to rotate aphid insecticides, as resistance is common. 84

94 Table 11.1 Insecticides for Aphid Control Chemical Name IRAC Code Class Trade Name (Formulation) Abamectin 6 Avermectin Abamectin SPC 0.15 EC Ardent 0.15 EC Avid 0.15 EC Lucid 2F Merlin (Phoenix Merlin) Minx Quali-Pro 85 Re-entry Comments Interval (hours) 12 Foliar spray. Translaminar properties for suppression only. Do not apply through irrigation system. Caution on roses, gerberas, and chrysanthemums. Not recommended for ferns or shasta daisies. Do not get in eyes, on skin, or on clothing. Avoid breathing spray mist. Acephate 1B Organophosphate 1300 Orthene TR 24 Total release cans. Best to apply in early evening when foliage is dry and greenhouse temperatures are between 60 and 80 F. Ventilate greenhouse before reentry. Acephate 90 Contact insecticide. Do not apply to poinsettias after bract formation or to roses and chrysanthemums in flower. See labelphytotoxicity precautions. Acephate 97 UP Systemic with ingestion action. Greenhouse label for anthurium, cacti, carnations, orchids, roses, chrysanthemums, foliage plants, and poinsettias. Do not apply through irrigation system. Do not treat freshly rooted cuttings, poinsettias after bract formation, or roses or chrysanthemums in flower. Toxic to bees and birds. Orthene TT&O (Tree, Turf and Ornamental WP) Systemic. Limited cropssee label. Not for cut flowers. Do not apply to freshly rooted cuttings, poinsettias after bract formation, roses or chrysanthemum in flower.

95 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 86 Re-entry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 30 SG 12 Contact material; translaminar activity. Surfactant may improve efficacy. Do not overhead irrigate for 6 hrs after application. Treat no more than 4 times/year and no more than once every 7 days. TriStar 8.5 SL Water-soluble bags - apply as foliar spray. No more than 5 applications per year. Do not treat more than once every 7 days. Toxic to bees. Azadirachtin NC Botanical Aza-Direct (EC) 4 IGR. By contact or AzaGuard AzaMax AzaSol Azatin O Ecozin Plus 1.2% ME Azatin XL Azatrol Bayer/Bonide neem oil concentrate Molt-X Neemix 4.5 (EC) (= Superneem 4.5 B) ingestion as a repellent, antifeedant, and interference with molting process. May repel adults. Breaks down in spray solution if ph >7.0 and/or not used within 8 hrs. See above. High percent active ingredient and water solubility. See Aza-Direct. Ecozin Plus is only for herbs and vegetables. See Aza-Direct. Apply to moderately moist soils. See Aza-Direct. May reduce waxy bloom on plants. See Aza-Direct. Immatures. Direct spray on pest and longer duration of leaf wetting increases efficacy. Do not treat stressed plants or before root establishment. Ornazin 3% EC 12 See Aza-Direct.

96 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Azadirachtin + Pyrethrins Beauveria bassiana GHA Strain Bifenazate Abamectin NC 3A NC UN 6 Class Botanical Pyrethroid Entomopathogenic fungus Trade Name (Formulation) 87 Re-entry Interval (hours) Comments Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Interferes with the molting process and as an adulticide. Effective on all insect life stages. Do not apply directly to or near water, storm drains or drainage ditches. Do not apply >1 time/ day. Or >10 times per season. Botanigard 22 WP 4 Insect-specific fungus. BotaniGard ES Do not tank mix with Mycotrol O (WP) fungicides. Acts by contact; thorough coverage is essential. Needs relative humidity greater than 70% and F for 8-10 hours. Normally takes 3-7 days for insects to die and 7-10 days after first spray to see a reduction in an insect population. Do not tank mix with fungicides. Product may be used as a pre-plant dip for cuttings. For soil applications do not apply to watersaturated soils. See label for plant list, rates, and specific instructions. Do not treat poinsettias in bract. Note: Formulated for application without additional wetting agents and spreaders. Sirocco (=Prevamite-O) 12 For aphid suppression only. Thorough coverage of foliage is essential; young immatures must be contacted by the spray. Do not make >2 applications per crop per year.

97 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 88 Re-entry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. For best results apply when foliage is dry and temperature is between F. Do not reapply within 48 hrs of application. Ventilate greenhouse before reentry. Menace GC 7.9% Flowable (F) Talstar P (Professional) (F) Talstar Select Up-Star SC (F) Wisdom F Contact insecticide. Thorough coverage is important. Do not apply through any irrigation system. Do not allow runoff to occur. Thorough coverage is important. Foliar application. Do not apply through any type of irrigation system. May not be effective against some aphid populations due to resistance. Thorough coverage is important. Do not apply through any irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can tank mix with plant growth regulators. May not be effective against some aphid populations due to resistance. Thorough coverage is important. Can use for larvae in potting substrate of container plants - see label for preventative and curative treatments. May not be effective against some aphid populations due to resistance Do not apply through irrigation system.

98 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Chlorpyrifos 1B Organophospate DuraGuard ME 24 Microencapsulated formulation. Can be applied as a foliar spray and as a coarse spray to substrate surface. Caution on azaleas, poinsettias, camellias, roses, and variegated ivies. Do not use on kalanchoes. Direct treatment to some open blooms may cause petal drop. See label for plant list, specific rates, and instructions. Chlorpyrifos and Cyfluthrin Chromobacterium subtsugae strain PRAA4-1 (Achromocil) 1B 3A Organophosphate Pyrethroid Duraplex TR (=Descriptor Total Release Insecticide) 24 For wholesalers only. Micro Total Release spray; contact action. Apply when foliage is dry during early evening when temperature is between F. Do not apply through any type of irrigation system. Do not apply under conditions of extreme heat or drought stress. Available in 2 oz container that treats up to 3,000 ft 2. UN Biological Grandevo 4 Contact biological insecticide for young immature stages of foliar feeding insects and mites. May also reduce adult egg laying. Apply to non-blooming plants. Proper application timing to target newly hatched larvae is important. Good spray coverage is important; no systemic activity. Carefully follow label directions. See label about tank mixing. 89

99 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 90 Re-entry Interval (hours) Comments Clothianidan 4A Arena 50 WDG 12 Systemic; must translocate from roots over 1-2 weeks. Thorough coverage is required. Apply to established plants; do not apply treatments <10 days apart. Do not apply to plants in flower wait until all flower petals have fallen off. Do not use a foliar application following a soil application. Only apply to moist soil substrate, not dry or saturated soil. Do not apply during bloom/when bees are foraging. Cyanoaniliprole 28 Diamide Mainspring 4 Contact and systemic activity. Foliar or soil application. Do not apply this product or allow it to drift to plants/weeds in bloom if bees are foraging. Cyfluthrin 3A Pyrethroid Decathlon 20WP 12 Contact. Do not apply through any irrigation system. Spray plants in bloom at times when pollinating insects are not present, such as early morning or late evening. Dichlorvos 1B Organophosphate DDVP 20% * Spray until runoff. Only for greenhouse ornamentals, tomatoes and cucumbers Do not apply when foliage or blossoms are wet as injury may result. Caution on Shasta and Pink Champagne Chrysanthemums and some snapdragons. *Thoroughly ventilate before reentering.

100 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Dinotefuran 4A Neonicotinoid Safari 2 12 Contact and systemic insecticide. Foliar application provides suppression or regulation only. Do not apply until after target plants are through blooming and pollen and nectar are no longer present. No more than 2 foliar or broadcast applications and/or 1 soil application may be made per crop per year. Only apply soil drench to moist soil substrate. Do not apply to dry or saturated substrate. Do not apply foliar sprays to plants that have received a soil drench. Toxic to bees. Fenoxycarb 7B Fenoxycarb Preclude TR 12 IGR; micro encapsulated release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days. Flonicamid 9C Flonicamid Aria (WSP) 12 Water-soluble packets. Insects stop feeding quickly but may remain on plants for up to 5 days. Product has residual control. Do not apply this product more than 2 times consecutively before rotating. Certain pansy cultivars have exhibited sensitivity to product. 91

101 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Horticultural Oil NC Oil Bonide All Seasons Horticultural Spray Oil (Mineral/ paraffinic oil) Golden Pest Spray oil (soybean oil) Lesco Horticultural Oil # Monterrey Horticultural Oil (mineral oil) Pure Spray Green (Mineral oil) Saf-T-Side Spray Oil (Petroleum Oil) Suffoil-X (Petroleum Oil) Summit Year Round Spray Oil (Mineral Oil) SunSpray Ultra Fine Oil TriTek (Mineral Oil) Ultra-Pure Oil (Mineral Oil) Re-entry Comments Interval (hours) 4 Contact insecticide so thorough coverage is very important. Use enough spray solution to completely penetrate the leaf canopy and cover both top and bottom of all of the leaves and stems until wet but without significant runoff. Be cautious on open blooms. Foliar injury may occur if applied during hot, humid conditions. Do not tank mix with more than 1 pesticide. Do not apply through irrigation systems. Do not spray more than 1 time per week. Do not spray when there is an obvious moisture deficit in leaves or the plant is under stress. Test for phytotoxicity for each plant variety before treating. Do not exceed four applications per growing season. Do not use in combination or immediately before/after spraying fungicides or any product containing sulfur. Do not use with carbaryl (Sevin) or dimethoate (Cygon). See label for information on specific plants labeled to treat and phytotoxicity safety. 92

102 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2 F T&O Bounty Discus Tablets Imidacloprid 2F Select Lada 2F Lada 75 WSP Re-entry Comments Interval (hours) 12 Foliar and growing medium applications. Protection period is reduced if media has >30 50% bark content. Systemic. Do not apply product to water logged or saturated substrate. Do not apply as a foliar treatment following a soil application of other imidacloprid products.see label for rates/restrictions based upon container size and application type. See above. Can be used in ebb & flood systems. Tablets are formulated to provide consistent delivery of active ingredient over time. Need adequate substrate moisture for release of active ingredient. Do not apply through any irrigation system. Do not foliar apply following a soil application in the same crop. For greenhouse herbs only (7 day PHI). Systemic. Can incorporate into the substrate before planting. Do not apply while bees are foraging. Do not apply to flowering plants. Apply only after all petals have fallen off. Caution on ferns, Crassula, petunias, and lantana. 93

103 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Imidacloprid Cyfluthrin Class Trade Name (Formulation) Re-entry Interval (hours) Comments 4A Neonicotinoid Mallet 2F 12 Not to be used more than once every 16 weeks. Mallet 75 WSP Soil treatment only. Do not make more than 5 applications per year. See label for rates and restrictions based upon container size, frequency, and application type. Mantra 1G For crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. Mantra 2F Do not apply through any irrigation system. Can be used in ebb+flood systems. Mantra 60 WSP Can be used in ebb+flood systems. Marathon 1% G Apply when root systems are well established. See label for complete plant list, rates, and specific instructions. Marathon II (F) Can apply before egglaying activity of target pests. 4A Discus NG 12 Contact and systemic 3 insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50% bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Apply to flowering plants when pollinating insects are not present. 94

104 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Insecticidal soap NC Potassium salts of fatty acids Insecticidal Soap with Pyrethrins and Neem Oil Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Trade Name (Formulation) Bayer Insecticidal Soap Bonide Insecticidal Soap DES-X Earth-Tone Insecticidal Soap M-Pede Natural Guard Insecticidal Soap Safer Insecticidal Soap Safer End All Insect Killer 95 Re-entry Comments Interval (hours) 12 Complete coverage is essential. Do not apply to tender new foliage. Thoroughly wet infested plant surfaces. Do not spray when plants are under stress. Do not use on new transplants or unrooted cuttings. Do not spray with full sun or when temperature exceeds 90 F. Do not spray blooms or partially open flower buds. Do not use on bleeding heart, gardenia, jade, lantana, lilies, nasturtium, delicate ferns or sweetpea. Use with care on begonia, Euphorbia, fuchsia, geranium, palm, impatiens, ornamental ivy, or succulents. Do not treat poinsettia after bracts start to show color. Test chrysanthemums for varietal sensitivity. Contact insecticide. Do not spray blooms or partially open flower buds. Do not treat crown of thorns, jade, bleeding heart, gardenia, or delicate ferns. Test for varietal sensitivity on begonia, fuschia and impatiens. NC Biological NoFly WP Preferal 12 For non-food crops. Works best between F humidity >80%. Takes about 3-7 days for insects to die. May cause moderate eye irritation. Do not mix with fungicides. See label on storage and application.

105 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Kinoprene 7A Juvenile hormone analogues Lambdacyhalothrin Trade Name (Formulation) 96 Re-entry Interval (hours) Comments Enstar AQ 4 IGR. See label for application information. Thorough coverage is necessary. 3A Pyrethroid Scimitar GC (EC) 24 A spreader-sticker is recommended. Do not apply through any irrigation system. Do not mix with EC formulations or oils. Methiocarb 1A Carbamate Mesurol 75WP 24 Do not apply with foliar fertilizers or oils. Contact insecticide. Effectiveness may be reduced when the spray solution has a ph >7. Do not make more than 2 applications per year per crop; apply at least 10 days apart. Neem oil (clarified hydrophobic extract of Neem oil) OIL of rosemary + peppermint NC Oil Triact 70 4 Apply before insects 70% Need Oil or eggs are present in large numbers. Do not exceed 1.0% rate in the greenhouse. Do not apply to wilted or otherwise stressed plants, or to newly transplanted plants before root establishment. Not suggested for use on cut roses. Do not spray on impatiens flowers. Reapply every 7-21 days until pest pressure is over. Caution if applying to hibiscus flowers. Product is also a fungicide. NC Botanical Ecotec 4 Contact insecticide; labeled for herbs, vegetables; woodies. Use an adjuvant. Thorough coverage is important. Repeat application every 5-7 days. Do not use if temperatures are >90 F.

106 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Permethrin 3A Pyrethroid Astro 12 Contact insecticide. Permethrin 3.2 Ag Thorough coverage of all plant parts is important. Direct application to blooms may cause browning of petals. Marginal leaf burn may occur on salvia, dieffenbachia, and Pteris fern. See label for specifics. Pymetrozine 9B Pyridine Endeavor (WDG) 12 Systemic and translaminar activity. Aphids stop feeding within hours but remain on plant for 2-4 days. Product has some residual activity and will control pests that move onto treated plants. Do not apply to poinsettias in bract. Some restrictions regarding application amounts apply. Pyrethrins 3A Pyrethrin Pyganic Crop Protection 5.0 EC Pyganic EC Herbs are listed on the label. Buffer final spray mix to a ph of In the greenhouse, do not exceed maximum application rate of 1.18 fl. oz./1,000 ft 2. Do not apply more than 1 time per day. See label for rates and applications. 97

107 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Pyrethrins and Piperonyl butoxide (PBO) Class Trade Name (Formulation) 3A Pyrethrin Pyrenone Crop Spray Re-entry Comments Interval (hours) 12 Botanical insecticide plus a synergist to flush insects out of hiding and into contact with spray residues. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can tank mix with other insecticides. Pyronyl Crop Spray No more than 10 applications/season in greenhouse. Can also Pyreth-It Formula 2 (Prescription Treatment Brand) combine with other insecticides for a quicker and more complete kill where insect resistance may a problem. See label for specific instructions. Pyrethrum TR Micro total release aerosol formulation; treats up to 3,000 ft 2. See label for specific instructions. Pyrifluquinazon UN Rycar 12 Contact and translaminar insecticide. Causes immediate stop-feed. Thorough spray coverage needed. Do not apply through any irrigation system. Do not harvest cut flowers for 48 hrs after spraying. Do not compost any treated plant material. For non-food crops only; Do not allow pesticide spray solution to run off outside of the application area. Do not make more than 2 applications per crop cycle. 98

108 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 99 Re-entry Interval (hours) Comments Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for suppression of eggs, nymphs/larvae and pupae. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettia after bract formation; see label for more. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. See label for complete plant list, rates, and specific instructions. Sulfoxaflor (Isoclast R ) + Spinetorum 4C + 5 Sulfoximine XXPire WG 12 Not a neonicotinoid. Has systemic and translaminar activity. Provides knockdown and up to one month of residual control. Do not apply to edible crops. Do not make more than 2 consecutive applications. Do not make more than 4 applications per year. Spirotetramat 23 Sulfoximine Kontos 12# Contact, stomach poison, systemic and translaminar insecticide for both knockdown and residual control. Not a neonicotinoid. Provides knockdown and up to one month of residual control. Do not apply to edible crops or geranium. Start treatments prior to establishment of high pest populations and reapply on an as-needed basis. See label for list of plants, application types, and important plant safety information. #See label for drench REI.

109 Table 11.1 Insecticides for Aphid Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 100 Re-entry Interval (hours) Comments Tau-fluvalinate 3A Pyrethroid Mavrik Aquaflow 12 Spray water should be buffered to ph 5-7. Do not apply more than 4 sprays per month. May work slowly on some species. Allow 3 4 days to evaluate performance. Effectiveness against green peach aphid may vary because of resistance. Caution on roses and poinsettias. Can also use as a dip for flower and foliage cuttings. May cause respiratory allergic response. Thiamethoxam 4A Neonicotinoid Flagship 0.22G 12 Systemic - allow a Flagship 25WDG minimum of one week for smaller plants to translocate to feeding sites of target pest. If leaching, allow at least 7 days for maximum uptake. Flagshipo 25 WDG Apply to foliage or substrate. Product applied to foliage is rapidly absorbed/distributed for rapid control of foliar feeding insects. Product applied to soil will kill soil pests upon contact or ingestion; will also be readily taken up by plant roots to pest feeding sites. Tolfenpyrad 21A METI insecticides Hachi-Hachi 12 Contact insecticide. Phytotoxic to blooms and some plants. See label for rates for cut flowers. Allow at least 10 days between applications. Do not apply to gypsophila, impatiens, salvia, or poinsettia in bract. For use on non-food crops.

110 Caterpillar Control Identification and damage: Caterpillars are the immature forms (larvae) of Lepidoptera (moths and butterflies) pests. This group includes armyworms, cutworms, leaftiers, leafrollers, loopers and sawfly larvae. These insects are only damaging in the immature larval stage; the adults either do not feed or feed only on nectar. Feeding damage includes small holes to totally consumed plant foliage (including defoliation of stems and flowers). This causes either the total loss of plants, or tattered, totally unsalable plants. Adult moths can be attracted to the greenhouse by lights and fly in from the outdoors to lay their eggs (e.g. cabbage loopers). Some caterpillars prefer to hide in the soil during daylight and emerge to feed only at night; others remain on the plants at all times; and still others fold leaves around themselves for protection. It is necessary to identify the pests properly before beginning a control program. Monitoring: Examine foliage for presence of caterpillars. Examine the base of the plant for frass (caterpillar excrement). Look for early damage symptoms. Treatment: Spray when caterpillars are small for the most effective control. This is very important, especially when using biological and botanical controls, e.g. Bacillus thuringiensis, azadirachtin, Beauveria bassiana, and Saccharopolyspora spinosa. The larger the caterpillar, the more damage occurs and the harder it is to control. Timing is therefore very important. 101

111 Table 11.2 Insecticides for Caterpillar Control Chemical Name IRAC Code Class Trade Name (Formulation) Acephate 1B Organophosphate Orthene TT&O 97 (Turf, tree, and Ornamental) WP Re-entry Comments Interval (hours) 24 Systemic. Not for residential greenhouse use. Do not apply to freshly rooted cuttings. For use on limited kinds of crops - see label. Not for cut flowers. Do not apply with a low pressure hand wand. Do not apply to poinsettias after bract formation, roses or chrysanthemum in flower. See label for complete/ limited plant list, rates, and specific instructions Orthene TR Labeled for cabbage loopers, cankerworms and leafrollers. Total release cans. Best to apply in early evening when foliage is dry. Greenhouse temperatures should be between 60 and 80 F for best results. Greenhouse should be ventilated before reentry. See label for specific instructions and phototoxicity concerns on specific plants. Caution using on roses or chrysanthemums in flower or poinsettias in bract. Acephate 90 Labeled for cabbage loopers, cankerworms and leafrollers. Contact insecticide Do not apply to poinsettias after bract formation or to roses and chrysanthemums with open blooms. See label for specific plant phytotoxicity precautions. 102

112 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 103 Re-entry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 70 WSP 12 Do not make more than 5 TriStar 8.5 SL applications/year or more than once every 7 days. Toxic to bees. 70 WSP: Contact insecticide, translaminar activity. Need thorough coverage. Do not irrigate overhead for at least 6 hrs after application. Test for phytotoxicity if using a surfactant. 8.5 SL: Water-soluble bags as a foliar spray. Azadirachtin 18B Botanical Aza-Direct (EC) 4 IGR. By contact or AzaGuard ingestion as a repellent, AzaMax antifeedant, and interference with the Azatin O molting process. May repel adults. Will break Bayer/Bonide neem oil concentrate down in the spray solution if ph>7.0 and/or not used Molt-X within 8 hrs. AzaSol: May be applied AzaSol to any food crop. High percent active ingredient and water solubility; need thorough coverage. Azatin XL: Apply to Azatin XL (EC) moderately moist soils. Azatrol: May reduce the Azatrol waxy bloom on certain ornamental plants. Ecozin Plus: Only for herbs and vegetables in Ecozin Plus 1.2% greenhouse. ME Neemix 4.5: Kills only immature stages. Direct Neemix 4.5 (EC) (=Superneem 4.5B) spray onto pest and longer duration of leaf wetness increases effectiveness. Do not apply to wilted/ stressed plants or unrooted newly transplanted plants. Ornazin 3% EC 12 See above.

113 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Azadirachtin + Pyrethrins Bacillus thuringiensis aizawai strain Bacillus thuringiensis kurstaki strain 18B 3A Class Botanical Pyrethrum Trade Name (Formulation) Re-entry Interval (hours) Comments Azera 12 Works by contact or by ingestion. Quick knockdown. OK on herbs. Kills by interfering with molting process and as an adulticide. Effective on all life stages. Do not apply directly to or near water, storm drains or drainage ditches. Do not apply when windy. Do not apply >1 time/ day. Or >10 times per season. See label. 11 B2 Bacterium Agree WG 4 Stomach poison that must Biobit XL be eaten by target insect to XenTari DF be effective. Treat when larvae are young (1st and 2nd instar larvae). Larvae must be actively feeding on treated, exposed plant surfaces. Insect stops feeding and dies from 1 to 5 days later. See label. Highly compatible with biocontrol programs. 11 B2 Bacterium Condor WP 4 Used only to control Cyrmax WDG small, immature Deliver caterpillars (1st and 2nd Dipel Pro DF instar larvae). Must be ingested to be effective, Dipel ES, DF so thorough coverage is Foray essential. Insect stops Javelin feeding and dies 1 to Monterey Bt 5 days later. See label. Highly compatible with biocontrol programs. 104

114 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Beauveria bassiana GHA Strain NC Class Entomopathogenic fungus Trade Name (Formulation) Re-entry Interval (hours) Comments BotaniGard ES 4 Contains spores that BotaniGard 22 WP attach to cuticle of pest, then penetrate to kill. Do not apply through a thermal pulse fogger. Can be used with ultralow volume equipment and chemigation. Can be used as pre-plant dips for cuttings. Do not apply to pointsettias in bract. Begin applications at first sign of pest; may take 7-10 days for control. Do not tank mix with fungicides or apply with insecticides such as Metasystox R, Neemazad or Thiodan EC. Sticking agents, insecticidal soaps or emulsifiable oils may improve control. Mycotrol O (WP Contact insecticide. Active ingredient is an insect-killing fungus. To be effective needs relative humidity >70% and temps F for 8-10 hours Thorough coverage of all plant parts is important. Do not apply through a thermal pulse fogger. Use caution when making applications to open blooms. Do not apply during a temperature inversion. Do not mix more Mycotrol than needed for that day. 105

115 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. For best results apply during early evening when foliage is dry and temperature is between F. Ventilate greenhouse before reentry. Do not reapply product within 48 hrs of a previous application. See label specific instructions. Menace GC 7.9% (F) Talstar P (Professional) Talstar Select Contact insecticide. Thorough coverage is important. Do not apply through any irrigation system. Do not apply in rain. Do not allow runoff or dripping to occur. Do not apply through any type of irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can be tank mixed with plant growth regulators. Thorough coverage is important. Up-Star SC Do not use more than 1 fl. oz. per 1000 ft 2. Foliar application. Do not use through any irrigation system. Wisdom F Thorough coverage is important. Do not apply through any irrigation system. Do not allow the product to enter any drain during or after application. See label for rates and instructions. 106

116 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Chlorfenapyr 13 Pyrrole Pylon 12 Contact; stomach poison with translaminar activity. For ornamentals and fruiting vegetables. Thorough coverage is needed. Do not apply >3 times within a growing cycle. Not ovicidal. Toxic to bees; apply prior to bloom. Phytotoxicity caution on carnations, dianthus, kalanchoes, poinsettias, roses, salvias and zinnias. See label for plant safety, details and application information (including use on plugs). Pylon TR See above. Total release product, available in 2 oz containers that treats up to 3,000 ft 2. Do not compost any discarded plant materials that have been treated with this product. See label for details, directions, and precautions. Chlorpyrifos 1B Organophospate DuraGuard ME 24 Microencapsulated formulation. Can be applied as a foliar spray and as a coarse spray to soil surface. Caution on poinsettias and variegated ivies. Do not use on kalanchoes. Direct treatment to some open blooms may cause petal drop. See label for plant list, specific rates, and instructions. 107

117 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Chlorpyrifos Cyfluthrin Chromobacterium subtsugae strain PRAA4-1 1B 3A Class Organophosphate Pyrethroid Trade Name (Formulation) Duraplex TR (=Descripton Total Release Insecticide) 108 Re-entry Comments Interval (hours) 24 For wholesalers only. Micro Total Release spray; contact action. Apply when foliage is dry during early evening when temperature is between F. Do not apply through any irrigation system. Do not apply under conditions of extreme heat or drought stress. A 2 oz can treats up to 3,000 ft 2. UN Biological Grandevo 4 For greenhouse herbs and vegetables. Contact biological insecticide for young immature stages. Thorough coverage is important. Proper timing targeting newly hatched larvae is important. Good spray coverage is important; no systemic activity. See label warning if tank mixing. Cyfluthrin 3A Pyrethroid Decathlon 20 WP 12 Do not apply through any irrigation system. A spreader-sticker may enhance coverage of hard to wet leaf surfaces. Good coverage is necessary. Diflubenzuron 15 Benzoylureas Adept (WSP) 12 IGR; water soluble bags. Disrupts normal molting processes of larvae. Apply as soil drench or coarse spray to soil surface. For control of certain foliarfeeding insects, apply as foliar spray. Do not apply to poinsettias, hibiscus, or Rieger begonia. Do not apply to pots on capillary mats. Do not reuse treated potting substrate.

118 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Fenoxycarb 7B Fenoxycarb Preclude Prescription Treatment TR Fenpropathrin + Acephate Imidacloprid Cyfluthrin 3A+1 1B 4A 3 Pyrethroid Organophosphate Re-entry Comments Interval (hours) 12 Micro Total Release. Insect growth regulator. A 2 oz container treats up to 3,000 ft 2. Cans must be stored at room temperature (above 65 F) for 24 hours before application. Not for use on any food crops. Tame/Orthene TR 24 Total release aerosol. Mixture of two contact insecticides. One 16 oz container treats up to 3,000 ft 2. Apply during early evening when foliage is dry and temperature is between F. Make one to three applications per week depending on the severity of the infestation. Do not apply product within 48 hrs of a previous application. Discus NG 12 Contact & systemic insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50% bark content. Do not use a neonicotinoid following application. Highly toxic to bees. Treat flowering plants when pollinating insects are not present. 109

119 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Insecticidal soap NC Potassium salts of fatty acids Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Trade Name (Formulation) Bayer Insecticidal Soap Bonide Insecticidal Soap DES-X Earth-Tone Insecticidal Soap M-Pede Natural Guard Insecticidal Soap Safer Insecticidal Soap Re-entry Comments Interval (hours) 12 Contact insecticide so complete coverage is essential. Do not apply to tender new foliage, unrooted cuttings, new transplants, seedlings or plants under stress by hot (>90 F), humid, or drought conditions. Do not spray when full sun. Do not spray blooms or partially open flower buds. Do not use on bleeding heart, gardenias, jade, lantana, lilies, nasturtiums, delicate ferns or sweetpeas. Use with care on begonias, euphorbia, fuchsia, gardenia, geraniums, impatiens, ornamental ivy, palms, or succulents. Do not treat poinsettias after start of bract coloring. Test on chrysanthemums for varietal sensitivity and do not apply to open blooms. Tank mixing may increase effectiveness and retard development of insecticide resistance, but resulting mixture may be more phytotoxic. NC Biological PFR-97 20% WDG 4 For herbs and vegetables only. See label for application method for specific pest and storage. Works best when >80% relative humidity for 8-10 hrs. Causes moderate eye irritation. Do not apply when bees are foraging. 110

120 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Lambdacyhalothrin Methoxyfenozide Class Trade Name (Formulation) 111 Re-entry Interval (hours) Comments 3A Pyrethroid Scimitar GC (EC) 24 Not for food crops. Contact insecticide. Thorough coverage is important. A spreadersticker is recommended. Do not apply through any irrigation system. Do not mix with other EC formulations or oils. 18 IGR Intrepid 2F 4 IGR. Start when larvae are observed/first sign of feeding damage. Uniform coverage is essential. Do not apply more than 32 fl. oz. per acre per year. Do not make more than 4 applications per acre per year. Apply at least 6 hrs before chance of rain. Novaluron 15 Benzoylureas Pedestal 12 IGR. For armyworm larvae, not adults. Do not use more than once within each generation. Do not apply more than 2 times per crop per year. Do not apply to poinsettias. Permethrin 3A Pyrethroid Astro (EC) Permethrin 3.2 Ag Pyrethrin Pyrethrins Pyganic Crop Protection EC 5.0 Pyganic EC Contact insecticide. Thorough coverage is important. Spraying blooms may cause petal browning. Marginal leaf burn may occur on salvia, dieffenbachia, and Pteris fern. 12 Herbs are listed on label. In greenhouse, do not exceed maximum application rate of 1.18 fl. oz./1,000 ft 2. Do not reapply within 3 days except under extreme pest pressure. Do not apply when honey bees are active.

121 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Pyrethrins 3A Pyrethrin Pyronyl Crop Spray (Prentox) Pyrethrins and Piperonyl butoxide (PBO) 3A+2 7A Pyrethrin PBO Pyrenone 5.0 EC Crop Spray Prentox Pyronyl Crop Spray Pyreth-It Formula Re-entry Comments Interval (hours) 12 Can combine with other insecticides for a quicker and more complete kill where insect resistance may be a problem. No more than 10 applications/ season in greenhouse. 12 Botanical insecticide plus synergist to flush insects out of hiding into contact with spray residues. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can tank mix with other insecticides. Can combine with other insecticides for a quicker and more complete kill where resistance may be a problem. Contact insecticide. Can tank mix with insecticides to enhance efficacy and flush insects out of hiding into contact with spray residues. Apply when foliage is dry. Pyrethrum TR Total release aerosol. A 2 oz can treats up to 3,000 ft 2. See label for caterpillar species controlled. Pyridalyl NC Pyridalyl Overture 35WP 12 Controls by contact and ingestion (also has translaminar activity). Do not apply more than 3 times per crop cycle or more than 3 times per 6 months. Can apply by high volume sprayers or low volume application equipment (i.e. PulseFOG or Electrostatic Spraying Systems. Do not apply through irrigation system.

122 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Sulfoxaflor (Isatox R ) + Spinetorum 4c 5 Class Trade Name (Formulation) Re-entry Interval (hours) Comments Sulfoximine XXpire WG 12 Spinetorum (contact and stomach poison) and sulfoxaflor (contact, systemic and translaminar) for knockdown and up to one month of residual control. Not a neonicotinoid. Do not apply to edible crops. See label for specific caterpillars (also sawflies). Spinosad 5 Spinosyn Conserve SC (EC) 4 Contact and stomach poison insecticide. Thorough leaf coverage is important. Not for edible crops. See label for application types, use and rate restrictions. Except for greenhouses and structures that can be altered to be closed or open, do not reapply within less than 7 days. Entrust Contact and stomach poison. Thorough leaf coverage is important. See label for application types, use and rate restrictions. Can apply to herbs and vegetable transplants. Tau-Fluvalinate 3A Pyrethroid Mavrik Aquaflow 12 Contact. May cause respiratory allergic response. Spray water should be buffered to ph 5-7. Do not apply more than 4 sprays per month. May work slowly on some species. Allow 3 4 days to evaluate performance. Caution on roses and poinsettias. Can also be used as a dip for flower and foliage cuttings. 113

123 Table 11.2 Insecticides for Caterpillar Control (continued) Chemical Name IRAC Code Class Tolfenpyrad 21A METIinsecticides Trade Name (Formulation) Re-entry Interval (hours) Comments Hachi-Hachi 12 Contact insecticide for use on early stage insects. Do not use on food crops. Phytotoxic to blooms and some plants. Refer to label for more information. See label for rates for cut flowers. Allow at least 10 days between applications. Apply no more than 2 applications per crop cycle. Do not apply to Gypsophilia, impatiens, salvia, or poinsettias in bract. 114

124 Foliar Nematode Control Identification and damage: Foliar nematodes (Aphelenchoides spp.) are microscopic plant-parasitic nematodes found within leaf tissue. Populations can build up very rapidly in greenhouses where there are no interruptions in their life cycle. Foliar nematodes are most damaging on Ageratum spp.; Anthurium andraeanum; Begonia spp. and hybrids; Coleus spp. and hybrids; Cyclamen persicum (florist s cyclamen); ferns, Ficus spp. (rubber plant); Hibiscus rosa-sinensis; Impatiens spp.; Lilium spp. and hybrids; orchids; Pelargonium x hortorum (florist s geranium); Peperomia spp.; Saintpaulia ionantha (African violet) Salvia spp.; Sinningia x (florist s gloxinia); and Vanda spp. (vanda orchid). Foliar nematode feeding kills leaf tissue and causes browning of foliage and leaf blotches. The main leaf vein acts as a barrier to nematodes within leaf tissue. To reach other leaf sections, foliar nematodes emerge from stomata under moist conditions, and migrate over the leaf surface. The damaged leaf therefore appears with different stages of discoloration from pale green, to yellow, and eventually brown. On plants with parallel veins, the brown blotchy symptoms appear as long stripes; on plants with netted veins, they appear like angular patchwork. At low population densities, no symptoms may be apparent on plants. Once symptoms appear, the nematodes have increased to large population levels. Populations often build over the course of the growing season, with higher levels (and increased damage) in late summer/fall vs. the spring. Monitoring: Look for damage, especially on lower leaves. Closely inspect areas prone to splashing water, particularly from new transplants. Nematodes can survive in dead foliage (that often cling on plant stems) for several months so remove dead foliage promptly. Foliar nematodes are extremely small and cannot be seen unless examined under a dissecting microscope. Suspected leaf tissue can be sent to an Extension specialist or a diagnostic lab for identification. Treatment: Remove infested plants and dead foliage promptly. Soil, containers, and tools should be fumigated or steamed before use. Sanitation of previous crop debris is important. Table 11.3 Nematicides for Foliar Nematode Control Chemical Name IRAC Code Class Trade Name (Formulation) 115 Re-entry Interval (hours) Comments Chlorfenapyr 13 Chlorfenapyr Pylon 12 Contact; stomach poison with translaminar activity. For ornamentals and fruiting vegetables. Thorough coverage is needed. Do not apply >3 times within growing cycle. Not ovicidal. Toxic to bees; apply prior to bloom. Phytotoxicity caution on carnations, dianthus, kalanchoe, poinsettias, roses, salvias and zinnias. See label for plant safety and application details (including use on plugs)..

125 Fungus Gnat Control Identification and damage. Fly species belonging to the closely related Sciaridae and Mycetophilidae families are known as longhorned flies, or fungus-eating gnats. They are slender, long-legged, mosquitolike insects with long antennae. Species of fungus-eating gnats can carry plant pathogenic fungi and feed on roots and stems. Those belonging to the Sciaridae family are commonly called dark-winged fungus gnats because the wings and bodies of most species are gray to black. Those belonging to the Mycetophilidae family are commonly called fungus gnats. Most of these species have clear wings and yellow-brown bodies. The immature maggots of dark-winged fungus gnats are translucent and worm-like in shape, with a black head capsule. Fungal diseases are spread primarily by dark-winged fungus gnats. The diseases can be spread throughout a greenhouse through spores that may be carried from plant to plant as flies migrate through the greenhouse. Fly larvae of some fungus-eating gnat species can also directly damage plants by feeding on root hairs and tunneling into the roots and stems of susceptible plants. Extended periods of cloud cover cause high humidity, which promotes high soil moisture. These conditions are ideal for the development of fly maggots (larvae) in greenhouse growing substrate. For example, crops such as poinsettia are often damaged by fungal root rots and root feeding while under mist during propagation and when growing in containers in overwatered soils. Monitoring. Monitor larvae of fungus gnats by using 1-inch diameter potato disks placed on the surface of the potting substrate. Place disks at the rate of 10 disks per 1,000 square feet of greenhouse production area. The maggots will migrate to the underside of the potato disk where they feed. Pick up and examine the disk 1 to 2 times a week, and record the number of maggots found. The maggot count can be used to determine if treatment is necessary or whether a biological or chemical treatment has been effective in reducing the number of maggots in the substrate. Adult fungus-eating gnats are attracted to yellow sticky cards. Use a hand lens (10x to 15x magnification) for field identification. Sticky cards laid flat on the soil surface capture 50 60% more adult fungus-eating gnats than cards placed vertically. Take the yellow sticky card counts on a weekly basis to determine whether the population is increasing or decreasing. Treatment: Because fungus-eating gnats prefer moist soils, avoid keeping soils wet for extended periods of time. Use of horizontal air flow (HAF) fans improves circulation in the greenhouse and helps keep soil drier. Controlling algae on the bench surface and in the areas under the bench will help reduce the nuisance population of shore flies. Repeat applications of many pesticides are necessary since they do not control fungus gnat eggs or pupae. The biological control product, Gnatrol, is effective only on young larvae, not mature larvae. It should be applied before population levels are high, as should any beneficial insect release. Insect growth regulators are very effective on fungus gnats. 116

126 Table 11.4 Insecticides for Fungus Gnat Control Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Acephate 1B Organophosphate 1300 Orthene TR 24 Adult control only. Total Release cans; available in 6 oz container that treats 2,700-4,500 ft 2. Apply during early evening when foliage is dry. Greenhouse temperatures should be between 60 and 80 F. Ventilate before reentry. See label for complete plant list, rates, and specific instructions. Acetamiprid 4A Neoniconotoid TriStar 8.5 SL 12 For larvae. Water-soluble bags applied as a foliar spray. Thoroughly wet upper inch of growing substrate. Do not make more than 5 applications per year and do not reapply more than once every 7 days. Toxic to bees. TriStar SG For larvae. Contact insecticide with translaminar activity. Thorough coverage is important. Apply as a directed spray to thoroughly wet upper inch of growing substrate. Do not overhead irrigate for 6 hrs after application. Do not make more than 4 applications per year and do not reapply more than once every 7 days. 117

127 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 118 Re-entry Interval (hours) Comments Azadirachtin 18B Botanical Aza-Direct (EC) 4 No adult control. Kills Azatin XL (EC) by ingestion or contact. Ecozin Plus 1.2% May reduce insect ME damage by repelling and Ornazin (EC) 12 deterring feeding of all insect stages. Do not use with Bordeaux mixture, triphenyltin hydroxide, lime sulfur, Rayplex iron or other highly alkaline materials. Use within 8 hrs. Reduce ph if irrigation water ph >7.0. AzaGuard AzaMax See Aza-Direct. Larvae only. Azadirachtin Pyrethrins Bacillus thuringiensis Serotype 14 (=israelensis) Azatin O Azatrol Ecozin Plus 1.2% ME Molt-X Ornazin (EC) 12 See Aza-Direct. May reduce the waxy bloom on certain ornamental plants. Only for herbs and vegetables in greenhouse. See Aza-Direct. See Aza-Direct. Larvae only. 18B 3A Botanical Pyrethroid Azera 4 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Kills by interfering with molting process and as an adulticide. Effective on all insect life stages. Do not apply >1 time/ day or >10 times per season. 11A1 Bacterium Dipel PRO DF 4 Stomach poison - must be Gnatrol Biological ingested to be effective Larvicide (F) so thorough coverage needed. Target small, Gnatrol DG immature caterpillars Biological Larvicide (1st and 2nd instars. Gnatrol WDG Insect stops feeding and dies 1-5 days later. Highly compatible with biocontrol programs.

128 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Contact micro total release insecticide for adults. Apply during early evening when foliage is dry and temperature is between F. Ventilate before reentry. Do not reapply product within 48 hrs of a previous application. Menace GC 7.9% Flowable Talstar P (Professional) (F) Talstar Select (FC) Up-Star SC Wisdom F Contact insecticide. Thorough plant coverage is important. Do not apply through irrigation system. Do not apply to runoff. For adults. Foliar application. Thorough coverage is important. Not for use on food crops. Do not apply through irrigation system. Can use for larval control in container plant potting substrate; foliar treatment for adults. Do not apply through irrigation system. Spreader stickers are not necessary. Not for edible plants. Can tank mix with plant growth regulators. For larvae and adults. Do not apply through irrigation system. Use as a foliar application. Can use as a drench application for larval control. Thorough coverage is important. Do not apply through any irrigation system. Do not allow the product to enter any drain. 119

129 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Chlorfenapyr 13 Pyrrole Pylon 12 Contact; stomach poison with translaminar activity for both larvae and adults. For ornamentals and fruiting vegetables only. Thorough coverage is needed. Do not apply >3 times within a season. Not ovicidal. Toxic to bees; apply prior to bloom. Phytotoxicity caution on carnations, dianthus, kalanchoe, poinsettias, roses, salvias and zinnias. See label for plant safety, details and application information (including use on plugs). Pylon TR See above; for both larvae and adults. Total release product, available in 2 oz containers that treat up to 3,000 ft 2. Do not compost any discarded plant materials that have been treated with this product. See label for details, directions, and precautions. Chlorpyrifos 1B Organophospate DuraGuard ME 24 Microencapsulated formulation. Can be applied as a foliar spray and as a coarse spray to soil surface. Caution on poinsettias and variegated ivies. Do not use on kalanchoes. Direct treatment to some open blooms may cause petal drop. See label for plant list, specific rates, and instructions. 120

130 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Chlorpyrifos Cyfluthrin 1B 3A Class Organophosphate Pyrethroid Trade Name (Formulation) Duraplex TR (=Descriptor Total Release Insecticide) 121 Re-entry Comments Interval (hours) 24 For wholesalers only. Micro Total Release spray; contact action. Apply to dry foliage during early evening when temperature is between F. Do not apply through any irrigation system. Do not apply under conditions of extreme heat or drought stress. Available in 2 oz container that treats up to 3,000 ft 2. Cyfluthrin 3A Pyrethroid Decathlon 20WP 12 Contact for adults. Good coverage is necessary. Do not apply through any irrigation system. Spray plants in bloom when pollinating insects are not present, such as early morning or late evening. Cyromazine 17 Molting disruptor Citation 75 WP 12 IGR. Apply to the substrate for control of larvae. Available in water soluble packets. See label for information on use in low volume systems. Diflubenzuron 15 Benzoylureas Adept (WSP) 12 IGR; water soluble bags. Disrupts normal molting processes of insect larvae. Apply as soil drench or coarse spray to soil surface. It is recommended that breeding areas under benches and other noncrop areas be treated at the same time as crop is treated. Do not apply to poinsettias, hibiscus, or Rieger begonia. Do not apply to pots on capillary mats. Do not reuse treated potting substrate.

131 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Dinotefuran 4A Neonicotinoid Safari 2 G 12 Apply to growing substrate for control of fungus gnat larvae. Only apply soil drench to moist soil substrate. No more than one soil application may be made per crop per year. Do not apply until after target plants are through blooming and pollen and nectar are no longer present. Horticultural Oil NA Oil Bonide All Seasons Horticultural Spray Oil (Mineral/ paraffinic oil) Golden Pest Spray Oil, (soybean oil) MONTEREY Horticultural Oil (Mineral Oil) PureSpray Green, (Mineral Oil) SuffOil-X (Petroleum oil SunSpray Ultra fine oil Summit Year Round Spray Oil (Mineral Oil) TriTek (mineral oil) Ultra-Pure Oil (Mineral Oil) Contact insecticide for adults. Limited plants labeled for greenhouse use. See label for specific plants and phytotoxicity information. Contact insecticide; thorough coverage of all plant parts is important. Foliar injury may occur if applied during hot, humid conditions. Do not tank mix with more than one pesticide. Do not apply through irrigation systems. Be cautious spraying open blooms. Do not spray when there is an obvious moisture deficit in leaves, or when plants are under stress. Do not spray more than once per week. Do not exceed four applications per growing season. Do not use in combination or immediately before/after spraying fungicides or any product containing sulfur. Do not use with carbaryl or dimethoate. 122

132 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2F T&O Bounty Lada 2F Lada 75 WSP Mallet 2F Mallet 75 WSP Re-entry Comments Interval (hours) 12 Systemic for soil larvae control. Protection period is reduced if substrate has >30 50 % bark content. Do not apply product to soils that are waterlogged or saturated. Do not apply while bees are foraging. Do not apply to plants that are flowering (only apply after all flower petals have fallen off). See label for details and rates/restrictions based upon container size and application type.. See above. Drench for larvae only. Do not apply product to soils that are waterlogged or saturated. See label for specific instructions. No adult fungus gnat control. Larvae in the soil will be controlled by drench or incorporation. Can incorporate into the medium before planting. Caution using on ferns, Crassula, petunias, and lantana. See label for application options. For containers only. See label. See AmTide. For larval control; soil applications only. Not to be used more than once every 16 weeks. Soil treatment only for larvae. Do not make more than 5 applications per year. 123

133 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Imidacloprid Cyfluthrin Class Trade Name (Formulation) Re-entry Interval (hours) Comments 4A Neonicotinoid Mantra 1 G 12 For soil incorporation only to control larvae. For crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. See label for application options, rates, and details. Mantra 2F See above Marathon 1G Larvae in the soil controlled by incorporation. See above. Apply when root systems are well established. See label for complete plant list and specific instructions. Marathon II Systemic; larvae aree controlled by drench or incorporation. Applications can be made before egg-laying activity of target pests. See label for application options, rates, and details.. 3A Discus N/G 12 For both adults and larvae. Contact & systemic 4A insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Treat flowering plants when pollinating insects are not present. See label for application types, rates, and details. 124

134 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Class Trade Name (Formulation) Re-entry Interval (hours) Comments NC Biological NoFly WP 12 Foliar application for larvae. Thorough coverage needed. Works best at temperatures between F and high humidity. Avoid breathing spray mist. Causes moderate eye irritation. Takes ~3-7 days for insects to die. See label for storage and application details. Preferal Apply as a drench, soil surface spray, or chemigation for larvae. Frequent scouting is critical to success. Product is most effective when relative humidity >80 % for 8-10 hrs. Kinoprene 7A Juvenile hormone mimic Nematodes, beneficial (= Entomopathogenic) NC Biological NemaShield (Heterorhabditis bacteriophora) Nemasys (S. feltiae) ScanMask (S. feltiae) Enstar AQ 4 IGR; see label for application information. Thorough coverage is necessary. Water as a drench after spraying. Some varieties of roses show delayed damage. 0 Biological control. Controls larval stages. Sensitive to UV light; do not use in direct sun. Works best in substrate at temperatures of F. Substrate should be moist prior to, during, and after application. Remove filters from application equipment. Substrate temperatures should be between ºF for at least 2 weeks after application. Store in refrigerator. See label for complete instructions. 125

135 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Oil (essential) rosemary oil & peppermint oil Class Trade Name (Formulation) 126 Re-entry Interval (hours) Comments NC Ecotec 4 Contact insecticide; labeled for vegetables, herbs; for adult fungus gnats. Use an adjuvant. Thorough coverage is important. Repeat application every 5-7 days. Do not use if temperaturess are >90 F. Permethrin 3 Pyrethroid Astro 12 Use sufficient water to obtain full coverage. May cause petal browning. Do not spray chrysanthemum blooms, salvia, Pteris fern, and Dieffenbachia. Permethrin 3.2 Ag See above. Some rose varieties are sensitive. Pyrethrins 3A Pyrethrin Pyganic Crop Protection 5.0 EC Pyrethrins and Piperonyl butoxide (PBO) 3A Pyrethrin Prentox Pyronyl Crop Spray Pyrenone Crop Spray Pyreth-It Formula 2 (Prescription Treatment Brand) Pyrethrum TR 12 For adults. Herbs are listed on label. Buffer final spray mix to a ph of In the greenhouse, do not exceed maximum rate of 1.18fl. oz./1,000 ft 2. Do not apply more than once per day. 12 Botanical insecticide plus synergist to flush insects out of hiding and into contact with spray residues. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can tank mix with other insecticides. See above. No more than 10 applications/season in greenhouse. For adults. See above. For adults. Micro total release aerosol for greenhouses; container treats up to 3,000 ft 2.

136 Table 11.4 Insecticides for Fungus Gnat Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for control/ suppression of eggs, nymphs/larvae and pupae. Do not use low volume application equipment to control these soilinhabiting insects; apply as a sprench. Also treat under benches or where insects tend to breed when treating plants. Ensure complete coverage, indicated by moist soil surfaces. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettia after bract formation; see label for details. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. See label for complete plant list, rates, and specific instructions. Thiamethoxam 4A Neonicotinoid Flagship 25WG (WDG) 12 Systemic insecticide for control of larvae. Apply to growing substrate. Product applied to soil will kill soil pests upon contact or ingestion; will also be readily taken up by plant roots to pest feeding sites. See label for application directions. 127

137 Leafminer (Larvae) Control Identification and damage: Leafminer flies are tiny (2 mm) flies that resemble small yellow and black fruit flies. Adult flies puncture foliage to feed on plant juices. The punctured spots turn white with time and give leaves a speckled appearance. Eggs are laid on upper leaf surfaces; newly hatched larvae migrate within the leaf where they feed for 4 to 6 days. Larvae destroy leaf cells as they feed, leaving behind winding trails ( mines ). The mines increase in length and width as the insects grow. The appearance of these larval mines reduces the aesthetic value of a plant. Third instar larvae drop to the soil or onto lower leaves to pupate. Monitoring: The best initial defense against leafminers is to refuse to accept infested cuttings into the greenhouse. Incoming plant material should be inspected for leaf stipples and active mines and held for several days to see if mines develop from leaf stipples. Yellow sticky cards can be used to detect adult activity and to monitor population levels. Treatment: High populations may require sprays every 3 to 4 days to kill new adults as they emerge from the soil. Early morning sprays can kill adult females before they lay eggs. Use products with translaminar activity to kill immature larvae within foliage. Remember to rotate insecticides, as resistance is common. If releasing beneficial insects, remember to only use pesticides listed as having minimal impact on natural enemies. 128

138 Table 11.5 Insecticides for Leafminer Control Chemical Name IRAC Code Class Trade Name (Formulation) Abamectin 6 Avermectin Abamectin SPC 0.15 EC Ardent 0.15EC Avid 0.15EC Merlin (Phoenix Merlin) Lucid Minx Acephate 1B Organophosphate 1300 Orthene TR Acephate 90 Acephate 90 Orthene TT&O 97 WP Re-entry Comments Interval (hours) 12 Foliar contact spray with translaminar properties. Thorough coverage of all plant parts is important. Do not apply through any type of irrigation system. Caution on roses, chrysanthemums, and gerbera. Do not use on ferns or Shasta daisies. Do not get in eyes, on skin, or on clothing. Avoid breathing spray mist. See label for details and resistance management. 24 Total release cans. Best to apply in early evening when foliage is dry. Greenhouse temperatures should be between F for best results. Greenhouse should be ventilated before reentry. See label for specific instructions. Contact insecticide. Do not apply to poinsettias after bract formation or to roses and chrysanthemums with open blooms. See label for specific plant phytotoxicity precautions. Systemic. For use on limited kinds of crops - see label. Not for cut flowers. Do not apply with a low pressure hand wand. Do not apply to poinsettias after bract formation, roses or chrysanthemum in flower. Do not apply to freshly rooted cuttings See label for plants, rates, and specific instructions. 129

139 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 70 WSP 12 Do not apply more than TriStar 8.5 SL 4 times per year. Do not reapply more than once every 7 days. Toxic to bees. A surfactant may improve efficacy. TriStar 70 WSP: Contact insecticide with translaminar activity. Thorough coverage is important. Do not overhead irrigate for 6 hrs after application. TriStar 8.5 SL: Watersoluble bags applied as a foliar spray. Azadirachtin 18B Botanical Aza-Direct (EC) 4 IGR. By contact or AzaGuard ingestion as a repellent, antifeedant and AzaMax interference with molting Azatin O process. May repel adults. Molt-X Breaks down if spray solution ph is >7.0 and/or AzaSol not used in 8 hrs. Azatin XL (EC) AzaSol: Can use on any food crop. High percent Azatrol active ingredient and Ecozin Plus 1.2% water solubility. Need ME thorough coverage. Azatin XL: Apply to Neemix 4.5 (EC) moderately moist soils. (=Superneem 4.5 B) Azatrol: May reduce the waxy bloom on certain ornamental plants. Ecozin Plus: Only for herbs and vegetables in greenhouse. Neemix 4.5: Only for immature stages. Direct spray on pest and longer Ornazin 3% EC 12 duration of leaf wetness increases effectiveness. Do not apply to wilted/ stressed plants or unrooted newly transplanted plants. 130

140 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Azadirachtin Pyrethrins 18B 3A Class Botanical Pyrethroid Trade Name (Formulation) Bifenthrin 3A Pyrethroid Menace GC 7.9% (F) Bifenazate Abamectin 6+UN Re-entry Interval (hours) Comments Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Kills by interfering with the molting process and as an adulticide. Effective on all insect life stages. Do not apply >1 time/day or >10 times per season. Talstar Select Wisdom F Sirocco (=Prevamite O) 12 Contact insecticide. Thorough coverage of all plant parts is important. Do not apply through any irrigation system. Do not treat to runoff. Thorough coverage is important. Do not apply through any type of irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can tank mix with plant growth regulators. Do not apply through irrigation system. 12 Thorough coverage of foliage is essential; young immatures must be contacted by the spray. Do not make >2 applications per crop per year. Chlorpyrifos 1B Organophosphate DuraGuard ME 24 Microencapsulated formulation. Can be applied as a foliar spray and as a coarse spray to soil surface. Caution on poinsettias, roses, and variegated ivies. Do not use on kalanchoes. Direct treatment to some open blooms may cause petal drop.

141 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 132 Re-entry Interval (hours) Comments Cyromazine 17 Cyromazine Citation 75 WP 12 IGR for control of fly (Dipterous) leafminer larvae. Not labeled for caterpillar or beetle leafminers. Available in water soluble packets. See label for information on use in low volume systems and mandatory rotation. Make no than 6 applications to one crop. Diflubenzuron 15 Benzoylurea Adept (WSP) 12 IGR; water soluble bags. Disrupts normal molting process of larvae. Apply as soil drench or coarse spray to soil surface. Do not apply to poinsettia, hibiscus, or Rieger begonia. Do not apply to pots on capillary mats. Do not reuse treated substrate. Dinotefuran 4A Neonicotinoid Safari 2 G 12 Contact and systemic insecticide. Foliar application provides suppression or regulation only. Do not apply until after target plants are through blooming and pollen and nectar are no longer present. Make no more than 2 foliar or broadcast applications and/or 1 soil application per crop per year. Only apply soil drench to moist soil substrate. Do not apply foliar sprays to plants that have received a soil drench. Toxic to bees. Fenoxycarb 7B Fenoxycarb Prescription Treatment Brand Preclude TR 12 IGR. Micro encapsulated release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days.

142 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2F T&O Bounty Discus Tablets Imidacloprid 2F Select Lada 2 F Lada 75 WSP Re-entry Comments Interval (hours) 12 Systemic. Protection period is reduced if media has >30 50 % bark content. Protection onset is translocation delayed in woody plants. Do not apply to soils that are waterlogged or saturated Do not apply while bees are foraging. Do not apply to plants that are flowering (only apply after all flower petals have fallen off). See label for details and rates/restrictions based upon container size and application type. Control of larvae only. Tablets are formulated to provide consistent delivery of active ingredient over time. Release of active ingredient is dependent on presence of adequate soil moisture. Follow label directions. For greenhouse herbs only (7 day PHI). See AmTide. Do not apply through any irrigation system. Do not foliar apply following a soil application in the same crop. Suppression only. Systemic. Can incorporate into the substrate before planting. Caution on ferns, Crassula, petunias, and lantana. See label for application options, rates, and details. For containers only. 133

143 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 134 Re-entry Interval (hours) Comments Imidacloprid 4A Neonicotinoid Mallet 75 WSP 12 For control of first generation; make first application as soon as petal-fall is complete. Best control results from earliest possible application. For optimal control of second and succeeding generations, make applications early in adult flight stage against egg and early instar larvae. May need a second application 10 days later if severe pressure continues or if generations are overlapping. A single application may result in suppression only. Will not control late stage larvae. Do not make a foliar application following a soil application in the same crop. Apply no more than 5 times per year. Mantra 1G Only for crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. Mantra 2F Do not make a foliar application of imidacloprid following a soil application to the same crop. Mantra 60 WSP Protection period is reduced if substrate has >30 50 % bark content. See label for use restrictions. Marathon 1% G Apply when root systems are well established. Marathon II Applications can be made before egg-laying activity of target pests.

144 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Imidacloprid Cyfluthrin 4A 3A Class Insecticida Soap NC Potassium salts of fatty acids Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Trade Name (Formulation) 135 Re-entry Interval (hours) Comments Discus N/G 12 Contact & systemic insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Make applications to flowering plants during times when pollinating insects are not present. See label for application types, rates, and details. M-Pede 12 Contact insecticide for control of fly (Dipterous) leafminer larval populations. Short residual activity. Thorough coverage of all plant parts is important. Refer to label for information on plant safety and tank mixing. NC Biological Preferal 12 Foliar or soil application. Not toxic to humans. Works best at temperatures between F with >80 % relative humidity. Typically takes 3-7 days for insects to die. Do not mix with fungicides. See label for storage and application details. Kinoprene 7A Juvenile hormone mimic Enstar AQ 4 IGR; see label for application information. Thorough coverage is necessary. Water as a drench after spraying. Some varieties of roses show delayed damage. See label for specific rates and instructions.

145 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Lambdacyhalothrin Neem oil (clarified hydrophobic extract of Neem oil) Class Trade Name (Formulation) 136 Re-entry Interval (hours) Comments 3A Pyrethroid Scimitar GC 24 Contact adulticide. Thorough coverage is important; a spreadersticker is recommended. Do not apply through any irrigation system. Do not mix with EC formulations or oils. NC Oil Triact 70 4 Apply before insects or eggs are present in large numbers. Do not apply to wilted or stressed plants, or new transplants prior to root establishment. Caution if applying to hibiscus flowers. Not suggested for use on cut roses. Do not spray on impatiens flowers. Do not make more than 5 applications per year and do not reapply more than once every 7 days. Product is also a fungicide. Novaluron 15 Benzoylurea Pedestal 12 IGR. Does not control adults. For suppression only of serpentine and citrus leafminers. Do not use product more than once within each generation cycle. Do not make more than 2 applications per crop per year. Do not apply to poinsettias. Oil of rosemary + peppermint NC Botanical Ecotec 4 Contact insecticide; labeled for herbs, vegetables; woodies. Use an adjuvant. Thorough coverage is important. Repeat application every 5-7 days. Do not use if temperatures are >90 F.

146 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Oil, Horticultural Class Trade Name (Formulation) NC Oil Bonide All Seasons Horticultural Spray Oil (mineral oil) Golden Pest Spray Oil (soybean oil) JMS Stylet Oil# (Paraffinic/mineral oil) Lesco Horticultural Oil (Mineral Oil) Monterey Horticultural Oil (mineral oil) PureSpray Green (petroleum oil) SuffOil-X (paraffinic oil) SunSpray Ultra-fine Spray Oil (paraffinic oil) TriTek (mineral oil) Ultra-Pure Oil (petroleum oil) Re-entry Comments Interval (hours) 4 Complete coverage needed. Horticultural oil sprays applied to new leaf growth may inhibit egg laying, but must be repeated on a weekly basis during each flush cycle. On woody plants, Dormant oil can help deter egg-laying by female moths, but it does not stop adult females from laying eggs on a leaf that did not get the spray. Do not apply if plants are under any stress or during periods of prolonged high temperatures combined with high relative humidity. Avoid spraying in greenhouses under overcast conditions. Do not exceed label rates or apply more often than recommended. Effectiveness at temperatures below 50 F is reduced. Do not use within 2 weeks of sulfur or within 7 days of Captan. Do not apply through any irrigation system. See label for cautions if using with/ before/following application of certain products and for use restrictions and mixing cautions. # Only labeled for mums. poinsettias, dieffenbachia, & philodendron. 137

147 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Permethrin 3A Pyrethroid Astro Permethrin 3.2 Ag 12 Contact insecticide. Thorough coverage of all plant parts is important. Direct application to blooms may cause browning of petals. and marginal leaf burn on salvia, dieffenbachia, and Pteris fern. Perm-Up 3.2EC See above. Mums only. Contact insecticide for leafminer adults on mums only. Avoid spraying chrysanthemum blooms. Pyrethrins 3A Pyronyl Crop Spray (Prentox) 12 For non-food ornamentals (Herbs are listed on the label). Do not apply when honey bees are active. May also be combined with other insecticides for a quicker and more complete kill where insect resistance may be a problem. See label for specific rates and instructions. Pyrethrins and Piperonyl butoxide 3A Pyrethrin Pyrenone 5.0 Crop Spray (EC) Prentox Pyronyl Crop Spray Pyrethrum TR 12 A botanical insecticide plus a synergist to flush insects out of hiding and into contact with spray residues. See label for details. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can tank mix with other insecticides. No more than 10 applications/season in greenhouse. Total release aerosol. Available in 2 oz container that treats up to 3,000 ft

148 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 139 Re-entry Interval (hours) Comments Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for suppression of immature spotted tentiform leafminer only. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettia in bract. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. Spinosad 5 Spinosyn Conserve SC (EC) 4 Contact and stomach poison for fly (Dipterous) leafminers only. Thorough coverage of both upper and lower leaf surfaces is important. Not for edible crops. Do not apply more than 6 times in 12 months. See label for application types, use restrictions, and resistance management. Entrust Apply early when stippling or mining of leaves is first observed and repeat until infestation is controlled. Three sequential applications at 7-day intervals can maximize control. Addition of a nonionic spray adjuvant enhances control. Do not apply >6 times in a 12-month period, regardless if other insect pests are also being treated. Never make more than 3 consecutive applications. Can use on herbs and vegetable transplants. Toxic to bees. Can use on herbs and vegetable transplants. See label for application types, use and rate restrictions.

149 Table 11.5 Insecticides for Leafminer Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Thiamethoxam 4A Neonicotinoid Flagshiop 0.22 G 12 Systemic product - allow a minimum of one week for smaller plants to translocate to feeding sites of the target pest. If leaching, allow at least 7 days after watering-in for maximum uptake. See label for details, application types and rates. Flagship 25 WDG Apply to foliage or soil or growing substrate. Product applied to foliage is rapidly absorbed/ distributed for rapid control of foliar feeding insects. Product applied to soil will kill soil pests upon contact or ingestion; will also be readily taken up by plant roots to pest feeding sites. See label for application directions. 140

150 Mealybug Control Identification and damage: Mealybugs are small (1 8 mm long), elongate-oval, soft-bodied insects that are covered with a layer of white, cottony wax. They can be found infesting all parts of a plant, including roots. Most produce short, spine-like filaments along the margins of their bodies, and on some species the posterior filaments can be quite long. Some mealybug pests of greenhouse crops include the citrus mealybug, obscure mealybug, and long-tailed mealybug. Mealybug infestations cause leaf distortion, particularly on new growth. Some species inject a toxin as they feed that can produce brown/necrotic areas on foliage, general yellowing, or leaf drop. Their production of white cottony wax and their very presence on leaf axils or undersides of leaves detract from the appearance of the plant. Monitoring: Early detection is important. Examine foliage, petioles, and stems of plants for presence of mealybugs. Inspect the lips of containers as well as drainage holes. Mealybugs produce copious amounts of honeydew which can be found on foliage before the resulting sooty mold. Because ants can be attracted to honeydew as with soft scales, their presence may signal a mealybug infestation. Treatment: Beneficial insects tend to attack specific mealybug species, so identification of the mealybug is important prior to release. If releasing beneficial insects, do so prior to damaging pest population levels and remember to only use pesticides listed as having minimal impact on natural enemies. Immature mealybugs lack their protective waxy coating and are easier to control, especially with contact insecticides. Systemic products are often applied preventatively on a 3 to 4 week schedule. 141

151 Table 11.6 Insecticides for Mealybug Control Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Acephate 1B Organophosphate 1300 Orthene TR 24 Total release cans. Best to apply in early evening when foliage is dry. Best results when greenhouse temperatures are between 60 and 80 F. Ventilate geenhouse before reentry. Acephate 90 Contact insecticide. Do not apply to poinsettias after bract formation or to roses and chrysanthemums with open blooms. See label for phytotoxicity potential, including roses and mums with open flowers. Acephate 97Up Systemic with ingestion action. For use on limited crops e.g. only labeled in greenhouse for anthurium, cacti, carnations, foliage plants, chrysanthemums, orchids, roses, and poinsettias. Do not apply through any irrigation system. Do not apply to freshly rooted cuttings. Do not apply to poinsettias after bract formation, or to roses or chrysanthemum in flower. See label for phytotoxicity potential. Toxic to bees & birds. Orthene TT&O (Turf, Tree, and Ornamental) 97 WP Systemic. For use on limited crops - see label. Not for cut flowers. Do not apply with a low pressure hand wand. Do not apply to poinsettias after bract formation or to roses or chrysanthemums in flower. Do not apply to freshly rooted cuttings. 142

152 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 143 Reentry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 30 SG 12 Contact insecticide with translaminar activity. Thorough coverage is important. The addition of a surfactant may improve efficacy. Do not overhead irrigate for 6 hrs after application. Do not make more than 4 applications per year and do not reapply more than once every 7 days. TriStar 8.5 SL Contact and translaminar activity. Water-soluble bags applied as a foliar spray. Do not make more than 5 applications per year and do not reapply more than once every 7 days. Toxic to bees. Azadirachtin NC Botanical Aza-Direct 4 IGR. By contact or AzaGuard Azamax (=NeemAzal) Azatin O Bayer/Bonide neem oil concentrate Molt-X AzaSol Azatrol Ecozin Plus 1.2% ME Ornazin 3% EC 12 See above. ingestion as a repellent, antifeedant, and interference with the molting process. May repel adults. Will break down in the spray solution if ph >7.0 and/or not used within 8 hrs. AzaSol: May be applied to any food crop. High percent active ingredient and water solubility; need thorough coverage. Azatin XL: Apply to moderately moist soils. Azatrol: May reduce the waxy bloom on certain ornamental plants. Ecozin Plus: Only for herbs and vegetables in greenhouse.

153 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Azadirachtin Pyrethrins Beauveria bassiana Class Trade Name (Formulation) Reentry Interval (hours) Comments 18B 3A Botanical Pyrethroid Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Kills by interfering with the molting process and as an adulticide. Effective on all insect life stages. Do not apply directly to or near water, storm drains or drainage ditches. Do not apply when windy. Do not apply >1 time/ day. Or >10 times per season. NC Microbial Botanigard 22 WP 4 Insect-specific fungus. Mycotrol O (WP) Do not tank mix with fungicides. Acts by contact; thorough coverage is essential. Needs relative humidity greater than 70 % and F for 8-10 hrs. Normally takes 3-7 days for insects to die and 7-10 days after first spray to see a reduction in an insect population. Do not tank mix with fungicides. Product may be used as a pre-plant dip for cuttings. For soil applications do not apply to water-saturated soils. See label for plant list, rates, and specific instructions. Do not treat poinsettias in bract. Note: Formulated for application without additional wetting agents and spreaders. 144

154 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. Best to apply during early evening when foliage is dry and temperature is between F. Ventilate greenhouse before reentry. Do not reapply product within 48 hrs of a previous application. Menace GC 7.9% F Contact insecticide. Thorough coverage of plants is important. Do not apply through any irrigation system. Do not allow runoff to occur. Talstar P (Professional) (F) Talstar Select Up-Star SC Wisdom F Thorough coverage is important. Foliar application. Do not apply to food crops. Do not apply through any irrigation system. Thorough coverage is important. Do not apply through irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can tank mix with plant growth regulators. Do not apply through irrigation system. Use as a foliar application. Can use as a drench application for larval control. Thorough coverage is important. Do not apply through any irrigation system. Do not allow the product to enter any drain during or after application. 145

155 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Buprofezin 16 Buprofezin Talus 70 DF 12 IGR: suppresses egglaying and controls immature stages. Make no more than 2 applications per season. Do not apply through any irrigation system. Apply as soon as mealybug activity is observed. Chlorpyrifos 1B Organophospate DuraGuard ME 24 Microencapsulated formulation. Can apply as a foliar spray and as a coarse spray to soil surface. Caution on roses, variegated ivies, and poinsettias. Do not use on kalanchoes. Direct treatment to open blooms may cause petal drop. Chlorpyrifos and Cyfluthrin Chromobacterium subtsugae strain PRAA4-1 1B 3A Organophosphate Pyrethroid Duraplex TR (=Descriptor Total Release Insecticide) 24 For wholesalers only. Micro Total Release spray; contact action. Apply when foliage is dry and temperature is between F. Do not apply through irrigation system. Do not apply under conditions of extreme heat or drought stress. Available in 2 oz container that treats up to 3,000 ft 2. UN Biological Grandevo 4 Contact biological stomach poison. Proper timing targeting newly hatched larvae is important. Apply to nonblooming plants. Thorough coverage is important. See label warning if mixing with other pesticides. Can use on greenhouse herbs and vegetables. 146

156 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 147 Reentry Interval (hours) Comments Cyfluthrin 3A Pyrethroid Decathlon 20WP 12 Do not apply through any type of irrigation system. A spreader-sticker may enhance coverage of hard to wet leaf surfaces. Good coverage is necessary. See label for specific rates and instructions. Dinotefuran 4A Neonicotinoid Safari 2 G 12 Contact and systemic insecticide. Foliar application provides suppression or regulation only. Do not apply until after target plants are through blooming and pollen and nectar are no longer present. No more than 2 foliar or broadcast applications and/or 1 soil application may be made per crop per year. Only apply soil drench to moist substrate. Do not apply to dry or saturated substrate. Do not apply foliar sprays to plants that have received a soil drench. Toxic to bees. Fenoxycarb 7B Fenoxycarbs Prescription Treatment Preclude TR Fenpyroximate 21A METI-acaricides Mitochondria electron transport inhibitor 12 IGR. Micro encapsulated release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days. Akari 5SC 12 Contact. Only vegetables on label are tomatoes and cucumbers. Spray water should be buffered to ph 5 7. Can be used as a dip for flower and foliage cuttings. Do not use through any irrigation system. See label for plant safety information.

157 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Flonicamid 9C Pyridinecarboxamide Trade Name (Formulation) Imidacloprid 4A Neonicotinoid Amtide Imidacloprid 2F T&O Bounty (restricted use) 148 Reentry Interval (hours) Comments Aria 12 Water-soluble packets. Insects stop feeding quickly but may remain on plants for up to 5 days. Product has residual control. Do not apply this product more than 2 times consecutively before rotating. Certain pansy cultivars have exhibited sensitivity to product. Discus Tablets Imidacloprod 2F Select Lada 2F 12 Systemic. Protection period is reduced if media has >30 50 % bark content. Do not apply to waterlogged or saturated soils. Do not apply while bees are foraging. Do not apply to plants in flower (only apply after all petals have fallen off). See label for rates/restrictions based upon container size and application type. Tablets are formulated to provide consistent delivery of active ingredient over time. Release of active ingredient is dependent on presence of adequate soil moisture. For herbs in greenhouse only (7 day PHI). See AmTide. Do not apply through irrigation system. Do not foliar apply following soil application in same crop. Systemic. Can incorporate into the substrate before planting. Caution on ferns, Crassula, petunias, and lantana.

158 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Imidacloprid + Cyfluthrin Class Trade Name (Formulation) Reentry Interval (hours) Comments 4A Neonicotinoid Lada 75 WSP 12 For containers only. See label. Mallet 2F T&O Not to be used more than once every 16 weeks. See label for application options, rates, and details. Mallet 75 WSP Soil treatment only. Do not make more than 5 applications per year. Mantra 1G For crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. Mantra 2F Do not apply through any type of irrigation system. Mantra 60 WSP Protection period is reduced if media has >30 50 % bark content. See label for use restrictions. Marathon 1%G Apply when root systems are well established. See label for plant list, rates, and specific instructions. Marathon II (F) Applications can be made before egg-laying activity of target pests. 4A Discus N/G 12 Contact & systemic 3A insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Make applications to flowering plants during times when pollinating insects are not present. See label for application types, rates, and details. 149

159 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Insecticidal soap NC Potassium salts of fatty acids Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Trade Name (Formulation) Insecticidal Soap (Bayer, Bonide, Earth-Tone, Natural Guard, Safer) DES-X M-Pede 150 Reentry Comments Interval (hours) 12 Kills by contact so complete coverage is essential. Caution on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings for phytotoxicity. Do not use on new transplants, unrooted cuttings, or plants stressed by drought or heat (>90 F). Apply early in morning or evening or when overcast; do not spray during full sun. Do not apply more than once per day. Do not spray open blooms or partially open flower buds. See label for details on plant safety and tank mixing. NC Biological NoFly WP 12 Contains live spores of an insect-killing fungus. For non-food crops. Foliar application. Works best at temperatures between F with high humidity. Typically takes 3-7 days for insects to die. Avoid breathing spray mist. May cause moderate eye irritation. Do not apply when bees are actively foraging. See label for application information, storage, and details. Preferal See above. Most effective when use begins at first appearance of pest, before high populations develop. Frequent scouting is critical to success. Follow label directions.

160 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Kinoprene 7A Juvenile hormone analogues Lambdacyhalothrin Trade Name (Formulation) Reentry Interval (hours) Comments Enstar AQ 4 IGR; see label for specific instructions for root mealybug control. Thorough coverage is necessary. Some varieties of roses show delayed damage. See label for specific rates and instructions. 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact insecticide. Thorough coverage of all plant parts is important; a spreader-sticker is recommended. Do not apply through any type of irrigation system. Do not mix with EC formulations or oils. Neem oil NC Clarified hydrophobic extract of neem oil Triact 70 4 Apply before insects or eggs are present in large numbers. Do not apply to wilted or stressed plants, or new transplants prior to root establishment. Caution if applying to hibiscus flowers. Do not spray on impatiens flowers or on cut roses. Do not make more than 5 applications per year and do not reapply more than once every 7 days. Product is also a fungicide. See label for specifics. 70% Neem Oil See above. Do not exceed 1.0 % rate in the greenhouse. 151

161 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Oil, Horticultural (paraffinic hydrocarbon oils; petroleum oil, soybean oil, vegetable oil) Oil of rosemary and peppermint Class Trade Name (Formulation) NC Oil Bonide All Seasons Horticultural Spray (mineral oil) Golden Pest Spray Oil (soybean oil) JMS Stylet Oil # (Paraffinic/mineral oil) Lesco Horticultural Oil (mineral oil) Monterey Horticultural Oil (mineral oil) PureSpray Green, Saf-T-Side (petroleum oil) RTSA Horticultural Oil (mineral oil) Suffoil-X (paraffinic oil) TriTek (mineral oil) Ultra-Pure Oil (petroleum oil) Reentry Comments Interval (hours) 4 Complete coverage needed. Horticultural oil sprays applied to new leaf growth may inhibit egg laying, but must be repeated on a weekly basis during each flush cycle. Do not apply if plants are under any stress or during periods of prolonged high temperatures combined with high relative humidity. Avoid spraying in greenhouses under overcast conditions. Do not exceed label rates or apply more often than recommended. Effectiveness at temperatures below 50 F is reduced. Do not apply through any irrigation system. See label for cautions if using with/before/following application of certain products and for use restrictions and mixing cautions. # Only labeled for mums, poinsettias, dieffenbachia, & philodendron. NC Botanical Ecotec 4 Contact insecticide; labeled for herbs, vegetables, and woody plants. Use an adjuvant. Thorough coverage of all plant parts is important. Repeat application every 5-7 days. Do not use if temps are >90 F. 152

162 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Permethrin 3A Pyrethroid Astro 12 Contact insecticide. Permethrin 3.2 Ag Thorough coverage of all plant parts is important. Direct application to blooms may cause browning of petals. Marginal leaf burn may occur on salvia, dieffenbachia, and Pteris fern. Pyrethrins 3A Pyrethrin Pyganic Crop Protection 12 See label for rates and applications. Herbs are listed on the label. Buffer final spray mix to a ph of In the greenhouse, do not exceed maximum application rate of.0036 lbs a.i./1,000 sq. ft. or 1.18fl. oz./1,000 sq. ft. Do not apply more than once per day. Pyrethrins and Piperonyl butoxide 3A Pyrethrin Pyrenone 5.0 Crop Spray (EC) Pyronyl Crop Spray (Prentox) Pyreth-It Formula 2 Pyrethrum TR 12 A botanical insecticide plus a synergist to flush insects out of hiding and into contact with spray residues. See label for details. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can be tank mixed with other insecticides. See label. See above. No more than 10 applications/season in greenhouse. See label. See Pyrenone 5.0 Crop Spray above. Micro total release aerosol formulation for greenhouses that treats up to 3,000 ft 2. See label for specific instructions 153

163 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 154 Reentry Interval (hours) Comments Pyrifluquinazon Rycar 12 Contact and translaminar insecticide. Only for non-food crops. Causes immediate stop-feed. Thorough spray coverage needed. Do not apply through irrigation system. Do not harvest cut flowers for 48 hrs after spraying. Do not compost treated plant material. Do not allow spray solution to run off outside of application area. Do not make more than 2 applications per crop cycle. Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for suppression of eggs, nymphs and pupae. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettias in bract. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. Spirotetramat 23 Sulfoximine Kontos 12# Contact, stomach poison, systemic and translaminar insecticide for both knockdown and residual control. Not a neonicotinoid. Provides knockdown and up to one month of residual control. Do not apply to edible crops or geranium. Start treatments prior to establishment of high pest populations and reapply on an as-needed basis. See label for important plant safety information. #See label for drench REI.

164 Table 11.6 Insecticides for Mealybug Control (continued) Chemical Name IRAC Code Sulfoxaflor (IsatoxR) + Spinetorum 4c 5 Class Trade Name (Formulation) 155 Reentry Interval (hours) Comments Sulfoximine XXpire WG 12 Has systemic and translaminar activity. Not a neonicotinoid. Provides knockdown and up to one month of residual control. Do not make more than 2 consecutive applications. Do not make more than 4 applications per year. Tau-fluvalinate 3A Pyrethroid Mavrik Aquaflow 12 Buffer spray water to ph 5-7. Do not apply more than 4 sprays per month. May work slowly on some species; allow 3 4 days to evaluate. Caution on roses and poinsettias. Can use as a dip for cuttings. May cause respiratory allergic response. Thiamethoxam 4A Neonicotinoid Flagship 0.22 G 12 Systemic product; allow at least one week for smaller plants to translocate to feeding sites. If leaching, allow at least 7 days after watering-in for maximum uptake. Flagship 25 WG Apply to foliage or substrate. Product applied to foliage is rapidly absorbed for rapid control of foliar feeding insects. Product applied to soil will kill soil pests upon contact or ingestion; will also be readily taken up by plant roots to pest feeding sites. Tolfenpyrad 21A METIinsecticides Hachi-Hachi 12 Contact insecticide. Phytotoxic to blooms and some plants. Allow at least 10 days between applications. Do not apply to gypsophilia, impatiens, salvia, or poinsettias in bract.

165 Mite Control Mites are closely related to spiders. Since they are not an insect, many insecticides do not control them effectively. Two different types of mites are typically found in the greenhouse: Tarsonemid mites (broad mites, cyclamen mites), and Tetranychid mites (twospotted spider mites, Lewis mites, and carmine mites). A separate control chart appears for each mite group. A. Tarsonemid Mites: Broad mite and Cyclamen mite Identification and damage: Broad mites and cyclamen mites are closely related and look very similar. Both are white and very small with setae covering their body. The males have 6 legs that are used for walking and the two hind legs turn upward to grasp females and carry immature females around. Both stages cause similar damage. Broad mite can be distinguished from cyclamen mites by their egg stage. Broad mite eggs are covered with bumps that look like a row of diamonds and are best seen using a dissecting microscope. Adults and larvae are smaller than the cyclamen mites and walk rapidly on the underside of leaves. The development of broad mites is favored by high temperatures of 70 to 80 F. Broad mites can complete their life cycle in as little as one week. Females lay from 30 to 75 eggs. Monitoring: Broad mites can affect a number of ornamentals including sweet potato vine, gerbera daisy, New Guinea impatiens, salvia, ivy, verbena and zinnia. They may migrate to peppers or tomatoes. Look for characteristic damage to new growth or leaf edges: curling and twisting of new growth on plants/curling downward. Terminal buds may be killed. As they feed, broad mites inject toxic saliva which causes the characteristic twisted and distorted growth. Do not confuse broad mite injury with herbicide injury, boron deficiency or physiological disorders. With a 20X hand lens, inspect the curled and cupped leaves for mites. Treatment: Sprays must be fine mists to penetrate the cryptic areas in plants where mites are found. Broad and cyclamen mites are not spider mites and are not necessarily controlled with the same materials used for spider mites (with a few exceptions). 156

166 Table 11.7 Miticides for Tarsonemid (Broad, Cyclamen, Bulb Scale, and Fern) Mite Control Chemical Name IRAC Code Class Trade Name (Formulation) Abamectin 6 Avermectin Abamectin SPC 0.15 EC Avid 0.15 EC Ardent 0.15EC Merlin (Phoenix Merlin) Lucid Minx Re-entry Comments Interval (hours) 12 Foliar spray with translaminar properties. For Tarsonemid mites, repeat applications to new tissue may be necessary to maintain control. Do not apply through any type of irrigation system. Caution on roses, chrysanthemums, and gerberas. Not recommended for use on ferns or shasta daisies. Do not get in eyes, on skin, or on clothing. Avoid breathing spray mist. See label for plant safety and resistance management. Acequinocyl 20B Shuttle O 12 Contact miticide. Provides quick knockdown and long residual activity. Do not use on impatiens or miniature roses. See label for specific instructions and details. Bifenazate Abamectin UN Sirocco (=Prevamite O) 12 Thorough coverage of foliage is essential; young immatures must be contacted by the spray. Do not make >2 applications per crop per year. See label for details 157

167 Table 11.7 Miticides for Tarsonemid (Broad, Cyclamen, Bulb Scale, and Fern) Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Bifenthrin 3A Pyrethroid Menace GC 7.9% Flowable (F) Talstar Select Up-Star SC Wisdom F Re-entry Comments Interval (hours) 12 Contact insecticide. Thorough coverage of all plant parts is important. Do not apply through any irrigation system. Do not make applications during the rain. Do not allow runoff or dripping to occur. Thorough coverage is important. Do not apply through any type of irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can tank mix with plant growth regulators. Do not apply through irrigation system. Do not apply if rain is expected within 12 hrs. Do not apply if wind is >10mph. Do not apply when a temperature inversion exists. Use as a foliar application. Can use as a drench application for larval control. See label for specific instructions. Thorough coverage is important. Do not apply through any irrigation system. Do not allow product to enter any drain during or after application. See label specific instructions. 158

168 Table 11.7 Miticides for Tarsonemid (Broad, Cyclamen, Bulb Scale, and Fern) Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 159 Re-entry Interval (hours) Comments Chlorfenapyr 13 Pyrrole Pylon 12 Contact; stomach poison with translaminar activity. For ornamentals and fruiting vegetables. Thorough coverage is needed. Do not apply >3 times in a season. Not ovicidal. Toxic to bees; apply prior to bloom. Phytotoxicity caution on carnations, dianthus, kalanchoe, roses, poinsettias, salvias and zinnias. See label for application details (including plugs). Pylon TR See above for Broad mite only. Total release product in 2 oz container treats up to 3,000 ft 2. Do not compost any discarded treated plant material. See label for precautions. Fenazaquin 21 METI-acaricides Magus 12 Kills by contact and ingestion for both immature and adult mites. Thorough coverage is required. Do not use on roses. No more than one application per crop. Fenpyroximate 21A METI-acaricides Akari 5SC 12 For greenhouse ornamentals, tomatoes, cucumbers and interiorscapes only. Spray water should be buffered to ph 5 7. Can use as a dip for flower and foliage cuttings. Do not use through irrigation system.

169 Table 11.7 Miticides for Tarsonemid (Broad, Cyclamen, Bulb Scale, and Fern) Mite Control (continued) Chemical Name IRAC Code Class Insecticidal soap NC Potassium salts of fatty acids Lambdacyhalothrin Oil of rosemary and peppermint Trade Name (Formulation) 160 Re-entry Interval (hours) Comments M-Pede 12 Kills by contact so complete coverage is essential. Caution using on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlingssee label. Do not use on new transplants, unrooted cuttings, or plants stressed by drought or heat (>90 F). Apply early in morning or evening or when overcast; do not spray during full sun. Do not spray open blooms or partially open flower buds. See label for on plant safety and tank mixing. 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact insecticide for adults. Thorough coverage of all plant parts is important; a spreader-sticker is recommended. Do not apply through any type of irrigation system. Do not mix with EC formulations or oils. NC Botanical Ecotec 4 Contact insecticide; labeled for herbs, vegetables, and woody plants. Use an adjuvant. Thorough coverage is important. Repeat application every 5-7 days. Do not use if temps are >90 F..

170 Table 11.7 Miticides for Tarsonemid (Broad, Cyclamen, Bulb Scale, and Fern) Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 161 Re-entry Interval (hours) Comments Pyridaben 21A METI-acaricides Sanmite WP 12 For all stages; most effective on juvenile mites. Good coverage of the upper and lower leaf surfaces is recommended. Do not apply to geraniums and impatiens. Do not use in successive miticide applications during the same cropping cycle. Spiromesifen 23 Tetronic and tetramic acid derivatives Judo 12 For all mite stages, but is most effective on juvenile stages. For best results good coverage of the upper and lower leaf surfaces is recommended. Do not apply to geraniums, peperomia, dracaena, certain rose varieties, ivy, and fuchsia. See label for plants with phytotoxicity potential. Do not use in successive miticide applications during the same cropping cycle. Spirotetramat 23 Kontos 24# Not a neonicotinoid. Contact, stomach poison, systemic and translaminar insecticide for knockdown and up to one month residual control. Do not apply to edible crops or geraniums. Start treating before high populations develop; reapply asneeded. #See label for drench REI.

171 Mite Control (continued) B. Tetranychid Mites: Twospotted spider mite, Lewis mite and Carmine mite Identification and damage: Tetranychid mites include twospotted spider, Lewis mite and carmine mites. Adult are slightly orange in color and very small (1/50th inch or 0.5mm). Most spider mites are found on the underside of leaves. Feeding injury (called stippling) often gives the top leaf surfaces a mottled/speckled, dull appearance. Leaves then turn yellow and drop. Large populations produce visible webbing that can completely cover the leaves. Buds may become distorted. Eggs are laid singly, up to 100 per female, during her 3- to 4-week life span. Eggs hatch into larvae in as few as 3 days. The egg to adult life cycle can be completed in 7 to 14 days depending upon temperature. Hot and dry conditions (>81 F) favor rapid spider mite development. Monitoring: Pay close attention to plants growing on the south side of a greenhouse as well as warm locations near heaters or steam pipes. Hanging baskets in the upper canopy of the greenhouse also tend to be very susceptible. Check for mites weekly by examining foliage using a hands-free magnifier (Optivisor) or hand lens. Be sure to examine the undersides of leaves. Adult mites are not found on sticky cards. Mites often develop as localized infestations on particular groups of plants. Weeds should be removed/controlled as they can harbor twospotted mites. Treatment: Avoid overfertilization. If using beneficial predaceous mites or other natural enemies, release prior to damaging pest population levels. If using mite growth regulators (TetraSan), application must occur prior to mite population buildup. Sprays must be fine mists to penetrate the cryptic areas in plants where mites are found. Translaminar miticides are therefore recommended. Thorough coverage is necessary with repeated applications. Most miticides are not effective against the egg stage, so repeat applications are necessary. Remember to rotate insecticides, as resistance is common. 162

172 Table 11.8 Miticides for Spider Mite Control Chemical Name IRAC Code Class Trade Name (Formulation) Abamectin 6 Avermectin Abamectin SPC 0.15 EC Avid 0.15 Ec Ardent 0.15 EC Merlin (Phoenix Merlin) Lucid Minx 163 Re-entry Comments Interval (hours) 12 Foliar spray; translaminar properties. Repeat applications to new tissue may be necessary to maintain control. Do not apply through any irrigation system. Caution on roses, chrysanthemums, and gerbera. Do not use on ferns or Shasta daisies. Avoid breathing spray mist. See label for details, plant safety and resistance management. Acequinocyl 20B Acequinocyl Shuttle O 12 Contact miticide. Provides quick knockdown and long residual activity. Do not use on impatiens or miniature roses. See label for specific instructions. Acephate 1B Organophosphate 1300 Orthene TR 24 Total release cans. Best to apply in early evening when foliage is dry and greenhouse temperatures are between F. Ventilate greenhouse before reentry. See label for specific instructions. Azadirachtin (neem oil) 18B Botanical Aza-Direct 4 IGR. Controls by AzaGuard Azamax (=NeemAzal) Azatin O Bayer/Bonide Neem Oil Concentrate Azatin XL AzaTrol contact or ingestion as a repellent, antifeedant, and interference with the molting process. Use as a drench or as a foliar spray to repel adults. Do not use in spray tank mixtures with ph >7.0. Use promptly after mixing. See above. Apply to moderately moist soils. See above. May reduce the waxy bloom on certain ornamental plants.

173 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Azadirachtin Pyrethrins 18B 3A Botanical Pyrethroid Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Kills by interfering with the molting process and as an adulticide. Effective on all mite life stages. Do not apply directly to or near water, storm drains or drainage ditches. Do not apply >1 time/ day. Or >10 times per season. Bifenazate UN Bifenezate Floramite SC 12 Contact; active against all life stages (also has ovicidal activity). Apply as soon as mites appear; will provide residual control for up to 28 days. Do not use in successive applications. Make only one application of product before rotating to products of an alternative chemical class, and use at least two alternative products between treatments. Do not make more than 2 applications per crop per year. Product degrades rapidly when mixed and stored with alkaline water of high temperature (122 F). See label for complete plant list, rates, and specific instructions. Toxic to bees. Bifenazate Abamectin 6 + UN 25 Sirocco (=Prevamite O) 12 Thorough coverage of foliage is essential; young immatures must be contacted by the spray. Do not make >2 applications per crop per year. 164

174 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. Best to apply in early evening when foliage is dry and temperature is between F. Ventiliate greenhouse before reentry. Do not reapply product within 48 hrs of a previous application. Menace GC 7.9% F Contact insecticide. Thorough coverage is important. Do not apply through irrigation system. Do not spray to runoff. Talstar Select Thorough coverage is important. Do not apply through any irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can tank mix with plant growth regulators. Up-Star SC Do not apply through Wisdom F irrigation system. Chlorfenapyr 13 Pyrrole Pylon 12 Contact; stomach poison with translaminar activity. For ornamentals and fruiting vegetables. Thorough coverage is needed. Do not apply >3 times in a season. Not ovicidal. Toxic to bees; apply prior to bloom. Caution on carnations, dianthus, kalanchoe, poinsettias, roses, salvias and zinnias. See label for application details (including plugs). Pylon TR See above. Total release cans. A 2 oz can treats up to 3,000 ft 2. Do not compost any treated plant material. 165

175 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 166 Re-entry Interval (hours) Comments Chlorpyrifos 1B Organophosphate DuraGuard ME 24 Microencapsulated formulation. Can apply as a foliar spray and as a coarse spray to substrate surface. Caution on poinsettias, roses, and variegated ivies. Do not use on kalanchoes. Direct treatment to open blooms may cause petal drop. Chlorpyrifos Cyfluthrin Chromobacterium subtsugae strain PRAA4-1 1B 3A Organophosphate Pyrethroid Duraplex TR (=Descriptor Total Release Insecticide) 24 For wholesalers only. Micro Total Release can; contact action. Apply to dry foliage in early evening when temperature is between F. Do not apply through irrigation system. Do not apply under conditions of extreme heat or drought stress. A 2 oz container treats up to 3,000 ft 2. UN Biological Grandevo 4 Contact biological stomach poison. Proper timing targets newly hatched larvae. Apply to non-blooming plants. Thorough coverage is important. See label warning if mixing with other pesticides. Can use on greenhouse herbs and vegetables. Clofentezine 10A Clofentezine Ovation SC 12 Active on mite eggs and early mite stages. It has shown activity and persistence up to 45 days. Tank mix with an adult miticide if adult activity. See label for low volume applications. Product is magenta in color and may leave a residue. Thorough coverage necessary. Use only once per cop cycle.

176 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Cyflumetofen 25 METI betaketronitrile Emamectin benzoate Trade Name (Formulation) 167 Re-entry Interval (hours) Comments Sultan 12 Contact; selective activity on spider mites only. Thorough coverage is important. Do not apply if irrigation event is expected within 1 hr following application. Do not make more than 2 applications per crop per year. Compatible with most biological control organisms used for mite control. 6 Enfold 12 Mite suppression only. Contact and ingestion activity, pests stop feeding and die after 2-4 days. Apply before populations reach damaging levels. Thorough spray coverage is essential. Avoid application when the temperature is high and/or the humidity is low. Toxic to bees. Do not apply this product through any type of irrigation system. Etoxazole 10B Etoxazole TetraSan 5WDG 12 Translaminar. Kills nymphs and eggs. Treated adults do not produce viable eggs. Can apply in combination with miticide for adults. Apply no more than 2 times per cropping cycle or no more than twice per 6 months. Do not apply to poinsettias after bract formation. Beethoven 24 Total release cans treat up to 3,000 ft 2. For ornamentals only. Contact and translaminar activity. Do not apply to plants under stress.

177 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 168 Re-entry Interval (hours) Comments Fenazaquin 21 METI-acaricides Magus 12 Kills by contact and ingestion for both immature and adult mites. Thorough coverage is required. Do not use on roses. No more than one application per crop. See label for information on plant safety. Fenbutatin-oxide 12B Organotin miticide Fenoxycarb 7B Fenoxycarbs Prescription Treatment Brand Preclude TR ProMITE 50 WP 48 Contact miticide. Apply when mite populations are just beginning to build. Thorough coverage is important; best if daily temperature averages >70 F. Do not use in sprayers that have any residues of boron or chlorine. Apply only to chrysanthemum pre-bloom and poinsettias pre-bract. Some ferns, mums, and other ornamentals have exhibited phytotoxicity. See label for complete plant list, rates, and specific instructions. 12 Mite growth regulator. Micro-total release. Store cans >65 F for 24 hrs before release. Do not use more than every 7 days. Fenpyroximate 21A METI-acaricides Akari 5SC 12 For greenhouse ornamentals, tomatoes, cucumbers and interiorscapes only. Good spray coverage needed. Spray water should be buffered to ph 5 7. Can use as a dip for flower and foliage cuttings. Do not use through any irrigation system. See label for plant safety information.

178 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Hexythiazox 10A Insect growth regulator Insecticidal Soap Isaria fumosorosea (previously known as Paecilomyces fumosoroseus Trade Name (Formulation) 169 Re-entry Interval (hours) Comments Hexygon DF 12 Mite growth inhibitor. Controls eggs and immature stages. Will also control immature motile stages that are sprayed or move onto treated surfaces. Will not kill adults, but treated adults will not produce viable eggs. Not labeled for chemigation. Product has some residual activity. See label for details. NC Potassium salts DES-X 12 Kills by contact so of fatty acids complete coverage is M-Pede essential. Caution on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings for phytotoxicity (see label). Do not treat new transplants, unrooted cuttings, or plants stressed by heat (>90 F) or drought. Apply early in morning or evening or when overcast; do not spray in full sun. Do not apply more than once per day. Do not spray open blooms or partially open flower buds. See label on tank mixing. NC Preferal 12 Contains live spores of an insect-killing fungus. Mites come into contact with spores and can be infected. Foliar spray. Use before high populations develop. Frequent scouting is critical. Most effective when relative humidity is >80 % for 8-10 hrs.

179 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Lambdacyhalothrin Metarhizium anisopliae strain F52 Class Trade Name (Formulation) 170 Re-entry Interval (hours) Comments 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact miticide for adults. Thorough coverage is important; a spreadersticker is recommended. Do not apply through any irrigation system. Do not mix with EC formulations or oils. NA Biological MET 52 EC 0-4 For use as foliar application. Do not apply on poinsettias after bract formation. Apply to moist substrate and keep moist. See label for information and rates. Methiocarb 1A Carbamate Mesurol 75WP 24 Contact miticide. Do not apply with oil or foliar fertilizer. Effectiveness may be reduced when the spray solution phis >7. Do not make more than 2 applications per year per crop; must apply at least 10 days apart. Neem oil NC Oil Triact 70 4 Apply before mites or eggs are present in large numbers. Do not exceed 1.0% rate in the greenhouse. Do not apply to wilted or otherwise stressed plants, or to newly transplanted materials before roots established. Best not to use on cut roses. Do not spray impatiens flowers. Reapply every 7-21 days until pest pressure is over. Caution when treating hibiscus flowers. Product is also a fungicide. 70% Neem Oil See above. Do not exceed 1.0% rate in greenhouse.

180 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Oil, Horticultural (paraffinic hydrocarbon oils; petroleum oil, soybean oil, vegetable oil) Oil of rosemary and peppermint Class Trade Name (Formulation) NC Oil Bonide All Seasons Horticultural Spray Oil (mineral/ paraffinic oil) Golden Pest Spray Oil (soybean oil) Lesco Horticultural Oil # (mineral oil) Monterey Horticultural Oil (mineral oil) Pure Spray Green (mineral oil) RTSA Horticultural Oil (mineral oil) Saf-T-Side Spray Oil (petroleum oil) Suffoil-X (petroleum oil) Summit Year Round Spray Oil (mineral oil) SunSpray Ultra Fine Oil, TriTek (mineral oil) Ultra-Pure Oil (mineral oil) Re-entry Comments Interval (hours) 4 Contact miticide; works via suffocation. Thorough coverage of all plants is very important. Cover both top and bottom of all of the leaves and stems until wet but without significant runoff. Be cautious on open blooms. Foliar injury may occur if applied during hot, humid conditions. Do not tank mix with more than one pesticide. Do not apply through irrigation systems. Do not spray more than once per week. Do not spray when there is an obvious moisture deficit in leaves or plants are under stress. Test for phytotoxicity for each plant variety before treating. Do not exceed four applications per growing season. Do not use in combination or immediately before/after spraying fungicides or any product containing sulfur. Do not use with carbaryl (Sevin) or dimethoate (Cygon). See label for phytotoxicity safety. NC Botanical Ecotec 4 Contact insecticide; labeled for herbs, vegetables; woodies. Use an adjuvant. Thorough coverage of all plant parts is important. Repeat application every 5-7 days. Do not use if temperatures are >90 F. 171

181 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Pyrethrins Piperonyl butoxide (PBO) Class Trade Name (Formulation) 3A Pyrethrin Pyrenone Crop Spray Pyrethrum TR 172 Re-entry Comments Interval (hours) 12 Botanical miticide with synergist to flush insects out of hiding and into contact with spray residues. Apply to dry foliage. Do not use on cyclamen or nasturtium. Micro total release aerosol formulation for up to 3,000 ft 2. Pyridaben 21A METI-acaricides Sanmite 12 Contact; water soluble packets. Thorough coverage is important. Do not apply through any irrigation system. May be fatal if inhaled. Do not use in successive miticide applications; rotate. Spinosad 5 Spinosyn Conserve SC 4 Suppression only. Contact and stomach poison; thorough coverage is important. Not for edible crops. Apply when mites first observed before damage is severe. A nonionic adjuvant enhances control. See label for application types and rate restrictions. Entrust Apply before webbing and populations become severe. Reapply after 7-10 days (3-5 days in greenhouses) to contact newly hatched nymphs; repeat until under control. Thorough coverage is critical. A nonionic spray adjuvant may enhance control. Do not apply >6 times in a 12-month period. Do not treat more than 3 consecutive times. Toxic to bees.

182 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Class Spiromesifen 23 Tetronic and tetramic acid derivatives Trade Name (Formulation) 173 Re-entry Interval (hours) Comments Judo 12 Active on all mite development stages, but is most effective on juvenile stages. For best results good coverage of the upper and lower leaf surfaces is recommended. Do not apply to dracaena, geraniums, peperomia, certain rose varieties, ivies, fuchsia and others -- see label for plants with phytotoxicity potential. Do not use in successive miticide applications during the same cropping cycle. Spirotetramat 23 Kontos 24 Contact, stomach poison, systemic and translaminar insecticide for both knockdown and residual control. Not a neonicotinoid. Do not apply to greenhouse grown vegetables other than vegetable transplants Make applications preventatively or when populations are first detected. If spider mite populations are heavy at time of application, control may not be achieved rapidly enough. Apply as a drench, not a foliar spray. If a second miticide application is necessary to achieve control, use a product with an alternative mode of action. Do not apply to edible crops or geranium. Start treatments prior to establishment of high pest populations.

183 Table 11.8 Miticides for Spider Mite Control (continued) Chemical Name IRAC Code Sulfoxaflor (IsatoxR) Spinetorum 4C 5 Class Trade Name (Formulation) Re-entry Interval (hours) Comments Sulfoximine XXPire 12 For suppression of spruce mites and twospotted mites. Mixture gives both knockdown and residual control. Not a neonicotinoid. Has systemic and translaminar activity. Provides knockdown and up to one month of residual control. Do not apply to edible crops. Tau-fluvalinate 3A Pyrethroid Mavrik Aquaflow (F) 12 Contact; thorough coverage needed. May cause respiratory allergic response. Spray water should be buffered to ph 5-7. Do not spray more than 4 times per month. Caution on roses and poinsettias. Can also be used as a dip for flower and foliage cuttings. 174

184 Scale Control Identification and damage: Scale insects are classified as either soft scales or armored scales. Soft scales are larger (2 5 mm) and usually have a circular or oval shape. Colors are usually shades of gray or brown. Soft scales produce honeydew as they feed. The protective waxy cover (teste) cannot be detached from the body of soft scales. Common species include black scale, soft brown scale, and hemispherical scale. Armored scales secrete a hard, waxy cover (shield) over their bodies. Armored scales do not produce honeydew. The protective waxy cover (teste) can be separated from the body of armored scales. Examples include Florida red scale and fern scale. All immature scales, called crawlers, hatch from eggs. The first nymphal instar of both soft and armored scales has functional legs. Soft scale crawlers crawl out over the leaves and stems to feed on the plant, and may move back again. Armored scale crawlers move a short distance from where they were hatched and find a suitable place to settle down and feed. They do not move again for the remainder of their lives. The crawler stage is the most sensitive to insecticides. Scale insects are small, sucking insects that remove sap from plants as they feed. This causes spotting or yellowing of leaves, overall poor plant growth, and dieback. Soft scales can produce distorted foliage from their feeding on young tissue causing the leaves to turn yellow. High populations can cause twigs and branches to die back. Soft scales excrete a sugary product called honeydew which can fall onto leaves and cause them to become shiny and sticky. Honeydew can support the growth of unsightly sooty mold. Armored scales can produce either yellow or brown spots or streaks on the leaves. They can cause general yellowing of the foliage, poor growth, and incrustations of both stems and leaves. In very high populations they can cause twig dieback or even kill the plant. Monitoring: Check foliage and stems for presence of scale covers. The presence of honeydew and sooty mold is a good indication of an infestation. Treatment: Avoid overfertilization. If releasing beneficial predaceous mites or other natural enemies, do so prior to damaging pest population levels. Time all treatments to the susceptible crawler stage. Systemic insecticides have shown better control levels on soft scales than armored scales. 175

185 Table 11.9 Insecticides for Scale Control Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Acephate 1B Organophosphate Acephate Contact insecticide for crawlers. All Acephate Products: Do not apply to poinsettias after bract formation or to roses and chrysanthemums with open blooms. Acephate 97 Up Systemic; ingestion action for crawlers. For use on limited crops only labeled in greenhouse for cacti, anthurium, carnations, chrysanthemums, foliage plants, orchids, roses, and poinsettias. Do not apply through any irrigation system. Do not apply to freshly rooted cuttings. Toxic to bees & birds Orthene TR Total release cans. Best to apply in early evening to dry foliage with greenhouse temperatures at F. Ventilate before reentry. Orthene TT&O 97 (WP) (Turf, tree, & ornamental) Systemic insecticide for crawlers. For use on limited crops - see label. Not for cut flowers. Do not apply with a low pressure hand wand. Apply as crawlers begin to appear; repeat applications, at a 2 week or more interval if there is continuous crawler activity. Do not treat freshly rooted cuttings. 176

186 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 177 Reentry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 30 WSP 12 Contact insecticide; translaminar activity. Thorough coverage is important. Do not irrigate overhead for 6 hrs after application. Test for phytotoxicity if using a surfactant. Do not treat >5 times/year or more than once every 7 days. TriStar 8.5 SL Water-soluble bags as a foliar spray. Do not treat >5 times per year; do not reapply more than once every 7 days. Toxic to bees. Azadirachtin 18B Botanical Aza-Direct 4 IGR. Controls by contact AzaGuard or ingestion as a repellent, Azamax antifeedant, and interference with molting process. (=NeemAzal) Use as a drench or foliar Azatin O spray. May repel adults. Azatin XL Breaks down if spray solution ph >7.0 and/or not Bayer/Bonide Neem Oil Concentrate used within 8 hrs. Aza- Ecozin Plus 1.2% ME Molt-X Guard, Molt-X, and Ornazin 3% EC are for soft scales only. Ecozin Plus Ornazin 3% EC % is only for greenhouse vegetables/herbs. AzaSol 4 See above; for armored and soft scale crawlers. High water solubility; thorough coverage needed. Azatrol See AzaDirect; for armored and soft scale. May reduce waxy bloom on some plants. Azadirachtin & Pyrethrins 3A Pyrethroid Azera 12 Soft scale only. Works by contact or by ingestion. Interferes with molting process and by contact. Do not apply more than once per day or >10 times/ season.

187 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. Best to apply during early evening when foliage is dry and temperature is F. Ventilate greenhouse before reentry. Do not reapply product within 48 hrs of a previous application. Menace GC 7.9% Flowable (F) Talstar P (Professional) (F) Talstar Select Contact insecticide. Thorough coverage of all plant parts is important. Do not apply through any irrigation system. Do not make applications during the rain. Do not apply to runoff. For crawlers only. Foliar applications. Thorough coverage is important. Do not apply to food crops. Do not apply through any irrigation system. For crawlers only. See above. Spreader stickers are not necessary. Do not use on edible plants. Up-Star SC (F) For crawlers only. See Wisdom F Menace information. Buprofezin 16 Buprofezin Talus 70 DF 12 IGR: controls crawler stages. Apply no more than 2 applications per season. Do not apply through any irrigation system. Chlorpyrifos 1B Organophosphate DuraGuard ME 24 Microencapsulated formulation. Caution on poinsettias, camellias, roses, and variegated ivies. Do not use on kalanchoes. May causes petal drop on some open blooms. 178

188 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Chlorpyrifos and Cyfluthrin Chromobacterium subtsugae strain PRAA4-1 1B 3A Class Organophosphate Pyrethroid Trade Name (Formulation) Duraplex TR (=Descriptor Total Release Insecticide) 179 Reentry Comments Interval (hours) 24 For wholesalers only. Micro Total Release spray; contact action. Apply when foliage is dry during early evening when temperature is between F. Do not apply through any irrigation system. Do not apply under conditions of extreme heat or drought stress. A two ounce can treats up to 3,000 ft 2. UN Biological Grandevo 4 Contact biological stomach poison for armored scale only. Target newly hatched crawlers. Thorough coverage is important. Apply to non-blooming plants. See label if mixing with other pesticides. For greenhouse herbs/vegetables. Cyanoaniliprole 28 Diamide Mainspring 4 Contact and systemic activity. Foliar or soil application. Do not apply this product or allow it to drift to blooming plants or weeds if bees are foraging. Cyfluthrin 3A Pyrethroid Decathlon 20WP 12 Do not apply through irrigation systems. Spreader-sticker may help with hard to wet leaf surfaces. Good coverage is necessary. Dinotefuran 4A Neonicotinoid Safari 2 G 12 Contact and systemic. Use after flowering ends, pollen and nectar are not present. Toxic to bees. Make no more than 2 foliar or broadcast and/or 1 soil application per crop per year. Only drench moist substrate. Do not make foliar spray after soil drench.

189 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Fenoxycarb 7B Fenoxycarbs Prescription Treatment Preclude TR 180 Reentry Comments Interval (hours) 12 IGR. Micro-total release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days. Flonicamid 9C Flonicamid Aria (WSP) 12 Water-soluble packets. Insects stop feeding quickly but may remain on plants for up to 5 days. Product has residual control. Do not apply this product more than 2 times consecutively before rotating. Certain pansy cultivars have exhibited sensitivity to product. Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2F* T&O Bounty Discus Tablets 12 Systemic. For armored scale suppression only. Protection period is reduced if substrate has >30 50 % bark content. Do not apply to waterlogged or saturated soils. Do not apply while bees are foraging. Do not apply to plants that are flowering (only apply after all flower petals have fallen off). See label for rates/restrictions based on container size and application type. Labeled for armored (suppression) and soft scales. For armored and soft scale. Tablets are formulated to provide consistent delivery of active ingredient over time. Release of active ingredient is dependent on presence of adequate soil moisture.

190 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Class Trade Name (Formulation) 4A Neonicotinoid Imidacloprid 2F Select Lada 2F Lada 75 WSP Mallet 2F T&O Mallet 75 WSP Mantra 1 G Mantra 2F Mantra 60 WSP Marathon 1% G Marathon II (F) 181 Reentry Comments Interval (hours) 12 For greenhouse herbs only (7 day PHI). Do not apply through any irrigation system. Do not foliar apply following soil treatment. For armored and soft scale. Can incorporate into substrate before planting. Caution on ferns, Crassula, petunias, and lantana. For soft and armored (suppression; soil application only) scale. Systemic; to suppress armored scale (soil application only) and soft scale. Do not use more than once every 16 weeks. For armored and soft scale. Soil treatment only. Do not make more than 5 applications per year. Systemic; to suppress armored scale (soil application only) and soft scale. Do not apply through any irrigation system. Do not apply until roots are well established. Systemic insecticide to suppress armored scale (suppression; soil application only) and soft scale. Do not apply through any irrigation system. For soft scale. See AmTide. For armored and soft scales. Apply to well established root systems. For armored and soft scales. Can apply before egg-laying activity.

191 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Imidacloprid Cyfluthrin 4A 3A Class Insecticidal soap NC Potassium salts of fatty acids Kinoprene 7A Juvenile hormone analogues Trade Name (Formulation) Reentry Interval (hours) Comments Discus N/G 12 Contact & systemic insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Treat flowering plants when pollinating insects are not present. See label for application types, rates, and details. Insecticidal Soap (Bayer, Bonide, Earth-Tone, Natural Guard, Safer) DES-X M-Pede 12 Kills by contact so complete coverage is essential. Caution on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings for phytotoxicity (see label for others). Do not use on new transplants, unrooted cuttings, or plants stressed by drought or heat (>90 F). Apply early in morning or evening or when overcast; do not spray during full sun. Do not apply more than once per day. Do not spray open blooms or partially open flower buds. See label for details on plant safety and tank mixing.. Enstar AQ 4 IGR; see label for application information. Thorough coverage is necessary. Some varieties of roses show delayed damage. 182

192 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Lambda-cyhalothrin Class Trade Name (Formulation) Reentry Interval (hours) Comments 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact insecticide. Thorough coverage of all plant parts is important; a spreader-sticker is recommended. Do not apply through any type of irrigation system. Do not mix with EC formulations or oils. Neem oil NC Botanical Triact 70 4 Apply before insects or eggs are present in large numbers. Do not apply to wilted or stressed plants or new transplants before root establishment. Caution if applying to hibiscus flowers. Do not spray on impatiens flowers or cut roses. Do not make more than 5 applications per year and do not reapply more than once every 7 days. Product is also a fungicide - see label. 70% Neem Oil See above. Do not exceed 1 % rate in the greenhouse. Oil of rosemary and peppermint NC Botanical Ecotec 4 Contact insecticide for soft scale crawlers. Thorough coverage is important. Repeat every 5-7 days. Do not use if temperatures are >90 F. 183

193 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Oil, Horticultural (paraffinic hydrocarbon oils; petroleum oil, soybean oil, vegetable oil) Class Trade Name (Formulation) NC Oil Bonide All Seasons Horticultural Spray Oil (mineral oil) Golden Pest Spray Oil (soybean oil) JMS Stylet Oil # (paraffinic/mineral oil) Lesco Horticultural Oil (mineral oil) Monterey Horticultural Oil (mineral oil) PureSpray Green (petroleum oil) RTSA Horticultural oil + (mineral oil) SuffOil-X (paraffinic oil) SunSpray Ultra-fine Spray Oil (paraffinic oil) TriTek (mineral oil) Reentry Comments Interval (hours) 4 Complete coverage needed. Suffocates crawlers, eggs; suppresses adults. Do not apply to stressed plants or during prolonged periods of high temperatures and high relative humidity. Avoid using in greenhouses when overcast. Do not exceed label rates or apply more often than recommended. Effectiveness reduced at temperatures below 50 F. Do not apply through any irrigation system. See label if using with/before/after certain products and for use restrictions and mixing cautions. # Only labeled for mums. poinsettias, dieffenbachia, & philodendron. + For armored scale. Pyriproxyfen 7C Pyriproxyfen Distance (F) 12 IGR. Apply no more than twice per crop cycle or per 6 months. Do not apply to Boston fern, coral bells, ghost plant, salvia, gardenia, schefflera or poinsettias in bract. Pyrethrins 3A Pyrethrin Pyganic Crop Protection 12 Buffer final spray mix to ph In greenhouses, do not exceed maximum rates-see label. Do not apply more than once per day. Herbs are on label. 184

194 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Pyrethrin + Piperonyl Butoxide (PBO) Class Trade Name (Formulation) 185 Reentry Interval (hours) Comments 3A Pyrethrum TR 12 Total release aerosol formulation. Available in 2 oz container that treats up to 3,000 ft 2. Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for armored scales only. Suppresses immatures only. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettias after bract formation; see label for more. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. See label for complete list, rates, and specific instructions. Spirotetramat 23 Sulfoximine Kontos 24 Contact, stomach poison, systemic and translaminar insecticide for both knockdown control and up to one month of residual control. Not a neonicotinoid. Do not apply to edible crops or geranium. Treat prior to establishment of high pest populations and reapply as needed. See label for application types and plant safety information. #See label for drench REI. Sulfoxaflor (IsatoxR) Spinetorum 4C 5 Sulfoximine XXpire WG 12 See label for allowable crops; not for edible crops. Not a neonicotinoid. Has systemic and translaminar activity. Provides knockdown and up to one month of residual control. Do not apply more than 2 consecutive times or more than 4 times per year.

195 Table 11.9 Insecticides for Scale Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Thiamethoxam 4A Neonicotinoid Flagship 25 WG 12 For suppression of soft scales. Apply to foliage or soil or growing media. Product applied to foliage is rapidly absorbed/ distributed for rapid control of foliar feeding insects. Product applied to soil will be taken up by plant roots to pest feeding sites. Tolfenpyrad 21A METIinsecticides Hachi-Hachi 12 Contact insecticide. For use on non-food crops. Phytotoxic to blooms and some plants. Refer to label for more information. See label for rates for cut flowers. Allow at least 10 days between applications. Do not apply to gypsophilia, impatiens, salvia, or poinsettias in bract. No more than 2 applications per crop cycle or 4 applications/year See label for other crop tolerances. 186

196 Shore Fly Control Identification and Damage: Shore flies (Scatella tenuicosta) feed on algae and are found in areas where algae is growing such as under benches or on shaded, wet substrate. Adult shore flies are small, dark-gray flies (approximately 1/8 in. long) that slightly resemble a Drosophila fruit fly, with a robust body and short legs and antennae. They have five distinctive whitish spots on their grey wings. Their single pair of wings lacks the characteristic Y-shaped vein at the tip seen on fungus gnats. In addition, the shore fly adult has short antennae, unlike the long multi-segmented antennae of fungus gnat adults. Larvae of the shore fly are small translucent-white maggots without a distinct head capsule as seen in fungus gnat larvae. Larvae and adults are found in close association with algae. Larvae develop through 3 instars while feeding on the algae. Adult shore flies are considered a nuisance pest by greenhouse workers and consumers. In heavy infestations they also deposit characteristic unsightly black fly specks on foliage. Larvae are considered algae feeders and do not feed on crop plant tissue. Adult shore flies are capable of transmitting Pythium/damping off disease. Monitoring: Yellow sticky traps or tape are useful in monitoring adults as well as for mass trapping. Look for fly specks on foliage. Look for pupae that attach themselves (often in groups) to the sides of pots or objects just above the water level. Pay close attention to misted propagation facilities where algal growth and shore flies are common. Treatment: Reducing algae in the greenhouse on pots, floors, walls, and potting mix surfaces is the best way to reduce the populations of these pests. Avoid overwatering. 187

197 Table Insecticides for Shore Fly Control Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Azadirachtin 18B Botanical Aza-Direct 4 IGR. Controls by Azadirachtin & Pyrethrins AzaGuard Azamax (=NeemAzal) Molt-X Ornazin 3% EC 12 contact or ingestion as a repellent, antifeedant, and interference with the molting process. For use as a drench. May repel adults. Can use as a drench or as a foliar spray. Will break down in spray solution if ph >7.0 and/or not used within 8 hrs. Use promptly after mixing. Azatin XL 4 Soil drench for controlling soil-borne larvae - apply to moderately moist soils. See above. Azatrol See Aza-Direct; for larvae only. May reduce waxy bloom on ornamental plants. 3A Pyrethroid Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Kills by interfering with the molting process and as an adulticide. Effective on all insect life stages. Do not apply >1 time/ day or >10 times per season. Chlorpyrifos 1B Organophosphate DuraGuard ME 24 Microencapsulated formulation. Can apply as a foliar spray and as a coarse spray to soil surface. Caution on poinsettias, camellias, roses, and variegated ivies. Do not use on kalanchoes. Treating open blooms may cause petal drop. 188

198 Table Insecticides for Shore Fly Control (continued) Chemical Name IRAC Code Chlorpyrifos and Cyfluthrin 1B 3A Class Organophosphate Pyrethroid Trade Name (Formulation) Re-entry Interval (hours) Comments Duraplex TR (WP) 24 For wholesalers only. Micro Total Release spray; contact action. Apply when foliage is dry during early evening when temperature is between F. Do not apply through any irrigation system. Do not apply under conditions of extreme heat or drought stress. A 2 oz container; treats up to 3,000 ft 2. See label for specific instructions. Cyromazine 17 Cyromazine Citation (WSP) 12 IGR for control larvae; will not kill adult insects. Available in water soluble packets. See label use in low volume systems. Mandatory rotation details on label. Do not make more than a total of 6 applications to a single crop. Diflubenzuron 15 Benzoylureas Adept (WSP) 12 IGR; water soluble bags. Disrupts normal molting processes of insect larvae. Apply as soil drench or coarse spray to soil surface. For control of certain foliar-feeding insects, apply as foliar spray. Do not apply to poinsettias, hibiscus, or Rieger begonia. Do not apply to pots on capillary mats. Do not reuse treated potting substrate. See label for specific instructions. 189

199 Table Insecticides for Shore Fly Control (continued) Chemical Name IRAC Code Insecticidal Soap Metarhizium anisopliae strain F52 Nematodes, beneficial or entomopathogenic (Steinernema carpocapsae) Oil of rosemary and peppermint NC Class Potassium salts of fatty acids Trade Name (Formulation) 190 Re-entry Interval (hours) Comments M-Pede 12 Contact; short residual activity. Caution on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings (see label for others). Do not use on new transplants, unrooted cuttings, or drought or heat stressed plants (> 90 F). Apply early in morning or evening or when overcast; do not spray in full sun. Do not apply more than once per day. Do not spray open blooms or partially open flower buds. See label for tank mixing. N/C Biological Met 52 Exempt Bioinsecticide for larvae. Can use as foliar application or drench. Apply to moist substrate and keep moist. Biological Millenium (Steinernema carpocapsae) ScanMask (Steinernema feltiae) Exempt For larvae only. Insectparasitic nematode seeks out larvae, enters natural body openings, and releases symbiotic bacteria that kill the pests. Preventive or curative control. Apply to moist substrate right after potting. Continuous agitation is essential. Works best at 50 to 85 F. See label for tank mixing. NC Botanical Ecotec 4 Contact insecticide; labeled for herbs and vegetables. Use an adjuvant. Thorough coverage is important. Repeat application every 5-7 days. Do not use if temperatures are >90 F.

200 Table Insecticides for Shore Fly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 191 Re-entry Interval (hours) Comments Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR; controls immatures. Do not use low volume application equipment to control soil-inhabiting insects; use as a sprench. Treat under benches or where insects breed. Ensure complete coverage. Apply no more than twice per cropping cycle or not >2 times in 6 months. Do not apply to poinsettias in bract; see label for other damage potential. Do not apply to salvias, ghost plant, Boston fern, gardenia or coral bells. Spinosad 5 Spinosyn Conserve SC 4 Contact and stomach poison; thorough coverage of both upper and lower leaf surfaces is important. Do not apply to edible crops. See label for application types and use and rate restrictions. See label for resistance management. Entrust See above. Do not apply >6 times in a 12-month period. Never make more than 3 consecutive applications. Can use on herbs and vegetable transplants. Toxic to bees. Sulfoxaflor (IsatoxR) Spinetorum 4C 5 Sulfoximine XXpire WG 12 See label for crop list. Not a neonicotinoid. Has systemic and translaminar activity. Provides knockdown and up to one month of residual control. Do not make more than 2 consecutive applications. Do not make > 4 applications per year.

201 Slug Control Identification and Damage: Slugs are soft bodied arthropods with beak like mouthparts. Garden slugs, pear slugs and brown slugs are three common species found in the greenhouse. High moisture levels in the greenhouse create ideal conditions. The slugs lay eggs in cryptic spots. Slugs live for several years, depending on species and can build up over several years in a greenhouse. Foliage is torn and shredded from slug feeding. Slime trails are often found on foliage. Monitoring: Look for slime trails on plants. Examine foliage for torn or shredded damage. Slugs hide during sunny weather and during the day. Since slugs are active in overcast weather and at night, monitoring should occur during these times. Rotting wooden benches are favored by slugs and should be inspected. Treatment: Inspect incoming plants and containers for the presence of slugs. Remove weeds and slug hiding places (debris, boards, empty containers, etc.) in and around the greenhouse. Research shows that fewer slug problems exist in greenhouses where plants are grown on expanded metal benches vs. wooden benches or on the ground. Handpicking slugs can be helpful in small infestations and is best done in the early evening (~two hours after sunset). Copper flashing/strips can act as a slug barrier; wrap copper tape on bench legs or surround raised beds with flashing to help exclude slugs. Abrasive materials such as dry gravel or diatomaceous earth may also act as a barrier that slugs may not cross, as long as these materials remain dry. Poison baits must be eaten by slugs. Apply baits in the evening irrigating prior to placement -- when slugs are active. 192

202 Table Pesticides for Slug Control Chemical Name IRAC Code Class Trade Name (Formulation) Re-entry Interval (hours) Comments Iron phosphate NC Inorganic Bonide Slug Magic 0 RTU bait pellets Iron phosphate + Spinosad NC 5 Inorganic Spinosyn Earth Tone Slug and Snail Control Escar-Go Slug and Snail Bait Garden Safe Slug and Snail Bait Ortho EcoSense Slug and Snail Killer Sluggo-AG Snail & Slug Killer Bait Worry Free Lilly Miller Slug & Snail Bait (granules). Apply in evening when soil is moist but not saturated. Reapply as bait is consumed or every two weeks as needed. Do not place in piles. For terrestrial use only. See label for complete plant list, rates, and specific instructions. Sluggo Plus 0 See above. Do not make applications less than 7 days apart. See label for application rates and details. Bonide Bug & Slug Killer None See above. Wet soil before application. Do not apply >3 times/month. Best to apply in the evening. See label. Bug-N-Sluggo 4 Highly compressed pellets (shorts). Do not apply >3 times/month. See label. 193

203 Table Pesticides for Slug Control (continued) Chemical Name IRAC Code Class Metaldehyde NC Aldehyde molluscicide Trade Name (Formulation) 194 Re-entry Interval (hours) Comments Deadline Bullets 12 Bait granules/pellets. Soil treatment. Apply in early evening preferably after watering. Do not water for 48 hrs. Do not apply directly to plants. Maximum of 6 treatments per year. Deadline M-Ps Mini-pellets. Most plants show tolerance to product; caution on tender plants such as orchids. Hi-Yield Improved Slug & Snail Bait Metarex 4% Slug & Snail Bait Mesurol 75 WP Mesurol Pro Durham Metaldehyde Granules 3.5 Durham Metaldehyde Granules 7.5 Natural plant oil attractants are added to each mini pellet. Do not apply to dry soil. Do not treat dry soil. Do not water again for 48 hrs. Maximum of 6 applications/year. Restricted use. Do not apply with foliar fertilizers or oils. Do not use >2 times per year. Spray solution ph should be >7. Apply at least 10 days apart. Restricted use. Do not use on plants grown for food. Irrigate before broadcasting bait over foliage or treating soil around plants, under benches or around building foundations. Do not use more than twice per year. Water thoroughly before treatment. Do not water again for 48 hrs. Do not apply to plants unless known tolerance.

204 Table Pesticides for Slug Control (continued) Chemical Name IRAC Code Sodium ferric EDTA Sulfur Class Trade Name (Formulation) Re-entry Interval (hours) Comments Iron Fist 0 Do not apply to water or to areas around surface water or intertidal areas. Do not apply bait to softleaved plants. See label directions. Ortho Bug-Geta Slug and Snail Killer 2 Unique blend of sulfur with slug and snail bait additives. Will degrade and return sulfur and calcium to the soil. Slugs/ snails cease feeding after ingestion; become less mobile and die within 1-3 days. See specific directions for different plant types and for inside greenhouses. 195

205 Thrips Control Identification and Damage: Adult thrips are small, about 1/16-inch - 1/32 inch long, with long, narrow bodies and fringed wings. Females are reddish brown and males are light tan to yellow. Most adult thrips seen in a greenhouse are females; reproduction without fertilization is common. Adults are gregarious, large numbers are found feeding in protected areas of the plant such as flowers and terminals. Eggs are inserted into leaf or petal tissue and are thus protected from insecticides. The two wingless larval stages vary in color from light yellow to orange to green. The larvae usually remain protected in flower buds or foliage terminals. While in two pupal stages in the soil, they are protected from insecticides directed at the crop. Currently, no pesticides are labeled as drenches to kill thrips pupae in soil. The pest s rapid developmental time (egg to adult in 7 to 15 days under fluctuating temperatures), high reproductive rate, and preference for protected areas can make early detection difficult. Adults fly readily and can be carried by wind currents or on clothing to greenhouses near an infested field. They can fly from a sprayed to an unsprayed area or move into or out of a greenhouse through doors or greenhouse vents. Some species of thrips such as the western flower thrips (WFT) vector tospoviruses. Feeding marks from the rasping mouthparts of thrips destroy plant cells and appear as silvery-white streaks on the leaves or flowers. Infested new growth may curl under, and leaves are often deformed. Monitoring: Early detection of a thrips infestation is critical because the symptoms of thrips feeding are often not noticed until after damage or virus transmission has occurred and because an infestation is easier to control when it is small. When the crop is in flower, detect thrips using a white or yellow piece of paper placed under open flowers. Gently tap the flowers and use a 10x magnifier to examine the insects that fall out. Using yellow or blue sticky cards is the easiest way to detect the onset of an infestation. To monitor the movement of thrips, place the cards just above the crop canopy, at about one per 500 square feet, as well as near doors, vents, and over thrips-sensitive cultivars. Recent research shows that light- to medium-blue sticky cards catch more thrips than yellow ones. To monitor only for adult thrips, use the blue sticky cards. Keep a weekly record of the number of thrips per card and graph the totals to detect trends. This information will help with population estimates and in correctly timing pesticide applications. Treatment: Remove any weeds and plant debris in and around the greenhouse that may harbor thrips. Locate all trash containers away from the growing area. Screen any building openings (vents, walls with cooling pads) to prevent or exclude thrips from entering the greenhouse. Sprays must thoroughly cover plants, including flowers. Small spray droplets are recommended in order to penetrate flower buds. Mixing a pyrethroid irritant into the spray mix can compel thrips to leave their hiding places for better spray exposure. Rotate all sprays in order to minimize resistance. If releasing beneficial natural enemies, do so prior to damaging pest population levels. 196

206 Table Insecticides for Thrips Control Chemical Name IRAC Code Class Trade Name (Formulation) 197 Reentry Interval (hours) Comments Abamectin 6 Avermectin Ardent 0.15 EC 12 Suppression. Foliar contact spray; with translami- Avid 0.15 EC nar properties.thorough Lucid 2F coverage is important. Do Merlin (Phoenix not apply through any irrigation system. Caution on Merlin) Minx roses, chrysanthemums, and gerbera. Do not use on ferns or Shasta daisies. Avoid contact and breathing spray mist. Acephate 1B Organophosphate 1300 orthene TR 24 Total release cans. Best to apply in early evening when foliage is dry and greenhouse temperatures are F. Ventilate greenhouse before reentry. Acephate 90 Contact insecticide. Do not treat poinsettias in bract or roses and chrysanthemums in bloom. Acephate 97 Up Systemic with ingestion action. Only labeled in greenhouse for anthurium, cacti, carnations chrysanthemums, foliage plants, orchids, roses, and poinsettias. Do not apply through irrigation system. Do not treat freshly rooted cuttings, poinsettias in bract or roses or chrysanthemum in flower. Toxic to bees & birds. Orthene TT&O 97 Systemic. Do not apply to freshly rooted cuttings. Limited crop use. Not for cut flowers. Do not use a low pressure hand wand. Do not apply to poinsettias in bract or to roses or chrysanthemums in flower.

207 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 198 Reentry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 30 SG 12 Contact insecticide with translaminar activity. Thorough coverage is important. A surfactant may improve efficacy. Do not overhead irrigate for 6 hrs after application. Do not make more than 4 applications per year and do not reapply more than once every 7 days. TriStar 8.5 SL Water-soluble bags applied as a foliar spray. Do not make more than 5 applications per year and do not reapply more than once every 7 days. See label for plant list, rates, and specific instructions. Toxic to bees.. Azadirachtin 18B Botanical Aza-Direct 4 IGR. Controls by contact AzaGuard or ingestion as a repellent, antifeedant, and interference with the molting Azamax (=NeemAzal) process. For use as a Azatin-O drench or as a foliar spray. Molt-X May repel adults. Can be used as a drench or as a foliar spray. Will break down in the spray solution if ph >7.0 and/or not used within 8 hrs. Use promptly after mixing. AzaSol May be applied to any food crop. High water solubility; thorough coverage is needed. Azatin XL EC See Aza-Direct above. Apply to moderately moist soils. Ecozin Plus 1.2% ME Only for herbs and vegetables in greenhouse. Ornazin 3% EC 12 See Aza-Direct. See label.

208 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Azadirachtin & Pyrethrins Beauveria bassiana GHA stain Bifenazate + abamectin Class Trade Name (Formulation) Reentry Interval (hours) Comments 3A Pyrethroid Azera 12 For greenhouse thrips only; contact or ingestion. Quick knockdown. Can use on herbs. Kills by interfering with the molting process and as an adulticide. Effective on all insect life stages. Do not apply when windy. Do not apply >1 time/ day or >10 times per season. NC Microbial Botanigard ES 4 Insect-killing fungus; Botanigard 22 WP Mycotrol O (WP) N/A Sirocco (=Prevamite O) kills on contact. Do not tank mix with fungicides. Thorough coverage is essential. Needs relative humidity greater than 70% and F for 8-10 hrs. Normally takes 3-7 days for insects to die and 7-10 days after first spray to see a reduction in an insect population. Product may be used as a preplant dip for cuttings. For soil applications do not apply to water-saturated soils. See label for plant list, rates, and specific instructions. Do not treat poinsettias in bract. 12 For suppression only. Contact and translaminar insecticide. For non-food crops. Thorough coverage of foliage is essential; young immatures must be contacted by the spray. Do not make >2 applications per crop per year. 199

209 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. For best results apply during early evening when foliage is dry and temperature is between F. Greenhouse should be ventilated before reentry. Do not reapply product within 48 hrs of a previous application. See label for plant list, rates, and specific instructions Menace GC 7.9% Flowable (F) Talstar P (Professional) (F) Talstar Select (FC) Contact insecticide. Thorough coverage of all plant parts is important. Do not apply through any irrigation system. Do not allow runoff to occur. Foliar application. Do not apply to food crops. Do not apply through any type of irrigation system. Spreader stickers are not necessary. Do not use on edible plants. Can be tank mixed with plant growth regulators. See label for details. UpStar SC Do not use more than 1 fl. oz. per 1000 ft 2. Foliar application. Do not use through any irrigation system. Wisdom F Thorough coverage is important. Do not apply through any irrigation system. 200

210 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Chlorfenapyr 13 Pyrrole Pylon 12 Contact; stomach poison with translaminar activity. For ornamentals and fruiting vegetables. Thorough coverage is needed. Do not apply >3 times within a season. Not ovicidal. Toxic to bees; apply prior to bloom. Phytotoxicity caution on carnations, dianthus, kalanchoe, poinsettias, roses, salvias and zinnias. See label for plant safety, details and application information (including use on plugs). Pylon TR See above. Total release product, available in 2 oz containers that treat up to 3,000 ft 2. Do not compost any discarded plant materials that have been treated with this product. See label for details, directions, and precautions. Chlorpyrifos 1B Organophosphate DuraGuard ME 24 Microencapsulated formulation. Caution on azaleas, poinsettias, camellias, roses, and variegated ivies. Do not use on kalanchoes. Direct treatment to some open blooms may cause petal drop. See label for plant list, specific rates, and instructions. 201

211 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Chlorpyrifos + Cyfluthrin( Chromobacterium subtsugae strain PRAA4-1 1B 3A Class Organophosphate Pyrethroid Trade Name (Formulation) Duraplex TR (=Descriptor Total Release Insecticide)) 202 Reentry Comments Interval (hours) 24 For wholesalers only. Micro Total Release spray; by contact. Apply to dry foliage in early evening when temperature is F. Do not apply through irrigation system. Do not apply when extreme heat or drought stress. A 2 oz container treats up to 3,000 ft 2. UN Biological Grandevo 4 Contact stomach poison. Target newly hatched nymphs. Thorough coverage is important. Apply to non-blooming plants. See label if tank mixing. Can use on greenhouse herbs and vegetables. Cyanoaniliprole 28 Diamide Mainspring 4 Both contact and systemic activity. Foliar or soil application. Do not apply this product or allow it to drift to blooming plants or weeds if bees are foraging. Cyfluthrin 3A Pyrethroid Decathlon 20 WP 12 Do not apply through any type of irrigation system. A spreader-sticker may enhance coverage of hard to wet leaf surfaces. Good coverage is necessary. Dinotefuran 4A Neonicotinoid Safari 2G 12 Contact; systemic. Apply after plants bloom and pollen and nectar are not present. Apply no more than 2 foliar or broadcast and/or 1 soil application per crop per year. Only drench moist substrates, not dry or saturated. Do not apply foliar sprays after plants receive a soil drench. Toxic to bees.

212 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Fenoxycarb 7B Fenoxycarbs Prescription Treatment Preclude TR Reentry Comments Interval (hours) 12 IGR. Micro encapsulated release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days. Flonicamid 9C Flonicamid Aria (WDG) 12 Water-soluble packets. Insects stop feeding quickly but may remain on plants for up to 5 days. Product has residual control. Do not apply more than 2 times consecutively before rotating. Certain pansy cultivars have exhibited sensitivity to product. Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2F* T&O Bounty Discus Tablets 12 For suppression only. Systemic. Protection period is reduced if substrate has >30 50 % bark content. Do not apply to substrate that is waterlogged or saturated. Do not apply while bees are foraging; apply after all flower petals have fallen off. See label for details and rates/restrictions based upon container size and application type. For suppression only. See above. Tablets are formulated to provide consistent delivery of active ingredient over time. Release of active ingredient is dependent on presence of adequate soil moisture. Follow label directions. 203

213 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Class Trade Name (Formulation) 4A Neonicotinoid Imidacloprid 2F Select Lada 2 F Lada 75 WSP Mallet 2F T&O Mallet 75 WSP Mantra 1 G Marathon 1% G Marathon II Reentry Comments Interval (hours) 12 Suppression only. See AmTide. For Greenhouse herbs only (7 day PHI). Do not apply through any irrigation system. Do not foliar apply following a soil application in the same crop. Thrips suppression on foliage only. Thrips in buds and flowers will not be suppressed. Can incorporate into substrate before planting. Caution on ferns, Crassula, petunias, and lantana. See label for application options, rates, and details. Systemic. Can incorporate into the substrate before planting. Do not apply to flowering plants. Caution on ferns, Crassula, petunias, and lantana. Suppression only. Not to be used more than once every 16 weeks. Suppression only. Soil treatment only. Do not make more than 5 applications per year. Suppression only. For crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. Suppression only. Beware of pollinator warnings when treating. Applications can be made before egg-laying activity of target pests. 204

214 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Imidacloprid Cyfluthrin 4A 3A Class Insecticidal soap NC Potassium salts of fatty acids Trade Name (Formulation) Reentry Interval (hours) Comments Neonicotinoid Discus N/G 12 Contact & systemic insecticide for foliar or soil applications. Protection period is reduced if substrate has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Make applications to flowering plants when pollinating insects are not present. Insecticidal Soap (Bayer, Bonide, Earth-Tone, Natural Guard, Safer) DES-X M-Pede 12 Kills by contact so complete coverage is essential. Caution on Euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings for phytotoxicity (see label for others). Do not use on new transplants, unrooted cuttings, or plants stressed by drought or heat (>90 F). Apply early in morning or evening or when overcast; do not spray during full sun. Do not apply more than 1 time per day. Do not spray open blooms or partially open flower buds. See label for information on tank mixing.. See above; only labeled for blossom thrips on African violets. 205

215 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) Class Trade Name (Formulation) 206 Reentry Interval (hours) Comments NC Biological NoFly WP 12 Contains live spores of an insect-killing fungus. For non-food crops. Foliar application. Works best at temperatures between F with high humidity. Typically takes 3-7 days for insects to die. Avoid breathing spray mist. May cause moderate eye irritation. Do not apply when bees are foraging. Preferal See above. Most effective when use begins at first appearance of pests before high populations develop. Frequent scouting is critical to success. Kinoprene 7A Juvenile hormone analogues Lambda-cyhalothrin Metarhizium anisopliae strain F52 Enstar AQ 4 IGR. Thorough coverage is necessary. Some varieties of roses show delayed damage. 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact insecticide. Thorough coverage is important; a spreadersticker is recommended. Do not apply through any irrigation system. Do not mix with EC formulations or oils. N/A Biological Met For western flower thrips only. Can be used as foliar application or drench. Do not apply to poinsettias after bract formation. Apply to moist substrate and keep moist.. Met 52 G See above. For thrips pupae only. Thoroughly mix product into growing substrate, ensuring even distribution

216 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 207 Reentry Interval (hours) Comments Methiocarb 1A Carbamate Mesurol 75WP 24 For western flower thrips. Contact insecticide. Do not apply with foliar fertilizers. Effectiveness may be reduced when the spray solution ph >7. Do not apply more than 2 times per year per crop or less than 10 days apart. Neem Oil NC Clarified hydrophobic extract of neem oil Nematodes, beneficial or entomopathogenic NC Biological Entonem (Steinernema feltiae) NemaShield (Heterohabditis bacterophora) Nemasys (Steinernema feltiae) Triact 70 4 Apply before insects are present in large numbers. Do not apply to stressed plants or new transplants prior to root establishment. Caution if applying to hibiscus flowers. Do not treat impatiens flowers or cut roses. Do not apply more than 5 times per year or less than 7 days apart. 70% Neem Oil See above. Do not exceed 1.0% rate in the greenhouse. 0 Insect-parasitic nematode seeks out western flower thrips adults and pupae. Preventive or curative suppression. Apply to moist substrate after potting as a drench or through drip irrigation system (remove filters). Do not exceed 300 psi pump pressure. Apply in evening or on cloudy days due to extreme UV light sensitivity. Repeat applications are usually needed. Substrate temperatures must be F. Irrigate before and after application. See label for tank mixing cautions.

217 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 208 Reentry Interval (hours) Comments Novaluron 15 Benzoylurea Pedestal 12 IGR; controls immatures (not adults). Do not use more than once within each generation cycle. Do not make more than 2 applications per crop per year. Do not apply to poinsettias. See label for complete plant list, rates, and specific instructions. Oil of Rosemary and Peppermint Oil, Horticultural (paraffinic hydrocarbon oils; petroleum oil, soybean oil, vegetable oil) NC Botanical Ecotec 4 Contact insecticide; thorough coverage of all plant parts is important. Repeat application every 5-7 days. Do not use if temps are >90 F. NC Oil Golden Pest Spray Oil (soybean oil) PureSpray Green (petroleum oil) SuffOil-X (paraffinic oil) Summit Year Round Superior Horticulture Spray Oil (mineral oil) SunSpray Ultra-fine Spray Oil (paraffinic oil) TriTek (mineral oil) Ultra-Pure Oil (Petroleum oil) 4 Suffocates eggs, nymphs and adults; complete coverage needed. Do not apply to stressed plants or during periods of prolonged high temperatures and high relative humidity. Avoid spraying in greenhouses under overcast conditions. Effectiveness is reduced at temperatures below 50 F. Do not apply through irrigation system. See label for cautions if using with/before/following application of certain products and for use restrictions, and mixing. Permethrin 3 Pyrethroid Astro 12 Contact insecticide for citrus Permethrin 3.2 AG thrips only. Thorough coverage is important. Direct application to blooms may cause browning of petals. Marginal leaf burn may occur on salvia, dieffenbachia, and Pteris fern.

218 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Pyrethrins 3A Pyrethrin Pyganic Crop Protection Pyrethrins Piperonyl butoxide 3A 27A Pyrethrin Pyrenone 5.0 Crop Spray (EC) Pyronyl Crop Spray (Prentox) Pyrethrum TR 209 Reentry Interval (hours) Comments 12 Herbs listed on label. Buffer spray mix to a ph of In greenhouse, do not exceed maximum rate of.0036 Ibs a.i./1,000 ft 2 or 1.18fl. oz./1,000 ft Includes a synergist to flush insects out of hiding into contact with spray residues. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can tank mix with other insecticides. See above. No more than 10 applications/season in greenhouse. Total release aerosol. 2 oz can treats up to 3,000 ft 2. Pyridalyl NC Pyridalyl Overture 35WP 12 Contact, ingestion and translaminar activity. Do not apply >3 times per cropping cycle. Can use high volume sprayers or low volume applicators including PulseFOG or Electrostatic Spraying Systems. Do not apply through irrigation system. Pyrifluquinazon UN Rycar 12 Contact and translaminar insecticide for chilli thrips only on non-food crops. Causes immediate stopfeed. Thorough spray coverage needed. Do not apply through irrigation system. Do not harvest cut flowers for 48 hrs. Do not compost treated plant material. Do not allow spray to run off outside of area. Do not apply >2 times per crop cycle.

219 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 210 Reentry Interval (hours) Comments Spinosad 5 Spinosyn Conserve SC 4 Contact and stomach poison; thorough coverage of both upper and lower leaf surfaces is important. Do not apply to edible crops. See label for application type, use and application rate restrictions. Can be used on aquatic plants in commercial pools only. See label for resistance management. Entrust For exposed Cuban laurel and western flower thrips only. Thorough coverage of both upper and lower leaf surfaces is critical. Do not apply >6 times in a 12-month period. Never apply more than 3 consecutive applications. Can apply to herbs and vegetable transplants. Toxic to bees. Spirotetramat 23 Sulfoximine Kontos 12 Contact, stomach poison, systemic and translaminar insecticide for knockdown and residual control of immature thrips. Not a neonicotinoid. Provides knockdown and up to one month of residual control. Do not apply to edible crops. Start treatments prior to establishment of high pest populations and reapply on an as-needed basis. See label for drench REI. See label for list of plants, application types, and important plant safety information.

220 Table Insecticides for Thrips Control (continued) Chemical Name IRAC Code Sulfoxaflor (IsatoxR) Spinetorum 4C 5 Class Trade Name (Formulation) 211 Reentry Interval (hours) Comments Sulfoximine XXpire WG 12 See label for crops allowed. Has contact, systemic and translaminar activity. Do not treat edible crops. Not a neonicotinoid. Provides knockdown and up to one month of residual control. Do not make more than 2 consecutive applications. Do not make more than 4 applications per year. Tau-fluvalinate 3A Pyrethroid Mavrik Aquaflow 12 Buffer spray to ph 5-7. Do not apply more than 4 sprays per month. May work slowly on some species. Allow 3 4 days to evaluate performance. Caution on roses and poinsettias. Can use as a dip for flower and foliage cuttings. May cause respiratory allergic response. Thiamethoxam 4A Neonicotinoid Flagship 25 WDG 12 Product applied to foliage is rapidly absorbed/distributed for rapid control of foliar feeding insects. Product readily taken up by plant roots to pest feeding sites. See label for application directions. Tolfenpyrad 21A METIinsecticides Hachi-Hachi 12 Contact insecticide. For use on non-food crops. Phytotoxic to blooms and some plants; refer to label. Allow at least 10 days between applications. Do not apply to gypsophila, impatiens, salvia, or poinsettias in bract. Apply no more than twice per crop cycle or 4 times/year

221 Whitefly Control Identification and Damage: Whiteflies are small flying insects (0.06 in. or 1-2 mm) that feed on many greenhouse crops, particularly poinsettias and bedding plants. Both the adults and immature stages are found on the underside of the leaves where they suck plant fluids. Adults of greenhouse whitefly (Trialeurodes vaporariorum) have powdery-white wings that are held flat over their bodies. Bemesia tabaci whitefly adults are slightly smaller than the greenhouse whitefly adults and yellowish in color. They hold their wings roof-like, at a 45-degree angle close to their body. The adult bandedwinged (Trialeurodes abutilonea) have two grayish bands that form a zigzag pattern across each front wing. Eggs are white when first laid and turn dark grey (greenhouse whitefly) or amber brown (B. tabaci whitefly) with time. The insect hatches from the egg as a crawler, which is an active, mobile stage and moves about on the plant looking for a feeding site on which to settle. The crawler and other nymphal stages of the most common species are oval, greatly flattened, and somewhat translucent with a white, lightgreen or light-yellow cast. On floricultural crops, even a few whiteflies can reduce the retail value for several reasons. Flying adults can result in consumer complaints. High populations of whiteflies can weaken plants, causing chlorotic foliage and reduced vigor. Whiteflies are phloem feeders and can weaken plants by directly consuming carbohydrates and other nutrients carried within a plant s vascular system. Heavy populations can cause defoliation. Whiteflies also produce honeydew excretions, which cause leaves to become sticky and shiny, as well as the resulting sooty mold fungus. Furthermore, Bemesia tabaci (B strain or Q strain) can cause tomato fruit to become mottled (uneven ripening), the leaves of squash to turn silver green, and hibiscus foliage to have yellow speckles. In severe infestations, the insect can cause stems and bracts of red poinsettia cultivars to turn whitish yellow. B. tabaci whiteflies are found to be capable of transmitting plant viruses. Monitoring: Sampling for whiteflies is critical to establishing whether a treatment threshold has been reached and to determining whether a treatment is effective. Use a combination of yellow sticky traps and foliage inspection. Monitor the location and relative numbers of adults with yellow sticky traps; nymphs must be monitored by frequent foliage inspection. Observe adult activity on foliage to become aware of egg laying and potential population build-up on hotspot plants in a greenhouse. The older life stages are often found on older foliage; eggs and younger life stages are usually found on younger leaves. Sticky cards are best used at 1 to 2 cards per 1,000 square feet of growing area; check the cards weekly at a minimum. The threshold of adults found on a card per day and numbers of nymphs per leaf often changes according to the maturity of the crop. Early in a crop cycle a grower may tolerate 0.5 whitefly per day on cards. At the time near the sale of the crop the grower may have an increased tolerance of adults, allowing 2 whiteflies per card per day. Treatment: Proper species identification is important in order to choose the most effective management option. Insecticides are applied as either foliar sprays (targeting nymphs and adults), systemic drenches (targeting nymphs), or smoke fumigation (targeting adults). Rotate all sprays in order to minimize resistance. If releasing beneficial natural enemies, do so prior to damaging pest population levels. 212

222 Table Insecticides for Whitefly Control Chemical Name IRAC Code Class Trade Name (Formulation) Abamectin 6 Avermectin Abamectin SPC 0.15 EC Ardent 0.15 EC Avid 0.15 EC Merlin (Phoenix Merlin) Lucid Minx 213 Reentry Comments Interval (hours) 12 Foliar contact spray; translaminar properties. Suppression. Thorough coverage is important. Do not apply through any irrigation system. Caution on roses, chrysanthemums, and gerberas. Do not use on ferns or Shasta daisies. Avoid contact and breathing spray mist. Acephate 1B Organophosphate 1300 Orthene TR 24 Total release cans. Best to apply in early evening when foliage is dry and greenhouse temperatures are F. Ventilate greenhouse before reentry. Acephate 90 Contact insecticide. Do not treat poinsettias in bract or roses and chrysanthemums in flower. See label for phytotoxicity. Acephate 97 UP Systemic; ingestion action. Only labeled in greenhouse for cacti, anthurium, carnations chrysanthemums, foliage plants, orchids, roses, and poinsettias. Do not apply through irrigation system. Do not treat poinsettias in bract, roses or chrysanthemums in flower, or freshly rooted cuttings. Toxic to bees and birds. Acephate (continued) 1B Organophosphate Orthene TT&O 97 WP 24 Systemic. For use on limited crops. Do not apply with a low pressure hand wand. Do not apply to poinsettias in bract, roses or chrysanthemums in flower, cut flowers, or freshly rooted cuttings.

223 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 214 Reentry Interval (hours) Comments Acetamiprid 4A Neonicotinoid TriStar 30 SG 12 Contact insecticide with translaminar activity. Thorough coverage is important. A surfactant may improve efficacy. Do not overhead irrigate for 6 hrs after application. Do not make more than 4 applications per year or reapply more than once every 7 days. TriStar 8.5 SL Water-soluble bags used as a foliar spray. Make no more than 5 applications per year; do not reapply more than once every 7 days. Toxic to bees. Azadirachtin 18B Botanical Aza-Direct 4 IGR. Controls by AzaGuard Azamax (=NeemAzal) Bayer/Bonide Neem Oil Concentrate Azatin-O Bayer/Bonide Neem Oil Concentrate Molt-X AzaSol Azatrol Ecozin Plus 1.2% ME Neemix 4.5 (EC) contact or ingestion as a repellent, antifeedant, and interference with the molting process. For use as a drench or as a foliar spray. May repel adults. Will break down in the spray solution if ph >7.0 and/or not used within 8 hrs. Use promptly after mixing. Can use on any food crop. High water solubility; thorough coverage needed. May reduce waxy bloom on some plants. Only for herbs and vegetables in greenhouse. Only immature stages. Direct spray to pest, longer duration of leaf wetness increases efficacy. Do not treat stressed plants or before roots established. Ornazin 3% EC 12 See Aza-Direct.

224 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Azadirachtin & Pyrethrins( Beauveria bassiana GHA stain Bifenazate + abamectin Class Trade Name (Formulation) Reentry Interval (hours) Comments 3A Pyrethroid Azera 12 Works by contact or by ingestion. Quick knockdown. Can use on herbs. Adulticide. Interferes with molting process. Effective on all life stages. Do not apply >1 time/ day or >10 times per season. NC Microbial Botanigard ES 4 Insect-specific fungus. Do not tank mix with Botanigard 22 WP fungicides. Acts by contact; thorough coverage Mycotrol O (WP) is essential. Needs temperature of F and relative humidity >70% for 8-10 hrs. Takes 3-7 days for insects to die and 7-10 days after first spray to see reduction in pest population. Can use as a pre-plant dip for cuttings. For soil applications do not apply to water-saturated soils. Do not treat poinsettias in bract. Formulated for use without wetting agents and spreaders. N/A Sirocco (=Prevamite O) 12 Contact and translaminar. For suppression only. For non-food crops. Thorough coverage is essential; Spray must contact young immatures. Do not make >2 applications per crop per year. 215

225 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 216 Reentry Interval (hours) Comments Bifenthrin 3A Pyrethroid Attain TR 12 Micro Total Release cans. For best results apply during early evening when foliage is dry and temperature is F. Ventilate greenhouse before reentry. Do not reapply it within 48 hrs. Menace GC 7.9% F Contact insecticide. Thorough coverage is important. Do not apply through irrigation system. Do not treat to runoff. Talstar P (Professional) (F) Talstar Select (FC) Up-Star SC Wisdom F For adults. Thorough coverage is important. Foliar application. Do not apply to food crops. Do not apply through any irrigation system. Spreader stickers are not necessary. Can tank mix with plant growth regulators. Do not apply through irrigation system. See label for specifics. Buprofezin 16 Buprofezin Talus 70 DF 12 IGR for nymphs. Apply no more than twice per season. Do not apply through any irrigation system. Apply as soon as activity is observed. Chlorpyrifos + Cyfluthrin 1B 3A Organophosphate Pyrethroid Duraplex TR (=Descriptor Total Release Insecticide) 24 For wholesalers only. Micro Total Release; a 2 oz container treats up to 3,000 ft 2. Contact. Apply when foliage is dry in early evening when temperature is F. Do not apply through any irrigation system. Do not apply when extreme heat or drought stress.

226 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Chromobacterium subtsugae strain PRAA4-1 Class Trade Name (Formulation) Reentry Interval (hours) Comments UN Biological Grandevo 4 Contact biological stomach poison. Proper timing targeting newly hatched nymphs is important. Thorough coverage is important. Apply to non-blooming plants. See label warning if mixing with other pesticides. Can use on greenhouse herbs and vegetables. Cyanoaniliprole 28 Diamide Mainspring 4 Foliar or soil application; both contact and systemic activity. Do not apply this product or allow it to drift to blooming plants or weeds if bees are foraging. Cyfluthrin 3A Pyrethroid Decathlon 12 Do not apply through any type of irrigation system. A spreader-sticker may enhance coverage of hard to wet leaf surfaces. Good coverage is necessary. Dichlorvos 1B Organophosphate DDVP 20% EC * Only for greenhouse ornamentals, tomatoes and cucumbers. Spray until runoff; thoroughly ventilate before reentering the next day. Do not apply when foliage or blossoms are wet as injury may result. Some damage has been noted on Shasta and Pink Champagne Chrysanthemums and some varieties of snapdragons. See label precautions. * Meet WPS Ventilation requirements 217

227 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Diflubenzuron 15 Benzoylurea Adept (WSP) Dimilin SC (F) 12 IGR; water soluble bags. Disrupts normal molting processes of nymphs. Apply as soil drench or coarse spray to substrate surface. For control of certain foliar-feeding insects, apply as foliar spray. Do not apply to poinsettias, hibiscus, or Rieger begonia. Do treat pots on capillary mats. Do not reuse treated potting substrate. Dinotefuran 4A Neonicotinoid Safari 2G 12 Contact and systemic insecticide. Apply after plants finish blooming and pollen and nectar are no longer present. No more than 2 foliar or broadcast applications and/or 1 soil application may be made per crop per year. Only apply soil drench to moist soil substrate, dry or saturated. Do not apply foliar sprays to plants that have received a soil drench. Toxic to bees. Etoxazole 10B Beethove TR 24 Total release cans for suppression only; treats up to 3,000 ft 2. For ornamentals only. Contact and translaminar activity. Do not apply to plants under stress. Apply during early evening when foliage is dry and greenhouse temperatures are between F. See label for application details and specifics. 218

228 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) 219 Reentry Interval (hours) Comments Fenazaquin 21A METI-acaricides Magus 12 Kills by contact and ingestion. Thorough coverage is required. Do not use on roses. No more than one application per crop. Do not apply through any type of irrigation system. See label for information on plant safety. Fenoxycarb 7B Fenoxycarb Preclude TR 12 IGR; micro encapsulated release. Cans must be stored at >65 F for 24 hrs before release. Do not use more than every 7 days. See label for details. Flonicamid 9C Flonicamid Aria (WSP) 12 Spray water should be buffered to ph 5 7. Can be used as a dip for flower and foliage cuttings. Do not use through any type of irrigation system. Fenpyoximate 21 Akari 5 SC 12 For greenhouse ornamentals, tomatoes, cucumbers only. Spray water should be buffered to ph 5 7. Can be used as a dip for flower and foliage cuttings. Do not use through any irrigation system. See label for plant safety information. Flonicamid 9C Flonicamid Aria (WSP) 12 Water-soluble packets. Insects stop feeding quickly but may remain on plants for up to 5 days. Product has residual control. Do not apply this product more than 2 times consecutively before rotating. Certain pansy cultivars have exhibited sensitivity to product.

229 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Imidacloprid 4A Neonicotinoid AmTide Imidacloprid 2F Bounty Discus Tablets Imidacloprid 2F Select Lada 2F Lada 75 WSP Reentry Comments Interval (hours) 12 Systemic. Protection period is reduced if substrate has >30 50 % bark content. Protection onset is translocation delayed in woody plants. Do not apply to soils that are water logged or saturated. Do not apply while bees are foraging. Do not apply to plants in flower (only apply after all flower petals have fallen off). See label for details and rates/restrictions based upon container size and application type. Tablets are formulated to provide consistent delivery of active ingredient over time. Release of active ingredient is dependent on presence of adequate soil moisture. Follow label directions. See AmTide. For greenhouse herbs only (7 day PHI). Do not apply through any irrigation system. Do not foliar apply following a soil application in the same crop. See label for specifics. Systemic. Can incorporate into the medium before planting. Do not apply while bees are foraging. Do not apply to flowering plants. Apply only after all petals have fallen off. Caution on ferns, Crassula, petunias, and lantana. 220

230 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Imidacloprid (continued) Imidacloprid Cyfluthrin Class Trade Name (Formulation) Reentry Interval (hours) Comments 4A Neonicotinoid Mallet 2F T&O 12 Not to be used more than once every 16 weeks. See label for details. Mallet 75 WSP Soil treatment only. Do not make more than 5 applications per year. See label. Mantra 1G For crops grown in flats, on benches, in beds, and in containers. Apply when root systems are well established. See label. Mantra 2F Do not apply through any type of irrigation system. See label. Marathon 1%G See Lada. Beware of pollinator warnings when treating. See label for details. Marathon II Can apply before egglaying activity of target pests. 4A Discus N/G 12 Contact & systemic insecticide for foliar 3A or soil applications. Protection period is reduced if media has >30 50 % bark content. Do not use a neonicotinoid insecticide following application. Highly toxic to bees. Make applications to flowering plants during times when pollinating insects are not present. See label for application types, rates, and details. 221

231 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Insecticidal Soap Isaria fumosorosea Apopka Strain 97 (previously known as Paecilomyces fumosoroseus) NC Class Potassium salts of fatty acids Trade Name (Formulation) Bonide Insecticidal Soap Bayer Insecticidal Soap DES-X Earth-Tone Insecticidal Soap M-Pede Natural Guard Insecticidal Soap 222 Reentry Comments Interval (hours) 12 Kills by contact so complete coverage is essential. Caution on euphorbia, bleeding heart, gardenia, fuchsia, impatiens, poinsettias and new seedlings for phytotoxicity (see label for others). Do not use on new transplants, unrooted cuttings, or plants stressed by drought or heat (>90 F). Apply early in morning or evening or when overcast; do not spray when full sun. Use no more than once per day. Do not spray open blooms or partially open flower buds. See label on plant safety and tank mixing. Safer Insecticidal Soap NC Biological NoFly WP 12 A naturally occurring fungus that is not toxic to humans. The fungus takes 3-7 days to infect and kill the pest. Works best at temperatures between F and requires high humidity. See label for storage and application details. May cause moderate eye irritation. Kinoprene 7A Juvenile hormone analogues Preferal See above. Most effective used at first sign of pests, before high populations develop. Frequent scouting is critical to success. Enstar AQ 4 IGR. Thorough coverage is necessary. Some varieties of roses show delayed damage. See label for specific rates and instructions.

232 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Lambda-cyhalothrin Neem oil (clarified hydrophobic extract of Neem oil) See also : azadiractin Class Trade Name (Formulation) Reentry Interval (hours) Comments 3A Pyrethroid Scimitar GC 24 Not for food crops. Contact insecticide. Thorough coverage of all plant parts is important; a spreader-sticker is recommended. Do not apply through any type of irrigation system. Do not mix with EC formulations or oils. NC Clarified hydrophobic extract of neem oil Triact 70 4 Apply before insects are present in large numbers. Do not apply to wilted or stressed plants or new transplants before roots established. Caution if applying to hibiscus flowers. Do not spray on impatiens flowers or on cut roses. Do not make more than 5 applications per year; do not reapply more than once every 7 days. 70% Neem Oil For immatures only. See above. Do not exceed 1 % rate in the greenhouse. Novaluron 15 Benzoylurea Pedestal 12 IGR; does not control adults. Do not use more than once per generation cycle. Do not make more than 2 applications per crop per year. Do not apply to poinsettias. See label for complete plant list, rates, and instructions. Oil of Rosemary and Peppermint NC Botanical Ecotec 4 Contact insecticide; thorough coverage of all plant parts is important. Repeat application every 5-7 days. Do not use if temperatures are >90 F. 223

233 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Oil (horticultural: Parrafinic, petroleum, soybean) Class Trade Name (Formulation) NC Oil Golden Pest Spray Oil (soybean oil) JMS Stylet Oil# (parafinic) Lesco Horticultural Oil # (mineral oil) Monterey Horticultural Oil (mineral oil) PureSpray Green (mineral oil) Suffoil-X (paraffinic oil) Summit Year Round Spray Oil (mineral oil) SunSpray Ultra-fine Spray Oil (paraffinic oil) TriTek (mineral oil) Ultra-Pure Oil (mineral oil) 224 Reentry Comments Interval (hours) 4 Suffocates eggs and nymphs; complete coverage needed. Do not apply if plants are under any stress, or during periods of prolonged high temperatures combined with high relative humidity. Avoid spraying in greenhouses under overcast conditions. Effectiveness is reduced at temperatures below 50 F. Do not apply through any irrigation system. See label for cautions if using with/before/following application of certain products and for use restrictions, mixing, and other details. Permethrin 3A Pyrethroid Astro 12 Thorough coverage is important for adult control. May cause browning of petals. Marginal leaf burn may occur on salvia, dieffenbachia, and Pteris fern. Avoid spraying chrysanthemum blooms. Permethrin 3.2 Ag See above. Some rose varieties are sensitive. Pymetrozine 9B Pyridine Endeavor (WDG) 12 Systemic, translaminar activity. Insects stop feeding within hours; remain on plant 2-4 days. Some residual activity; controls pests that move onto treated plants. Do not treat poinsettias in bract. Application amounts restricted.

234 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Pyrethrins + Piperonyl butoxide (PBO) 3A 27A Class Pyrethrin Synergist Trade Name (Formulation) Prentox Pyronyl Crop Spray Pyrenone Crop Spray Reentry Comments Interval (hours) 12 A botanical insecticide plus a synergist to flush insects out of hiding and into contact with spray residues. See label for details. Apply when foliage is dry. Do not use on cyclamen or nasturtium. Can be tank mixed with other insecticides. See label. See above. No more than 10 applications/season in greenhouse. See label. Pyreth-It Formula 2 (Prescription Treatment Brand) Pyrethrum TR 225 For adults. See above. For adults. Micro Total Release aerosol formulation for greenhouses; treats up to 3,000 ft 2. See label for specific rates and instructions. Pyrifluquinazon UN Rycar 12 Contact and translaminar insecticide. Causes immediate stop-feed. Thorough spray coverage needed. Do not apply through any irrigation system. Do not harvest cut flowers for 48 hrs after spraying. Do not compost discarded plant materials treated with this product. For non-food crops only. Do not allow pesticide spray solution to run off outside of the application area. Do not apply more than 2 applications per crop cycle.

235 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Pyridaben 21A METI-acaricides Sanmite 75 WP 12 Contact; water soluble packets. Active on adult and nymphal life stages. Thorough coverage of all plant parts is important. Do not apply this product through any irrigation system. Do not use in successive miticide applications; rotate. May be fatal if inhaled. See label for plant lists, specific rates and instructions. Pyriproxyfen 7C Pyriproxyfen Fulcrum 12 IGR for control of eggs, nymphs, and pupae. Apply no more than 2 times per cropping cycle or not >2 times in 6 months. Do not apply to poinsettias after bract formation; see label for details. Do not apply to salvia, ghost plant, Boston fern, gardenia or coral bells. See label for complete plant list, rates, and specific instructions. Spiromesifen 23 Tetronic acid derivative Judo (F) 12 For nymphs; good coverage of the upper and lower leaf surfaces is recommended. Do not apply to geraniums, peperomia, dracaena, certain rose varieties, ivy, fuchsia and others -- see label for phytotoxicity potential. Do not use in successive miticide applications during the same cropping cycle. See label for plant list, rates. 226

236 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Spirotetramat 23 Sulfoximine Kontos 12# Contact, stomach poison, systemic and translaminar insecticide for both knockdown and up to one month residual control. Not a neonicotinoid. Do not apply to edible crops. Start treatments prior to establishment of high pest populations and reapply on an as-needed basis. #See label for drench REI. See label for list of plants, application types, and important plant safety information. Sulfoxaflor (Isatox R ) + Spinetorum 4C 5 Sulfoximine XXpire WG 12 Not a neonicotinoid. Has systemic and translaminar activity. Provides knockdown and up to one month of residual control. Do not apply to edible crops. Do not make more than 2 consecutive applications or more than 4 applications per year. Thiamethoxam 4A Neonicotinoid Flagship 0.22 G 12 Systemic product - allow a minimum of one week for smaller plants to translocate to feeding sites of the target pest. If leaching, allow at least 7 days after watering-in for maximum uptake. See label for application types and rates. Flagship 25 WG Systemic. See above. See label for application directions. 227

237 Table Insecticides for Whitefly Control (continued) Chemical Name IRAC Code Class Trade Name (Formulation) Reentry Interval (hours) Comments Tau-fluvalinate 3A Pyrethroid Mavrik Aquaflow 12 Spray water should be buffered to ph 5-7. Do not apply more than 4 sprays per month. May work slowly on some species. Allow 3 4 days to evaluate performance. Caution on roses and poinsettias. Can also be used as a dip for flower and foliage cuttings. May cause respiratory allergic response. Tolfenpyrad 21A METIinsecticides Hachi-Hachi 12 Contact insecticide for suppression only. Phytotoxic to blooms and some plants. See label for rates for cut flowers. Allow at least 10 days between applications. No more than 2 applications per crop cycle or 4 applications/year. Do not apply to gypsophilia, impatiens, salvia, or poinsettias in bract. See label for other crop tolerances. 228

238 Chapter 12 Insect Control for Greenhouse Vegetable Production and Herbs Gerald E. Brust, IPM Vegetable Specialist Kate Everts, Vegetable Plant Pathologist Insect Control for Greenhouse Vegetable Production The following table lists the insecticides that are labeled for use on greenhouse grown vegetable transplants/ crops. Also included are the targeted pests, crops labeled for use, the pre harvest interval (PHI) and various important comments about the use of these chemicals. These products have been tested and formulated for greenhouse use. Some products, however, while not prohibited from use in the greenhouse lack information on application and use in the greenhouse environment. Note that unless a pesticide label specifically states that a product cannot be used in a greenhouse vegetable crop, the product can be used on those crops for which it is registered. Note: * The EPA has ventilation criteria for greenhouses: If a pesticide is being applied as a fumigant, smoke, mist, fog or aerosol, one of the following ventilation criteria must be met. The concentration of the pesticide in the air is measured to be less than or equal to any inhalation exposure level required on the labeling. If no inhalation exposure level is listed on the labeling, workers must not enter the treated area until after: 10 air exchanges, or 2 hours of ventilation using fans or other mechanical ventilating systems, or 4 hours of ventilation using vents, windows or other passive ventilation, or 11 hours with no ventilation followed by 1 hour of mechanical ventilation, or 11 hours with no ventilation followed by 2 hours of passive ventilation, or 24 hours with no ventilation. 229

239 Table 12.1 Insecticides for Greenhouse Vegetable Production Chemical Name Azadirachtin 18B IRAC Class Tetranortriterpenoid Trade Name Re-entry Interval (hours) Pests and Crop(s) Labeled *Comments Repellant, anti-feedant, caterpillars, leafminers, fungus gnats (except Neemix), mealybugs, rust mites, spider mites, soft and IGR. Controls pests on contact or by ingestion. Apply as spray or drench. Constant agitation is required. Do not mix with Captan, Bordeaux mixtures, and highly scale, whiteflies alkaline products. May and thrips (suppression) Also registered for fungal disease control. reduce waxy bloom on some crops. Can apply via drip irrigation. Reapply every days as necessary. See label for restrictions. 12 For all vegetables and herbs. OMRI listed. IGR and repellent. Spray or drench. Use promptly after mixing (breaks down within 8 hours). Use with buffering agent and surfactant. Spray both sides of leaves. Do not use with Bordeaux mixture, triphenyltin hydroxide, lime sulfur, Rayplex iron, or other highly alkaline materials. Repellant, anti-feedant, and IGR. Apply as spray or drench. Not labeled for fungus gnats. Spray both sides of leaves. Can use in chemigation. Aza-Direct 4 Aphids, Azatrol Azatin XL Ornazin 3% EC Neemix 4.5 Trilogy 4 Insecticide, miticide, and fungicide. Avoid tank mixes with Captan, Sulfur, Bravo, Echo, chlorothalonil, orother similar products. Agroneem Plus 4 Fruiting and baby vegetables OMRI Listed 230

240 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name Bacillus thuringiensis var Aizawai Bacillus thuringiensis var kurstaki Bacillus thuringiensis var israelensis Beauveria bassiana IRAC Class Trade Name Re-entry Interval (hours) 231 Pests and Crop(s) Labeled 11B1 11B2 Microbial Microbial Agree WG XenTari BioBit HP 4 4 Caterpillars only: loopers, tomato fruitworms/ corn earworms, leafrollers, diamondback moths Deliver Dipel DF Dipel Pro DF 11A1 Microbial Gnatrol WDG UN Microbial Botanigard ES Botanigard 22WP Mycotrol O Naturalis L (strain ATCC) 4 For all greenhouse vegetables, herbs, spices, and watercress Fungus gnat larvae For tomatoes, leafy and cole crops, cucumbers, peppers, and eggplants. 4 Aphids, thrips, psyllids, whiteflies For all greenhouse vegetables, herbs and spices *Comments Stomach poison that must be ingested. Most effective against newly hatched, small 1st instar larvae. Insects stop feeding and die 1-5 days later. Can be applied through irrigation system. Do not combine with fungicides or fertilizers containing copper or chlorine. OMRI Listed Larvicide; will not control adult gnats. Can be applied by injection into drip or overhead (sprinkler) irrigation systems. Apply with adequate water by soil drench to sufficiently wet soil surface above and under benches. Do not use in combination with fertilizers or fungicides containing copper or chlorine. Do not apply soil drenches to stressed plants. Slow acting; contains a fungus that infects insects. Must make at least 3 applications at 7-10 day intervals. Thorough spray coverage needed; must contact target pest. Treat when insect levels are low. May need repeated applications may be d. Do not use Botanigard or any ES formulations on tomatoes.

241 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name IRAC Class Trade Name Bifenazate 25 Unclassified Floramite SC Re-entry Interval (hours) Pests and Crop(s) Labeled 12 Twospotted spider mites and European red mite For tomatoes >1 inch in diameter at maturity Buprofezin 16 Thiadiazine Talus 40 SC 12 Whiteflies, mealybugs, and leafhoppers on tomatoes. Chlorfenapyr 13 Pyrazole Pylon 12 Caterpillars (e.g. beet and yellowstriped armyworms, loopers, tomato fruitworm, hornworms, broad mites, twospotted spider mites, tomato russet mites, melon thrips, western flower thrips *Comments Not effective against rust mites or broad mites. Compatible with beneficial predatory mites. Rapidly degrades in alkaline water of high temperature. Use solutions promptly or add a commercial buffering agent. Do not use adjuvants. Use no more than 2 applications per crop/season. IGR targeting active immature stages of insects. Suppresses egg laying and reduces egg viability. Treated pests may remain alive for 3 to 7 days, but feeding damage is low. Apply no more than twice per season, at least 28 days between applications. Do not use on tomato varieties with mature fruit less than 1 inch in diameter. Allow 5-7 days between applications. No more than 3 applications per crop. Do not apply more than 39 fl oz (0.6 lb a.i.) per acre, per crop growing cycle. For peppers, tomato, eggplant, ground cherry, pepinos, tomatillo 232

242 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name IRAC Class Dinotefuran 4A Neonicotinoid Trade Name Safari 20 SG Endosulfan 2A Cyclodiene Thionex 50WP Thionex 3EC Imidacloprid 4A Neonicotinoid Phaser 3EC Benefit 60WP Re-entry Interval (hours) 233 Pests and Crop(s) Labeled 12 Whiteflies, aphids (suppression), leafhoppers For lettuce * Aphids, armyworms, blister beetles, cabbage loopers, Colorado potato and flea beetles, stink bugs, thrips, tomato fruitworms, tomato russet mites, whiteflies For tomatoes 12 For aphids, leafminers, mealybug, whiteflies, thrips (suppression) For broccoli raab, Chinese broccoli, Brussels sprouts, kale, cabbage, cauliflower, collards, rape and mustard greens, ground cherry, kohlrabi, eggplant, lettuce, pepper, potato, tomato, sugarbeet, tomatillo *Comments For vegetable transplants ONLY. Apply as transplant or post-seeding drench. One application per crop. Restricted use. Use lb/a for all pests except whiteflies. For whiteflies: Apply 1 b/100 gal - thorough coverage is needed for high populations. Good coverage necessary. Higher spray volume may be needed for high whitefly populations. Do not make more than 6 applications per year. * See label. Systemic insecticide. Incorporate into media before planting, or use as soil drench via micro, drip irrigation, overhead, ebb and flood irrigation, or hand-held or motorized calibrated irrigation equipment. Protection period is shorter if media has > 30-50% bark content. Irrigate thoroughly after application, allowing no leaching and runout from container for at least three irrigations or 10 days. Do not use packets in a tank mix with products that contain boron or release free chlorine.

243 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name IRAC Class Imidacloprid 4A Neonicotinoid Trade Name Re-entry Interval (hours) Pests and Crop(s) Labeled Lada 12 Aphids, armored scale, (suppression), fungus gnats (larvae only), leafhoppers (inc luding glassy-winged sharpshooter), leafminers, mealybugs (including root mealybugs), soft scale, thrips (suppression), whiteflies For Chinse and raab broccoli,, Brussels Sprouts, cabbage, Chinese cabbage, cauliflower, collards, eggplants, ground cherry, kale, kohlrabi, lettuce, mustard greens, pepinos, pepper, potato, rape greens, sorghum, sugarbeet, tomatillo, and tomato. *Comments For use on vegetable plants intended for resale only. 234

244 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name IRAC Class Imidacloprid 4A Neonicotinoid Trade Name Marathon II Marathon 1G Re-entry Interval (hours) Pests and Crop(s) Labeled 12 Adelgids, aphids, armored scale (suppression), fungus gnats (larvae only), leaf beetles, leafhoppers, leafminers, Japanese beeetles, psyllids, root mealybugs, root weevils, soft scales, thrips (suppression), whiteflies, white grub larvae For Chinese broccoli, cabbage, cauliflower, collards, eggplant, ground cherry, kale, kohlrabi, lettuce, mustard greens, pepinos, potatoes, rape greens, sorghum, sugarbeet, tomatillo, and tomato. *Comments Apply as a broadcast treatment and incorporate into substrate before planting. On established plants, irrigate moderately after application to move active ingredient (a.i.) into root zone. Minimize leaching and runoff for at least 3 irrigations or 10 days, whichever is longer. Adding a nitrogen containing fertilizer, if applicable, into the solution may enhance uptake of the a.i.. Treat as a foliar or soil application. Media with 30% or more bark content may reduce period of protection. Controls fungus gnat larvae in the soil by incorporation, but no adult control. Foliar insect control is by the uptake by a healthy root system translocating the a.i. up into the plant. Control of root mealybug requires thorough incorporation of containerized media. Coverage is essential for control while minimizing leachate. Suppresses thrips on foliage, but not in buds or flowers. 235

245 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name Insecticidal Soap Iron phosphate IRAC Class Trade Name Re-entry Interval (hours) Pests and Crop(s) Labeled UN Fatty acid M-Pede 12 aphids, whiteflies, spider mites, fungus gnats, plant bugs, thrips, caterpillars. Registered on all vegetables, herbs and spices Inorganic Sluggo N/A Slugs on tomatoes Malathion 1B Organophosphate Malathion 8 aquamul 12 Aphids, cucumber beetles, mites, thrips, whiteflies *Comments Works well on whiteflies and aphids if applied frequently. However, do not apply more than 3 applications over a 2 week period Scatter the bait in the plant pots of plants being damaged or around pots on greenhouse benches. Do not apply directly to plants.apply about 1/2 teaspoon per 9-inch pot. OMRI approved. Be sure to check label as the plant harvest interval (PHI) differs for certain crops depending on formulation type. Metaldehyde UN Aldehyde Metaldehyde 2% Nicotine 4B Botanical Fulex Nicotine Fumigator For cucumber, egg plant, head lettuce, endive, leaf lettuce pepper, tomato, onions (bulb & green). 12 Slugs and snails on most vegetables. Ventilation criteria met Aphids, thrips. For cucumbers, lettuce, tomatoes Apply on and beneath greenhouse benches. Keep bait from coming in contact with plants. Restricted use. Smoke fumigator. Apply when foliage is dry. 236

246 Table 12.1 Insecticides for Greenhouse Vegetable Production (continued) Chemical Name IRAC Class Oil UN Paraffinic Oil Pyrethrin + PBO (Piperonyl Butoxide) Soybean Oil Petroleum Oil 3 Botanical Unclassified Trade Name Prescription Treatment Ultra-Fine Oil Pure Spray Green Golden Pest Spray Oil Saf-T-Side Spray Oil Pyrenone crop spray Prentox pyronyl crop spray Prescription Treatment Pyreth-It Re-entry Interval (hours) Pests and Crop(s) Labeled 4 Aphids, beetle larvae, certain caterpillars, leaf miners, thrips, whiteflies, spider mites. 12 after ventilattion criteria met Registered on all vegetables, herbs and spices Aphids, beetles, caterpillars (army worms, loopers), flies, flea beetles, fungus gnats, mealybugs, whiteflies, thrips, spider mites All vegetables, herbs, spices Pyriproxyfen 7C Unclassified Distance 12 Aphids (suppression), fungus gnat and shore fly larvae (apply as a sprench or drench), whiteflies (greenhouse, silverleaf, & sweetpotato) *Comments Must contact pest. Maintain a two week interval between treatments. Test for phytotoxicity for each plant variety before treating. Do not exceed four applications per growing season. Oils can cause foliar injury if very hot and humid. PBO is used to increase effectiveness of Pyrethrin, but is not OMRI approved. Can be tank mixed with other insecticides for enhanced control. See label for details. Micro total release. See directions on can for area coverage. IGR. Do not apply to tomato varieties less than one inch in diameter or to non-bell peppers. Use as a drench or sprench against fungus gnats or shore flies. Do not make more than 2 applications per season. Tomatoes Spinosad 5 Microbial Conserve 4 Lepidopteran SpinTor (caterpillar) 2SC larvae, thrips, leafminers, pinworms on tomatoes Not for use on greenhouse transplants that will go to the field (resistance issues). Excellent product for thrips control. Will not kill sawfly larvae. 237

247

248 Part 3 Disease, Weed, and Algae Management Chapter 13 Chapter 14 Managing Plant Diseases Weed and Algae Control in Commercial Greenhouses

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250 Chapter 13 Managing Plant Diseases Karen Rane, Plant Pathologist Megan McConnell, Extension Assistant Introduction An IPM program helps to prevent and manage plant diseases using environmental, cultural and chemical practices. Ideally, the crop should be monitored regularly for disease symptoms while keeping in mind the three primary factors for disease development: a susceptible host plant, a pathogen present, and favorable environmental conditions. Reducing one or more of these factors will reduce the level of disease. Greenhouse sanitation is extremely important, as is reducing condensation and keeping foliage dry. Eliminating weeds and managing insect pests in the greenhouse also helps to reduce disease problems. Relying on fungicide applications alone without first implementing these cultural practices to reduce disease pressure will result in disease management failures. Refer to other sections of this manual for detailed information on these topics. Diagnosis Before treating any disease, it is important to make an accurate diagnosis of the cause of the symptoms. It is very important to identify the pathogen, its host range, and the optimum conditions for disease development. Often the reason that diseases are not controlled well with chemical applications is because the problem was misidentified and therefore treated with an ineffective product applied at the improper time. Most plant diseases are caused by fungi, but bacteria and viruses can also cause significant losses in greenhouse crops. Noninfectious disorders, such as nutritional deficiencies and environmental damage, can mimic the symptoms of infectious diseases. It may be necessary to submit plants to a diagnostic laboratory for specialized tests to confirm the presence of plant pathogenic microorganisms (see Appendix A). General Guidelines For Fungicides When used in conjunction with greenhouse sanitation and optimum nutrition and environmental conditions for plant health, fungicides can be an excellent tool to help manage certain plant diseases. Applications for control of root diseases are generally used preventively. For most foliage diseases, fungicides are applied when symptoms are first observed, but for highly susceptible crops, or when conditions are known to be favorable for disease, fungicides may be used preventively. Make sure spray coverage is thorough; for soil drench applications, additional irrigation water may be necessary to move the product deeply into the medium. Always follow label directions regarding rates, crops and application method allowed. Fungicide Resistance Management Fungicides are grouped by their mode of action or chemical structure, and the groups are given a code number (called a FRAC code) by the Fungicide Resistance Action Committee. Products having the same FRAC code will attack plant pathogens in a similar manner, even if they have different generic chemical names. In addition, fungicides are classified as systemic (the active ingredient is absorbed into plant tissues) or protectant (the active ingredient does not penetrate plant tissues, but provides a barrier on the plant surface that prevents fungal infection). A third classification system focuses on the specific biochemical processes, or target sites, that a product disrupts in the biology of the fungus. Site-specific fungicides attack one specific biochemical process in fungus physiology, while multi-site fungicides affect a number of different biochemical processes at the same time. Protectant fungicides generally have multiple modes of 241

251 action (multi-site), and are designated with an M in the FRAC code. Most systemic fungicides have a sitespecific mode of action. True fungicide resistance occurs when a genetic mutation occurs in a fungus that allows the biochemical process targeted by the fungicide to continue, making the fungus insensitive to the effects of the fungicide. Fungal pathogens are more likely to develop resistance to products with single target sites because this situation involves a single genetic mutation. If the same single-site fungicide is used repeatedly and exclusively, over time the portion of the population with the mutation will survive and multiply, rendering the fungicide ineffective. Site-specific fungicide groups known to have a high risk of resistance development include benzimidasoles (FRAC 1), phenylamides (4), and strobilurins (11). Resistance is much less likely to develop with multi-site products because a number of simultaneous mutations would be necessary to overcome multiple modes of action. Groups with low risk of resistance development include aromatic hydrocarbons (14), inorganics (M1), dithiocarbamates (M3), and chloronitriles (M5). Several tactics are necessary to avoid fungicide resistance. First, use good cultural practices to improve plant health and reduce diseases, thereby reducing the need for fungicide applications. Apply fungicides only when necessary and always follow label instructions regarding rates and application intervals. Products with high potential for resistance development in the fungal population will provide specific instructions to minimize resistance risk. Use a diversity of products with different modes of action in rotation to provide broad-spectrum disease control. Products with the same FRAC code will have the same general mode of action, so rotate with products with different codes. Plant pathogens are less likely to develop resistance to commercially available combination products, which include two fungicides from different FRAC groups. Tank mixes of products with different modes of action are also effective in reducing fungicide resistance, but always check product labels for guidelines on compatible tank-mix options. Biological Control of Plant Diseases In recent years, scientists have discovered naturally-occurring microorganisms that are able to outcompete plant pathogenic microorganisms, resulting in less plant disease. Some of these biological control agents have been developed into commercial products called biofungicides, and they are becoming common weapons in the greenhouse grower s arsenal for plant disease defense. Biological control microorganisms can reduce plant disease by one or more of four basic methods. Some beneficial fungi or bacteria can outgrow plant pathogenic microorganisms and successfully compete for the nutrients and space available on plant surfaces. Some biocontrol agents produce toxins or antibiotics that inhibit or kill the pathogenic organisms. A third method is parasitism, where the biocontrol agent directly attacks the pathogenic microorganism, using it as a food source. The fourth method is called induced resistance. In this case, the biocontrol agent induces specific biochemical changes in the plant without causing any visible symptoms. These changes make the plant more resistant to infection from plant pathogens, while not directly affecting the pathogen itself. Often, a single biocontrol agent will utilize more than one of these mechanisms for disease control. There are benefits to using biological control microorganisms in a disease management program. In general, these products are safer for workers to use, have shorter re-entry intervals than traditional fungicides and are less phytotoxic. Plant pathogens are less likely to develop resistance to biofungicides, because of varied mechanisms these microorganisms use to control plant pathogens. They can reduce the amount of traditional chemical fungicides needed to finish a crop, thus saving money, and they are among the few disease control options available to organic growers. Biofungicides must be used with standard cultural control practices to be successful. Biocontrol microorganisms are protectants, and are not effective in eradicating a pathogen or in curing infected 242

252 plants. To be effective, biological control agents must be applied before infection takes place. Some of the commercially available biofungicides have a narrower range of target plant pathogens than traditional fungicides, and they may be more expensive. There may also be compatibility problems between biofungcides and some traditional fungicides, and biofungicides require specific storage conditions to remain active. Nevertheless, biofungicides can be used efficiently and effectively when keeping these factors in mind. Biofungicides labelled for use in greenhouse ornamentals include: Rootshield and PlantShield: These products are formulations of Trichoderma harzianum strain T-22, which is labelled for control of soil-borne pathogens such as Pythium, Fusarium, Rhizoctonia and Sclerotinia as well as several foliar pathogens. SoilGard 12G: This is a granular formulation of the soil fungus Gliocladium virens strain GL-21. It is labelled for control of damping-off and root rot due to Pythium, Fusarium and Rhizoctonia. Mycostop: The active ingredient of this product is the soil fungus Streptomyces griseoviridis strain K-16. It is labelled for control of Fusarium diseases, among others. Cease: This formulation of Bacillus subtilis strain QST 713, is labelled for several fungal and bacterial diseases of ornamentals. Actinovate: This product, containing Streptomyces lydicus WYEC108, is labeled for control of Rhizoctonia, Pythium and Fusarium root rots, as well as for suppression of some foliar diseases. DISCLAIMER The following tables serve as guidelines only. The fungicides listed are recommended only if they are registered with the Environmental Protection Agency and your state department of agriculture. If a registration is changed or cancelled, any products listed here are no longer recommended. Before you apply any pesticide, fungicide or herbicide, check with your Extension agent for the latest information. The USER is responsible for using products that are registered for use on specific crops in their own state, and for using products according to label instructions. If any information presented here is inconsistent with the product label, follow the label instructions. Always consult the product label for rates and crops listed. Presence of a product in these tables is not an endorsement, and absence of a labeled product from this list does not imply ineffectiveness. 243

253 Bacterial Diseases Bacteria are tiny, single-celled microorganisms that can multiply at a very rapid rate. Bacterial pathogens require films of water to enter plant tissues and can be spread through splashing water or handling. Symptoms of bacterial diseases on ornamentals include leaf spots, stem rot, vascular wilt and galls. Leaf spots caused by bacteria are initially watersoaked or greasy in appearance, then turn dry and dark to light brown. In some cases, yellow haloes develop near the edges of the brown lesions. Cool, wet conditions favor leaf spots caused by Pseudomonas species. Bacterial leaf spot diseases are becoming more common, particularly in plug production where mist irrigation is often used. Bacterial soft rot of stems is usually associated with wounds caused by handling or insect feeding. Fungus gnat larvae can spread soft rot bacteria. Bacterial soft rot is a common problem with poinsettia cuttings, often causing significant losses. Bacterial leaf spot diseases are common on zinnia and chrysanthemum. Bacterial blight (caused by Xanthomonas pelargonii) is a serious disease of zonal and ivy geranium (Pelargonium x hortorum, P. peltatum) that causes leaf spots, blight, vascular wilt and plant death. Management Strategies: Promote leaf drying by managing irrigation and air circulation. Destroy infected plants, being careful to avoid contact with other plants. Remove all plant debris, and keep tools and benches free of unsterilized soil which may harbor soft rot bacteria. The products listed in the following table may help reduce the spread of bacterial leaf spot diseases, but they must be used along with a strict sanitation program for effective control. Table 13.1 Products for Managing Bacterial Leaf Spot Diseases *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Bacillus subtilis GB03 NC Microbial Companion Liquid Biological Fungicide 4 Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with a ph below 4 or above 9. Apply tank mix solution the same day to assure spore viability. Bacillus subtilis QST 713 strain Copper hydroxide 44 Microbial Cease 4 Apply when environment favors disease development. M1 Inorganic Champ Dry Prill 24* Possible phytotoxicity Nu-Cop 50DF when applied in a spray Nu-Cop 50 WP solution with ph <6.5. Do Nu-Cop HB not apply Champ Dry Prill to hibiscus in flower. See Champ Formula 2 48 label for crop restrictions. Flowable Do not apply just before Cu-Pro 5000 selling season. *24 hrs in greenhouses with specific conditions. 244

254 Table 13.1 Products for Managing Bacterial Leaf Spot Diseases (continued) Chemical Name Code Class Trade Name REI (hour) Comments Copper salts of fatty/rosin acids M1 Inorganic Camelot O 4 May cause some copper toxicity on some plant species. For organic production. See label for cautions when mixing with other products. Copper hydroxide + mancozeb Copper sulfate pentahydrate Mono- and dipotassium salts and Phosphorous acid Reynoutria sachalinensis extract (P) M1 M3 Inorganic Dithiocarbamate Junction 48 Do not apply with a spray solution with ph <6.5. For plants not listed on label, test a small group and observe for 7-10 days for phytotoxicity. Restricted use. M1 Inorganic Phyton 27 24* Compatible with most biopesticides when applied at least 2 days before or after application of the Phyton 35 biopesticide. Do not tank mix with B-NINE and do not apply within 7 days either before or after applications of B-NINE, as burning of leaves may result. Do not tank mix with strongly acidic compounds such as Aliette and do not apply within 14 days either before or after applications of such products * REI in greenhouses when specific conditions met - see label. 33 Ethyl phosphonates Alude Fungicide 4 Apply before disease development. Do not apply to plants under heat and moisture stress. P5 Plant Extract Regalia Biofungicide 4 For use on edible crops as a preventative. Streptomycin NC Streptomycin sulfate Agri-Mycin See label for preventative and curative rates and list of plants that can be treated. 245

255 Botrytis Blight Botrytis blight is an ever-present threat to ornamental plants in the greenhouse. The fungus causes a range of symptoms, including spots and blights on leaves or petals, stem cankers, crown rot, wilting and dampingoff. Botrytis infections may also cause discoloration and death of flower buds and premature loss of flowers. The fungus is spread primarily by the movement of spores in air currents and in splashing water. The fungus commonly invades wounded or senescent tissue, such as fallen flower petals or other fresh plant residues. It can also invade healthy tissue in contact with infected residues. Masses of fuzzy, grayish-brown spores on thin black stalks develop on infected plant tissues under cool, moist, humid, and cloudy conditions. The presence of these spores is diagnostic for confirming Botrytis infections. Management Strategies: Sanitation is critical to Botrytis blight management. Even a small piece of infected debris can generate huge numbers of spores when environmental conditions are favorable to development, and these spores are easily dispersed in air currents during normal greenhouse operations such as watering or spacing plants. Rogue out infected plants and clean up any plant debris on the benches or greenhouse floors. Use plastic bags to collect this material and carry it out of the greenhouse for disposal. If trash containers are used, make sure they have tight-fitting lids and empty the containers frequently. Botrytis spores require free moisture on plant surfaces to germinate and cause infection. Reduce leaf wetness periods, films of moisture and relative humidity in the greenhouse to make conditions unfavorable for Botrytis blight development. Heating and venting the greenhouse for a short time before sunset will help to reduce humidity and condensation (dew formation) on plant surfaces that commonly occurs at nightfall when warm humid air cools down. Use horizontal air flow systems or fans to circulate the air, which will help reduce humidity as well. If overhead irrigation is used, make sure watering occurs early enough in the day to allow plant surfaces to dry off before evening. Proper plant spacing will reduce the humidity within the plant canopy by allowing increased air circulation around the plants. The fungicides listed are effective in managing Botrytis blight, but they must be used in conjunction with cultural practices to obtain maximum disease control. Resistance management is an important consideration when choosing a fungicide for Botrytis control. Resistance to the benzimidazole fungicides is common in Botrytis populations, so these compounds are often ineffective in managing the disease. To minimize the chances of fungicide resistance, it is important to rotate applications of products from different fungicide groups. 246

256 Table 13.2 Fungicides for Managing Botrytis Blight *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage 4 Do not apply more than Mika WG 3 times in sequence. Alternate with a nonstrobilurin product to avoid resistance. Do not apply to leatherleaf fern. Bacillus subtilis GB03 NC Microbial Companion Liquid Biological Fungicide 4 Do not mix with copper based fungicides, solvents, concentrated acids, oxidizing agents or bactericides. Do not mix with products with a ph <4 or >9. Apply tank mix solution the same day to assure viability of spores. Bacillus subtilis QST 713 strain NC Biopesticide Cease 4 Apply when environmental conditions favor disease development. Chlorothalonil M5 Chloronitrile Daconil Ultrex 12 Do not combine with Daconil Weather Stik 54F Echo 720 T+O Echo Ultimate Echo Zn T+O Legend Mainsail 6.0 F Mainsail WDG Manicure 6 FL Manicure Ultra Pegasus 6 L PrimeraOne Chlorothalonil 720 SFT Quali-Pro Chlorothalonil 720 SFT Quali-Pro Chlorothalonil 500 Zn Quali-Pro Chlorothalonil DF Exotherm Termil 247 horticultural oil. See label for other tank mix restrictions. Applications during bloom may damage flowers. For plants not specified on label, apply to a small group to ensure plant safety. Only treat plants when dry and temperature is <75 F. Do not apply to blooms if injury is unacceptable.

257 Table 13.2 Fungicides for Managing Botrytis Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Chlorothalonil Iprodione Thiophanate methyl Tebuconazole M Chloronitrile Dicarboximide Benzimidazole Triazole Quali-Pro Enclave 5.3 F 12 Do not use on Swedish ivy, Boston fern, and Easter cactus. Test a small group of plants not on label before treating large areas. Chlorothalonil + Thiophanate methyl Copper hydroxide Copper hydroxide + mancozeb Copper salts of fatty/ rosin acids M5 1 Chloronitrile Benzimidazole Spectro 90 WDG 12 Do not mix with copper compounds. See label for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. M1 Inorganic Champ Dry Prill 48 Possible phytotoxicity Champ Formula 2 when applied in a spray Flowable solution with ph <6.0. Do not apply to hibiscus plants in flower. Do not apply to plants just before selling season. CuPro 5000 Possible phytotoxicity when applied in a spray solution with ph < 6.5. See label for specific crop restrictions. Nu-Cop 50 DF M1 Inorganic Junction 48 Do not apply with a spray solution with ph <6.5. For plants not listed on M3 Dithiocarbamate label, test a small group; observe for 7-10 days for phytotoxicity. Restricted use. M1 Inorganic Camelot O 4 May cause some copper toxicity on some plant species. For organic production. See label for cautions when mixing with other products. 248

258 Table 13.2 Fungicides for Managing Botrytis Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Copper sulfate M1 Inorganic Phyton 27 24* Compatible with most pentahydrate Phyton 35 biopesticides when applied at least 2 days before or after application of the biopesticide. Do not tank mix with B-NINE; do not apply within 7 days either before or after applications of B-NINE as burning of leaves may result. Do not tank mix with strongly acidic compounds such as Aliette; do not apply within 14 days before or after such applications. * REI in greenhouses when specific conditions met - see label. Cyprodinil Fludioxonil 9 12 Anilinopyrimidines Phenylpyrroles Palladium 12 Excessive runoff of spray or drenches to soil/media may result in stunting or chlorosis. Dicloran 14 Aromatic hydrocarbon Botran 75 W 12 Labeled for use on roses, geraniums and chrysanthemums. May cause plant injury when combined with miscible oil formulations of insecticides. Fenhexamid 17 Hydroxyanilide Decree 50 WDG 4 Do not apply through any irrigation system. Fludioxonil 12 Phenylpyrrole Medallion WDG 12 May cause stunting and/ or chlorosis in impatiens, New Guinea impatiens and geraniums. Do not use on leatherleaf ferns. See label on rates for high organic matter soil mixes. Mozart TR Can use on New Guinea impatiens - see label for crops listed. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with non-strobilurin fungicide. See label on resistance management. 249

259 Table 13.2 Fungicides for Managing Botrytis Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Iprodione 2 Dicarboxamide 26 GT Flowable 12 For plants not specified Chipco Brand Fungicide on label, test on a small number of plants to Chipco N/G evaluate for phytotoxicity before large-scale use. Do Iprodione Pro 2 SE not use as a soil drench on Lesco 18 Plus Turf impatiens or pothos. Do and Ornamental not use on spathiphyllum. Fungicide Nufarm Iprodione SPC Sextant Iprodione + Thiophanate methyl 2 1 Dicarboximide Benzimidazole 26/36 Fungicide 12 Do not use as a soil drench on impatiens or pothos. Do not use on spathiphyllum. Lesco TwoSome Fungicide Nufarm TM + IP SPC Do not drench impatiens, petunias, and pothos. 24 Do not make repeated drenches at high rates to mums. 24 Addition of spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Mancozeb M3 Dithiocarbamate Dithane 75 DF Rainshield T+O Fore 80 WP Rainshield T+O Lesco Mancozeb DG Manzate Pro-Stick T&O Fungicide Manzate Flowable T&O Fungicide Pentathlon DF Pentathlon LF Protect DF Polyoxin D Zinc 19 Polyoxin Affirm WDG 4 For resistance Salt Veranda O Endorse management, alternate with products having different mode of action. Do not apply through any type of irrigation system. 250

260 Table 13.2 Fungicides for Managing Botrytis Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Pyraclostrobin 11 Strobilurin (QoI) Insignia 12 Make no more than 2 sequential applications before rotating with a nonstrobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosilicone-based adjuvants. For plants not specified on label, test on a small group to check for phytotoxicity. Pyraclostrobin + Boscalid 11 7 Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosiliconebased adjuvants. Injury may occur to flowers of impatiens and petunia. Reynoutria sachalinensis extract (P) Streptomyces sp. K61 Streptomyces lydicus WYEC 108 Thiophanate methyl P5 Plant extract Regalia PTO Biofungicide For use on edible crops as a preventative. NC Biopesticide Mycostop Biofungicide 4 For suppression of Botrytis. NC Biopesticide Actinovate SP 1* For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried 1 Benzimidazole 3336 DG Lite 12 Do not tank mix with 3336 WP copper compounds. For 3336 F plants not specifically Nufarm T-Methyl listed on label, trial SPC 4.5 Fungicide applications are recommended. For Nufarm T-Methyl resistance management, SPC 50 WSB rotate with products OHP WP having different mode of OHP F action. Do not apply to Phoenix Phoenix Swedish ivy, Boston fern, T-Bird 85 WDG or Easter cactus.

261 Table 13.2 Fungicides for Managing Botrytis Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Thiophanate methyl + Mancozeb 1 M3 Dithiocarbamate Benzimidazole Zyban WSB 12 Do not use on French marigold or gloxinia. Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 For resistance management, after each application make 2 applications of a nonstrobilurin fungicide. Do not drench to pansy crop or apply to leatherleaf fern. 252

262 Downy Mildew Symptoms of downy mildew include blotchy yellow or brown lesions on leaves, a general yellowing, leaf distortion and stunting. These symptoms can be mistaken for other infectious or noninfectious problems. Check the undersides of symptomatic leaves to look for the gray, brown or white fungal growth typical of downy mildew infections. Common hosts for downy mildew include snapdragon, rose, coleus, sunflower, impatiens, and basil. Management Strategies: Early detection is key for minimizing spread of downy mildew. Remove infected plants promptly, and use protectant fungicides on the rest of the crop. Table 13.3 Fungicides for Managing Downy Mildew *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage 4 Do not treat leatherleaf Mika WG fern. Do not make more than 3 sequential applications before rotating with a nonstrobilurin fungicide. Chlorothalonil + Thiophanate methyl M5 1 Benzimidazole Nufarm TM + CTN SPC 66.6 WDG 12* Do not apply through any irrigation system. *See label for specific criteria. Copper hydroxide Copper hydroxide + Mancozeb Copper salts of fatty/ rosin acids M1 Inorganic Champ Dry Prill 24* Possible phytotoxicity when applied in spray solution of ph <6.5. Do not apply Champ Nu-Cop 50 DF Nu-Cop 50 WP Nu-Cop HB Champ Formula 2 Flowable Cu-Pro Dry Prill to hibiscus in flower. See label for crop restrictions. Do not apply just before selling season. * 24 hrs in greenhouses with specific conditions met. M1 M3 Inorganic Dithiocarbamate Junction 48 Do not apply with a spray solution with ph <6.5. For plants not listed on label, test a small group and observe for 7-10 days for phytotoxicity. Restricted use. M1 Inorganic Camelot O 4 May cause some copper toxicity on some species. For organic production. See label for cautions when tank mixing.

263 Table 13.3 Fungicides for Managing Downy Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Comments Copper sulfate M1 Inorganic Phyton 27 24* Compatible with most pentahydrate Phyton 35 biopesticides when applied at least 2 days before or after application of the biopesticide. Do not tank mix with B-NINE and do not apply within 7 days either before or after applications of B-NINE, as burning of leaves may result. Do not tank mix with strongly acidic compounds such as Aliette and do not apply within 14 days either before or after applications of such products. * REI in greenhouses when specific conditions met - see label. Fixed copper tannate M1 Inorganic Nu-Cop HB 24* Possible phytotoxicity when applied in a spray solution with ph <6.5. *In greenhouses when label restrictions met. Cyazofamid 21 Cyanoimidazole Segway 34.5 EC 12 See label for resistance management guidelines. Do not make more than 4 applications per crop cycle. Dimethomorph 40 Cinnamic acid Stature DM 50% 12 Make no more than 2 consecutive applications. See label for additional resistance management guidelines. Fenamidone 11 Imidazolinone Fenstop 12 For foliar spray, do not make more than 2 applications of maximum rate per crop per season. Fludioxonil + Mefenoxam 12 4 Phenylpyrrole Phenylamide Hurricane 48 Applications to impatiens, New Guinea impatiens, pothos, geranium and Easter lily may cause stunting and/or chlorosis. 254

264 Table 13.3 Fungicides for Managing Downy Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Comments Fluopicolide 43 Acylpicolide Adorn 12 Do not apply sequentially. Do apply more than twice per cropping cycle. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Fosetyl-Al 33 Phosphonate Aliette 80 WDG 12 May not be compatible with foliar fertilizers or copper products. Do not apply within 7 days of copper product application to avoid possible phytotoxicity. Kresoxim methyl 11 Strobilurin (QoI) Cygnus 12 Do not apply more than 8 times per year. Do not apply through any irrigation system. Mancozeb M3 Dithiocarbamate Dithane 75 DF Rainshield T+O Fore 80 WP Rainshield T+O Lesco Mancozeb DG Manzate Flowable T&O Manzate Pro-Stick T&O Fungicide Pentathlon DF Pentathlon LF Protect DF Mandipropamid 40 Mandelic acid amide 24 Addition of spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Micora 4 For use as a foliar protectant fungicide. Do not allow to stand overnight. Agitate before and during application. Mefenoxam 4 Phenylamide Ariel 48 Foliar application. Apply Subdue Maxx only 1 foliar application before alternating with a non-group 4 fungicide. Neem oil NC Triact 70 4 Test first on open blooms. Do not apply to impatiens in bloom. 255

265 Table 13.3 Fungicides for Managing Downy Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Phosphorous 33 Phosphonate Alude Systemic acid-potassium Fungicide salts Alude 45.8% Fosphite KPhite Phostrol Rampart T&O EC 256 Comments 4 Mixing with some foliar fertilizers and copper products may cause phytotoxicity. Test for crop safety before use. Polyoxin D Zinc 19 Polyoxin Affirm WDG 4 For resistance Salt Veranda O management, alternate with products having different mode of action. Do not apply through any type of irrigation system. Endorse Pyraclostrobin 11 Strobilurin (QoI) Insignia 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not listed on label, test on a small group to check for phytotoxicity. Pyraclostrobin + Boscalid Reynoutria sachalinensis extract (P) Streptomyces lydicus WYEC Strobilurin (QoI) Anilide P5 Plant extract Regalia PTO Biofungicide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to impatiens and petunia flowers. 4 For use on edible crops as a preventative. NC Biopesticide Actinovate SP 1* Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried.

266 Table 13.3 Fungicides for Managing Downy Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Thiophanate methyl + Mancozeb Triadimefon + Trifloxystrobin 1 M3 3 Benzimidazole Dithiocarbamate Triazole Comments Zyban WSB 12 Do not use on French marigold or gloxinia. Strike Plus 50 WDG 12 Apply as a preventative. 11 Strobilurin (QoI) Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 For resistance management, make no more than 2 consecutive applications before making 2 applications of a non-strobilurin fungicide. Do not drench pansy crop apply to leatherleaf fern. 257

267 Fungal Leaf Spots Some plants, such as dusty miller, ageratum, pansy and marigold, are occasionally affected by fungal leaf spot diseases. Symptoms range from tiny discolored specks to larger blotches. The lesions may have red or purple margins depending on the host plant and pathogen involved. Most of these diseases affect only one or a few plant species. Fungal leaf spot pathogens survive on infected plant debris and are spread by spores carried in air currents or splashing water. Prolonged leaf wetness usually favors fungal leaf spot disease development. Management Strategies: Inspect plants on a regular basis for fungal leaf spot symptoms. Discard symptomatic plants. Reduce humidity in the greenhouse. Use protectant fungicide sprays if disease continues to spread. Specific fungicides may not control all leaf spot fungi check the label carefully for list of fungal pathogens. Table 13.4 Fungicides for Managing Fungal Leaf Spots *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage 4 Do not treat leatherleaf Mika WG fern. To avoid resistance development, do not make more than 3 applications before rotating with a non-strobilurin fungicide. Bacillus subtilis QST 713 strain NC Biopesticide Cease 4 Apply when environmental conditions favor disease development. Chlorothalonil M5 Chloronitrile Daconil Ultrex 12 Do not combine with Daconil Ultrex horticultural oil. See Daconil Weather Stik label for other tank mix 54F restrictions. Applications during bloom may Echo 720 T+O damage flowers. For Echo Ultimate plants not specified on Echo Zn T+O label, apply to a small Mainsail 6.0 F Mainsail WDG group to ensure plant safety. Pegasus 6L Quali-Pro Chlorothalonil 500 Zn Quali-Pro Chlorothalonil 720 SFT Quali-Pro Chlorothalonil DF 258

268 Table 13.4 Fungicides for Managing Fungal Leaf Spots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Chlorothalonil Iprodione Thiophanate methyl Tebuconazole M Chloronitrile Dicarboximide Benzimidazole Triazole Quali-Pro Enclave 5.3 F 12 Do not use on Swedish ivy, Boston fern, and Easter cactus. Test a small group of plants not on label before treating large areas. Chlorothalonil + Thiophanate methyl Copper hydroxide Copper hydroxide + Mancozeb Copper salts of fatty/ rosin acids M5 1 Chloronitrile Benzimidazole Spectro 90 WDG 12 Do not mix with copper compounds. See label for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. M1 Inorganic Champ Dr Prill 24* Possible phytotoxicity Nu-Cop 50 DF when applied in a spray Nu-Cop 50 WP solution with ph <6.5. Nu-Cop HB Do not apply Champ Dry Prill to hibiscus in flower. Champ Forumula 2 48 See label for specific crop Flowable restrictions. Do not apply Cu-Pro 5000 just before selling season. *24 hrs in greenhouses when specific conditions met - see label. M1 Inorganic Junction 48 Do not apply with a spray solution with ph <6.5. For plants not listed on M3 Dithiocarbamate label, test a small group and observe for 7-10 days for phytotoxicity. M1 Inorganic Camelot O 4 May cause some copper toxicity on some plant species. For organic production. See label for cautions when mixing with other products. 259

269 Table 13.4 Fungicides for Managing Fungal Leaf Spots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Copper sulfate M1 Inorganic Phyton 27 24* Compatible with pentahydrate Phyton 35 most biopesticides when applied at least 2 days before or after biopesticide application. Do not tank mix with B-NINE. Do not apply within 7 days either before or after B-NINE, as burning of leaves may result. Do not tank mix with strongly acidic compounds (e.g. Aliette). Do not apply within 14 days before or after such products. *REI in greenhouse when specific conditions met. Cyprodinil + Fludioxonil 9 12 Anilinopyrimidines Phenylpyrroles Palladium 12 Excessive runoff of spray or drench to substrate may cause stunting or chlorosis. Fludioxonil 12 Phenylpyrrole Medallion 12 May cause stunting and/ or chlorosis in impatiens, New Guinea impatiens and geranium. Do not use on leatherleaf fern. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Iprodione 2 Dicarboxamide Iprodione 2 SE 12 For plants not specified on OHP Chipco N/G label, test on a few plants for phytotoxicity before Sextant large-scale use. Do not use as a soil drench on impatiens or pothos. Do not use on spathiphyllum. Iprodione + Thiophanate methyl 1 2 Benzimidazole Dicarboximide 26/36 Fungicide 12 Do not use as soil drench on impatiens or pothos. Do not use on spathiphyllum. For plants not listed on label, test on a small number for phytotoxicity before use. 260

270 Table 13.4 Fungicides for Managing Fungal Leaf Spots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Kresoxim methyl 11 Strobilurin (QoI) Cygnus 12 Do not apply through any irrigation system. Do not apply more than 8 times per year. Mancozeb M3 Dithiocarbamate Dithane 75 DF Rainshield T+O Myclobutanil 3 Dimethylation inhibitor Polyoxin D Zinc Salt Fore 80 WP Rainshield T+O Lesco Mancozeb DG Manzate Flowable T&O Manzate Pro-Stick Pentathlon DF Pentathlon LF Protect DF 24 Addition of spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Eagle 20 EW Eagle 40 WP 24 Test on plants not listed on label before large scale use. See label for cautions regarding use of plant growth regulators. 19 Polyoxin Affirm WDG 4 For resistance Veranda O management, alternate with products having different mode of action. Do not apply through any type of irrigation system. Endorse Propiconazole 3 Triazole Lesco Spectator T&O 24 For plants not on label, test on a small scale first. Pyraclostrobin 11 Strobilurin (QoI) Insignia 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not specified on label, test on a small group for phytotoxicity. 261

271 Table 13.4 Fungicides for Managing Fungal Leaf Spots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Pyraclostrobin + Boscalid 11 7 Strobilurin (QoI) Anilide Pageant Intrinsic 12 Make no more than 2 sequential applications before rotating to a nonstrobilurin product. Do not use organosiliconebased adjuvants. May injure impatiens and petunia flowers. Streptomyces lydicus WYEC 108 Tebuconazole 3 Triazole Tebuconazole 3.6 Thiophanate methyl Thiophanate methyl + Mancozeb NC Biopesticide Actinovate SP 1* For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried. 12 Do not make more than T&O 4 applications per year at Torque Fungicide the highest rate. 1 Benzimidazole Cleary s 3336 F 12 Do not tank mix with Cleary s 3336 copper compounds. For 50% WP plants not listed on Fungo Flo 50 label, trial applications OHP WP are recommended. For resistance management, OHP F rotate with products Nufarm T-Methyl having different mode of SPC 4.5 F action. Do not apply to Nufarm T-Methyl Swedish ivy, Boston fern, SPC 50 WSB or Easter cactus. Phoenix T-Bird 85 WDG Transom 4.5 F 1 M3 Benzimidazole Dithiocarbamate Zyban WSB 12 Do not use on French marigold or gloxinia. 262

272 Table 13.4 Fungicides for Managing Fungal Leaf Spots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Triadimefon 3 Dimethylation inhibitor Strike 50 Plus WDG 12 Labeled for use on calendula, carnation chrysanthemum, cineraria, crassula, daisy, geranium, gerbera, grape ivy, hydrangea, kalanchoe, poinsettia, rose, snapdragon. Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 For resistance management, make no more than 2 consecutive applications before making 2 applications of a non-strobilurin fungicide. Do not drench pansy crop or apply to leatherleaf fern. 263

273 Fusarium Root and Stem Rot; Fusarium Wilt Although less common than other root rot pathogens, Fusarium can cause root rot in greenhouse crops, particularly in plants that are under stress from other environmental or cultural factors. Symptoms of Fusarium root rot are similar to other root rot diseases. Fusarium species are common inhabitants of untreated field soil. Certain Fusarium subspecies cause vascular wilt of specific crops, such as cyclamen, basil and chrysanthemum. The water-conducting tissue (xylem) of plants infected with Fusarium wilt will often show a reddish or brown discoloration. The vascular wilt subspecies are host specific, while the root rot Fusarium species can infect numerous plant species. Management Strategies: As with other root rot diseases, good sanitation practices help to avoid introduction of Fusarium into a greenhouse. Maintain the vigor of the crop using optimum cultural practices to help plants resist Fusarium root rot infection. While protectant fungicides can help manage Fusarium root rot, fungicides have little effect on Fusarium vascular wilts. Discard plants with vascular wilt symptoms, or with severe root rot. Table 13.5 Fungicides for Managing Fusarium Root Rot *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage Mika WG 4 Do not make more than 3 drench applications before rotating with a non-strobilurin fungicide. Possible phytotoxicity on small plants in seedling/ plug stage test on a small number of plants before large scale use. Bacillus subtilis GB03 NC Microbial Companion Biological Fungicide Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with ph <4 or >9. Can apply through all types of irrigation sytems. Bacillus subtilis QST Microbial Cease 4 OMRI Listed. See label for phytotoxicity details. Etridiazole 14 Aromatic Banrot 8 G 12 Read label about irrigating + hydrocarbon Banrot 40 WP to activate. Thiophanate methyl 1 Benzimidazole Fludioxonil 12 Phenylpyrrole Medallion 12 May cause stunting and/ or chlorosis on impatiens, New Guinea impatiens and geranium. Do not use on leatherleaf fern.

274 Table 13.5 Fungicides for Managing Fusarium Root Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Fludioxonil + Mefenoxam 12 4 Phenylpyrrole Phenylamide Hurricane 48 Applications to impatiens, New Guinea impatiens, pothos, geranium and Easter lily may cause stunting and/or chlorosis. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Iprodione 2 Dicarboxamide Iprodione Pro SE 12 For plants not specified OHP Chipco N/G on label, test on a few plants first. Do not use as Sextant a soil drench on impatiens or pothos. Do not use on spathiphyllum. Iprodione + Thiophanate methyl 2 1 Dicarboxamide Benzimidazole Mancozeb M3 Dithiocarbamate Manzate Pro-Stick T&O 26/36 12 Do not use as a soil drench on impatiens or pothos. Do not use on spathiphyllum. Lesco TwoSome Fungicide Do not drench impatiens, petunias, and pothos. Do Nufarm TM + IP SPC 24 not repeatedly drench mums at high rates A spreader sticker may improve performance. For plants not on label, test a few plants first. Pyraclostrobin 11 Strobilurin (QoI) Insignia Fungicide 12 Make no more than 2 sequential applications before rotating with a nonstrobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosilicone-based adjuvants. For plants not on label, test on a few plants first. Pyraclostrobin + Boscalid 11 7 Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a nonstrobilurin product. Do not use organosiliconebased adjuvants. Injury may occur to flowers of impatiens and petunia.

275 Table 13.5 Fungicides for Managing Fusarium Root Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Streptomyces lydicus WYEC 108 NC Biopesticide Actinovate SP 1* For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried Actino-Iron 4 For incorporation into substrate. Thiophanate methyl Trichoderma hamatum isolate 382 Thiophanate methyl 1 Benzimidazole Phoenix Phoenix T-Bird 85 WDG 1 Benzimidazole Cleary s 3336 DG Lite Cleary s 3336 F Cleary s 3336-WP 50% Fungo Flo 50 Nufarm T-Methyl SPC Granular Fungicide Nufarm T-Methyl SPC 4.5 F Nufarm T-Methyl SPC 50 WSP OHP WP OHP F Phoenix T-Bird 85 Transom 4.5 F 12 Do not tank mix with copper compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products having different mode of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. Incept 12 Incorporate into substrate to suppress diseases. Be sure to mix uniformly. 12 Do not tank mix with copper compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products having different mode of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. 266

276 Table 13.5 Fungicides for Managing Fusarium Root Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Trichoderma harzianum KRL-AG2 NC Biopesticide Plant Shield HC 1.15% RootShield WP 4 0 Check label for information on compatibility with certain RootShield granules fungicides. Triflumazole 3 Dimethylation Terraguard 50W 12 Do not use on impatiens inhibitor Terraguard SC plugs. Some cultivars of impatines ahve shown sensivity to Terraguard SC. Test a small number of plants before treating. 267

277 Powdery Mildew Powdery mildew is characterized by the presence of whitish fungal growth on the surfaces of leaves and stems. Infection of young, expanding leaves or shoots can result in severe distortion. There are many different fungi in the powdery mildew group; some are quite host specific while others can infect a wide range of plants. The fungi obtain nutrients from host plants by penetrating the outermost layer of plant cells. Powdery mildew spores are easily detached from the hyphae on which they develop and are carried by air currents to surrounding plants. Unlike most fungal diseases, leaf wetness is not required for powdery mildew infection. Disease development is favored by high humidity resulting from dry, sunny days followed by cool, moist nights. Management Strategies: Reduce humidity by increasing plant spacing and air circulation and irrigating carefully. Scout plants regularly for the first signs of powdery mildew, as this disease can spread very quickly throughout the crop. Fungicides may be necessary when conditions are favorable for disease. Avoid repeated use of fungicides with the same mode of action to minimize the development of resistance. Table 13.6 Fungicides for Managing Powdery Mildew *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin Heritage 4 Do not apply to leatherleaf (QoI) Mika WG fern. Preventative application only. Do not make more than 2 sequential applications before rotating to another class of fungicide. Bacillus subtilis GB03 NC Microbial Companion Liquid Biological Fungicide 4 Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with ph <4 or >9. Can apply through all types of irrigiation sytems. Bacillus subtilis QST 713 strain 44 Microbial Cease 4 See label for list of plants evaluated for phytotoxicity. OMRI Listed. 268

278 Table 13.6 Fungicides for Managing Powdery Mildew (continued) Chemical Name Code Class Trade Name REI Comments (hour) Chlorothalonil M5 Chloronitrile Daconil Ultrex 12 Do not combine with Daconil Weather Stik horticultural oil. See label for 54F other tank mix restrictions. Echo 720 T+O Applications during bloom Echo Ultimate may damage flowers. For plants not specified on label, Echo Zn T+O apply to a small group to Legend ensure plant safety. Mainsail 6.0 F Mainsail WDG Manicure 6FL Manicure Ultra Pegasus 6 L Quali-Pro Chlorothalonil 720 SFT Quali-Pro Chlorothalonil 500 Zn Quali-Pro Chlorothalonil DF Chlorothalonil + Thiophanate methyl Chlorothalonil Iprodione Thiophanate methyl Tebuconazole Copper hydroxide M5 1 M5 2 1 Inorganic Benzimidazole Chloronitrile Dicarboximide Benzimidazole Spectro 90 WDG 12 Do not mix with copper compounds. See label for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. Nufarm TM + CTN SPC 66.6 WDG Quali-Pro Enclave 5.3 F 269 Do not apply through any irrigation system. *See label for specific criteria. 12 Do not use on Swedish ivy, Boston fern, and Easter cactus. Test a small group of plants not on label before treating large areas. 3 Triazole M1 Inorganic Champ Dry Prill 24* Possible phytotoxicity when Nu-Cop 50 DF applied in a spray solution Nu-Cop 50 WP with ph <6.5. Do not apply Nu-Cop HB Champ Dry Prill to hibiscus in flower. See label for Champ Formula 2 48 specific crop restrictions. Do Flowable not apply to plants just before Cu-Pro 5000 selling season. *24 hrs in greenhouses when specific conditions met.

279 Table 13.6 Fungicides for Managing Powdery Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Comments Copper hydroxide + Mancozeb M1 M3 Inorganic Dithiocarbamate Junction 48 Do not apply with a spray solution with ph <6.5. For plants not listed on label, test a small group and observe for 7-10 days for phytotoxicity. Restricted use. Copper salts of fatty/ rosin acids Copper sulfate pentahydrate Cyprodinil + Fludioxonil M1 Inorganic Camelot O 4 May cause some copper toxicity on some plant species. For organic production. See label for cautions when mixing with other products. M1 Inorganic Phyton 27 24* Compatible with most Phyton 35 biopesticides when applied at least 2 days before or after application of the biopesticide. Do not tank mix with B-NINE and do not apply within 7 days either before or after applications of B-NINE, as burning of leaves may result. Do not tank mix with strongly acidic compounds such as Aliette, and do not apply within 14 days either before or after applications of such products. * REI in greenhouses when specific conditions met. 9 Anilinopyrimidines Palladium 12 Excessive runoff of spray or drenches to soil/substrate 12 Phenylpyrroles may result in stunting or chlorosis. Fluxastrobin 11 Strobilurin (QoI) Hydrogen dioxide Iprodione + Thiophanate methyl Disarm O 12 Rotate with non-strobilurin fungicide. See label about resistance management. NC ZeroTol 0-1 Test for phytotoxicity on a small number of plants before large scale use see label. * REI depends on treatment method. 2 1 Dicarboximide Benzimidazole Lesco TwoSome Fungicide Nufarm TM + IP SPC Do not drench impatiens, petunias, and pothos. Do not 24 make repeated drenches at high rates to mums.

280 Table 13.6 Fungicides for Managing Powdery Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Comments Kresoxim methyl 11 Strobilurin (QoI) Cygnus 12 Do not apply more than 8 times per year. Do not apply through any irrigation system. Mineral oil NC SuffOil-X 4 OMRI listed. See label regarding compatibility with other materials. Myclobutanil 3 Dimethylation Eagle 20 EW 24 Test on plants not listed inhibitor Eagle 40 WP on label before large scale use. See label for cautions regarding use of plant growth regulators. Neem oil NC Triact 70 4 Test first on open blooms. Do not apply to impatiens in bloom. Piperalin 5 Amine Pipron 84.4% L 12 Do not use on hydrangeas when flower buds are visible. Polyoxin D Zinc Salt Potassium bicarbonate 19 Polyoxin Affirm WDG 4 For resistance management, Veranda O alternate with products having different mode of action. Do not apply through any type of irrigation system. Endorse NC Armicarb O 4 Kaligreen MilStop 1 Do apply to New Guinea impatiens with visible buds. Do not use on young pansies. See label about treating poinsettias. 24 For plants not on label, test T&O on a small scale first. Propiconazole 3 Triazole Lesco Spectator Pyraclostrobin 11 Strobilurin (QoI) Insignia Fungicide 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. See label about treating impatiens and petunias. Do not use organosilicone-based adjuvants. For plants not specified on label, test on a small group to check for phytotoxicity. 271

281 Table 13.6 Fungicides for Managing Powdery Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Pyraclostrobin + Boscalid Reynoutria sachalinensis extract (P) Streptomyces lydicus WYEC Strobilurin (QoI) Anilide P5 Plant extract Regalia PTO Biofungicide Comments Pageant 12 Make no more than 2 sequential applications before rotating with a nonstrobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to flowers of impatiens and petunia. 4 For use on edible crops as a preventative. NC Biopesticide Actinovate SP 1* Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried. Sulfur M2 Inorganic Microthiol Disperss 24 OMRI listed. Tebuconazole 3 Triazole Phoenix Skylark 12 Do not make more than 4 applications per year at the Tebuconazole 3.6 F highest rate. T & O Torque Fungicide Thiophanate methyl 1 Benzimidazole Phoenix Phoenix T-Bird 85 WDG 12 Do not tank mix with copper compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products having different mode of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. 272

282 Table 13.6 Fungicides for Managing Powdery Mildew (continued) Chemical Name Code Class Trade Name REI (hour) Comments Thiophanate methyl 1 Benzimidazole Cleary s 3336 F 12 Do not tank mix with copper Thiophanate methyl + Mancozeb 1 M3 Benzimidazole Dithiocarbamate Triadimefon 3 Dimethylation inhibitor Triademefon + Trifloxystrobin Trichoderma harzianum KRL-AG Dimethylation inhibitor Strobilurin (QoI) Trifloxystrobin 11 Strobilurin (QoI) Cleary s 3336 WP 50% Fungo Flo 50 Nufarm T-Methyl SPC 4.5 F Nufarm T-Methyl SPC 50 WSP OHP WP OHP F Phoenix Phoenix T-Bird 85 Transom 4.5 F NC Biopesticide Plant Shield HC 1.15% Triflumizole 3 Dimethylation inhibitor compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products having different mode of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. Zyban WSB 12 Do not use on French marigold or gloxinia. Strike Plus 50 WDG 12 Labeled for use on calendula, carnation chrysanthemum, cineraria, crassula, daisy, geranium, gerbera, grape ivy, hydrangea, kalanchoe, poinsettia, rose, and snapdragon. Armada 50 WDG 12 Excessive rates or applications (<30 days) may result in shortening of the flower stalk. 4 Check label for compatibility with certain fungicides. Compass O 50 WDG 12 For resistance management, after each application make 2 applications of a nonstrobilurin fungicide. Do not apply as drench to pansy or apply to leatherleaf fern. Terraguard 50W 12 Do not use on impatiens Terraguard SC plugs. Some cultivars of impatiens have shown sensivity to Terraguard SC. Test a small number of plants before treating. 273

283 Pythium and Phytophthora Root Rot and Blight Pythium and Phytophthora are in the group of microorganisms called water molds. Both pathogens are soil inhabitants and produce spores that swim in films of water. Both pathogens are favored by poorly drained growing media and excessive moisture. Roots infected with water molds often show a dark, soft, wet rot. In some hosts, the pathogens can invade the lower stem as well, causing a black stem discoloration or crown rot. Symptoms can range from slight stunting and/or chlorosis of infected plants to wilting and plant death. Pythium is more commonly found in greenhouse production, but Phytophthora is usually more aggressive in killing infected plants. Phytophthora can also cause blighting of foliage and stems above the soil line. Pythium root rot is favored by high soluble salts in the growing medium. Both pathogens can survive in surface water sources, such as ponds, and can be distributed through irrigation. Fungus gnats and shore flies can spread Pythium by carrying spores on their bodies or through their feeding activities. Management Strategies: As with all root rot diseases, sanitation is important for keeping the pathogen out of the greenhouse. Field soil in a potting mix should be sterilized before use. Clean pots, tools, and benches with a greenhouse disinfectant. Use a well-drained growing medium, and monitor irrigation practices to avoid saturated conditions. Do not over fertilize and avoid high soluble salt levels in growing mix. If using pond water for irrigation, treat the pond water to reduce Phytophthora and Pythium prior to irrigation. Remove and discard plants with root rot symptoms. Fungicide drenches can help protect uninfected plants. Most fungicides effective against Pythium root rots will also control Phytophthora root and crown rots. Products labeled for Phytophthora foliar blight may not be effective against Pythium root rot. Many Pythium isolates and some Phytophthora isolates are insensitive to metalaxyl and mefenoxam (Subdue and Subdue MAXX), so always rotate with products having different modes of action for the best control of these diseases. Table 13.7 Fungicides for Managing Phytophthora Foliar Blight *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage 4 See label about resistance Mika WG management. Do not apply to leatherleaf fern. Chlorothalonil M5 Chloronitrile Daconil Ultrex 12 Do not combine with Daconil Weather Stik 54F horticultural oil. See label for other tank mix Echo Ultimae T&O restrictions. Applications during bloom may Echo Zn T&O damage flowers. For Echo 720 T&O plants not specified on Lesco Manicure 6 FL label, apply to a small Lesco Manicure Ultra Mainsail WDG group to ensure plant safety. Phoenix Pegaus 6L Quali-Pro Chlorothalonil 500 Zn Quali-Pro Chlorothalonil 720 SFT Quali-Pro Chlorothalonil DF 274

284 Table 13.7 Fungicides for Managing Phytophthora Foliar Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Chlorothalonil + Thiophanate methyl M5 1 Chloronitrile Benzimidazole Spectro 90 WDG 12 Do not mix with copper compounds. See label for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. Copper hydroxide Copper salts of fatty/ rosin acids Copper sulfate pentahydrate M1 Inorganic Champ Dry Prill 24 Possible phytotoxicity when applied in a spray solution with ph <6.5. Do not apply Champ Dry Prill to hibiscus in flower. Nu-Cop 50 HB Nu-Cop 50 WP Champ Formula 2 Flowable CuPro See label for specific crop restrictions. Do not apply just before selling season. *24 hrs in greenhouses when specific conditions met - see label. M1 Inorganic Camelot O 4 May cause some copper toxicity on some plant species. For organic production. See label for cautions when mixing with other products. M1 Inorganic Phyton Compatible with most biopesticides when Phyton 35 applied at least 2 days before or after application of the biopesticide. Do not tank mix with B-NINE and do not apply within 7 days either before or after applications of B-NINE, as burning of leaves may result. Do not tank mix with strongly acidic compounds such as Aliette, and do not apply within 14 days either before or after applications of such products. * REI in greenhouses when specific conditions met.

285 Table 13.7 Fungicides for Managing Phytophthora Foliar Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Cyazofamid 21 Cyanoimidazole Segway 34.5 EC 12 See label for resistance management guidelines. Do not make more than 4 applications per crop cycle. Dimethomorph 40 Cinnamic acid Stature DM 50% 12 Make no more than 2 consecutive applications. See label for resistance management guidelines. Fenamidone 11 Imidazolinone Fenstop 12 For foliar spray, do not make more than 2 applications of maximum rate per crop per season. Fludioxonil + Mefenoxam 12 4 Phenylpyrrole Phenylamide Hurricane 48 May cause stunting and/ or chlorosis on impatiens, New Guinea impatiens, pothos, geranium and Easter lily. Fluopicolide 43 Acylpicolide Adorn 12 Do not apply sequentially. Do apply more than twice per cropping cycle. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Fosetyl-Al 33 Phosphonate Aliette 80 WDG 12 May not be compatible with foliar fertilizers or copper products. Do not apply within 7 days of copper product application to avoid possible phytotoxicity. Mancozeb M3 Dithiocarbamate Dithane 75 DF Rainshield Fore 80 WP Rainshield Lesco Mancozeb DG Protect DF Mandipropamid 40 Carboxylic Acid Amide 24 Addition of spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Micora 4 Do not make more than two foliar or two drench applications per crop; do not make consecutive drench applications. 276

286 Table 13.7 Fungicides for Managing Phytophthora Foliar Blight (continued) Chemical Name Code Class Trade Name REI (hour) Comments Mefenoxam 4 Phenylamide Ariel Subdue MAXX 48 Foliar application. Apply only 1 foliar application before alternating with a non-group 4 fungicide. Some Phytophthora isolates are insensitive to mefenoxam. Phosphorous acid - postassium salts 33 Phosphonate Alude Systemic Fungicide Alude 45.8% 4 Mixing with some foliar fertilizers and copper products may cause Fosphite phytotoxicity. Test for KPhite crop safety before use. Phostrol Propanocarb 28 Carbamate Banol 24 For plants not listed on label, test on a few plants first. Pyraclostrobin 11 Strobilurin (QoI) Insignia Fungicide 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not on label, test on a a few plants first. Pyraclostrobin + Boscalid Streptomyces lydicus WYEC Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. May damage impatiens and petunia flowers. NC Biopesticide Actinovate SP 1* For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension and is active in soil >45 F. *1 hour or until solution has dried. Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 Do not drench pansy or apply to leatherleaf fern. 277

287 Table 13.8 Fungicides for Managing Pythium and Phytophthora Root and Crown Rots *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Bacillus subtilis GB03 NC Microbial Companion Liquid Biological Fungicide 4 Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with a ph <4 or >9. Apply all of the tank solution the same day to assure viability of spores. Bacillus subtilis QST Microbial Cease 4 When conditions favor severe disease development, shorten the spray interval or use a higher rate. Thorough coverage is essential. Cyazofamid 21 Cyanoimidazole Segway 34.5 EC 12 Do not use more than 2 applications per crop cycle for Pythium and Phytophthora soilborne diseases. Dimethomorph 40 Cinnamic acid Stature DM 50% 12 Not effective against Pythium. Do not make more than 2 consecutive applications per crop. Etridiazole 14 Aromatic hydrocarbon Etridiazole + Thiophanate methyl 14 1 Aromatic hydrocarbon Benzimidazole Terrazole 35 WP 12 See label for specific crop Terrazole L list. Irrigate immediately after soil drench for Truban 3 WP improved penetration of Truban 25 EC fungicide. Banrot 8G 12 Read label about Banrot 40W irrigating to activate. Fenamidone 11 Imidazolinone Fenstop 12 See label for resistance management guidelines. Do not make more than 4 drench applications at maximum rate per crop per season. Fludioxonil 12 Phenylpyrrole Medallion WDG 12 May cause stunting and/ or chlorosis on impatiens, New Guinea impatiens and geranium. Do not use on leatherleaf fern. 278

288 Table 13.8 Fungicides for Managing Pythium and Phytophthora Root and Crown Rots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Fludioxonil + Mefenoxam 12 4 Phenylpyrrole Phenylamide Hurricane 48 Applications to impatiens, New Guinea impatiens, pothos, geranium and Easter lily may cause stunting and/or chlorosis. Fluopicolide 43 Acylpicolide Adorn 12 Do not apply sequentially. Do apply more than twice per cropping cycle. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Fosetyl-Al 33 Phosphonate Aliette 80 WDG 12 May not be compatible with foliar fertilizers or copper products. Do not apply within 7 days of copper product application to avoid possible phytotoxicity. Mefenoxam 4 Phenylamide Ariel 48 Soil drench or soil surface Mefonxam 2 AQ Subdue GR Subdue MAXX spray. For plants not specified on label, test on a small number to check for phytotoxicity before large scale use. See label for resistance management comments. Some Pythium and Phytophthora isolates are insensitive to mefenoxam. Phosphorous acid 33 Phosphonate Alude Systemic Fungicide Alude 45.8% 4 Mixing with some foliar fertilizers and copper products may cause Fosphite phytotoxicity. Test for crop safety before use. KPhite Phostrol Rampart T&O 53% EC Propanocarb 28 Carbamate Banol 24 For plants not listed on label, test on a small scale before use. 279

289 Table 13.8 Fungicides for Managing Pythium and Phytophthora Root and Crown Rots (continued) Chemical Name Code Class Trade Name REI (hour) Comments Pyraclostrobin 11 Strobilurin (QoI) Insignia Fungicide 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not specified on label, test on a small group to check for phytotoxicity. Pyraclostrobin + Boscalid 11 7 Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to flowers of impatiens and petunia. Streptomyces sp. K61 Streptomyces lydicus WYEC 108 Trichoderma harzianum KRL-AG2 Trichoderma hamatum isolate 382 NC Biopesticide Mycostop Biofungicide Can treat herb, vegetable, and ornamental seed. Do not treat seeds of dusty miller or melon. Use as drench or spray; can incorporate into substrate. NC Biopesticide Actinovate SP 1* For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension. Active in soil >45 F. *1 hour or until solution has dried Actino-Iron 4 For incorporation into substrate. Biopesticide Plant Shield HC 4 For suppression of 1.15% Pythium root rot. RootShield WP 0 RootShiled granules Incept 12 Incorporate into substrate to suppress diseases. Be sure to mix uniformly.

290 Rhizoctonia Root and Crown Rot Rhizoctonia root rot is common under a range of environmental conditions. Symptoms of Rhizoctonia root rot are similar to those caused by other root pathogens, but Rhizoctonia lesions on lower stems and roots are often drier and lighter in color than other root rots. The fungus tends to be most active in upper soil layers where the medium is drier. Rhizoctonia can also cause foliar blight when plants are crowded and humidity is high. Rhizoctonia is a common soil inhabitant and can produce small sclerotia that can persist for several years in the soil. The primary means of introduction and spread in greenhouse production is the introduction of contaminated soil on greenhouse floors, pots, tools, and plants. Management Strategies: As with other root rot diseases, management is focused on sanitation to keep the pathogen out of the greenhouse. Field soil in a potting mix should be sterilized before use. Clean pots, tools and benches with a greenhouse disinfectant. Remove and discard plants with root rot symptoms. Fungicide drenches can help protect uninfected plants. Table 13.9 Fungicides for Managing Rhizoctonia Root and Crown Rot *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage 4 Do not apply more than Mika WG 2 times in sequence, and alternate with a non-strobilurin product to avoid resistance development. Do not apply to leatherleaf fern. Bacillus subtilis GB03 NC Microbial Companion Liquid Biofungicide 4 Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with a ph below 4 or above 9. Apply all of the tank mix the same day to assure viability of spores. Bacillus subtilis QST 713 Chlorothalonil + Thiophanate methyl 44 Microbial Cease 4 When conditions favor severe disease development, shorten the spray interval or use a higher rate. Thorough coverage is essential for effective disease control. M5 Chloronitrile Spectro 90 WDG 12 Do not mix with copper compounds. See label 1 Benzimidazole for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. 281

291 Table 13.9 Fungicides for Managing Rhizoctonia Root and Crown Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Etridiazole 14 Aromatic Banrot 8 G 12 Read label about + hydrocarbon Banrot 40 WP irrigating to activate. Thiophanate methyl 1 Benzimidazole Fludioxonil 12 Phenylpyrrole Medallion WDG 12 May cause stunting and/ or chlorosis in impatiens, New Guinea impatiens and geranium. Do not use on leatherleaf fern. Fludioxonil + Mefenoxam 12 4 Phenylpyrrole Phenylamide Hurricane WDG 48 Applications to impatiens, New Guinea impatiens, pothos, geranium and Easter lily may cause stunting and/ or chlorosis. Flutalonil 7 Carboximide Contrast 70 WSP 12 Trial applications ProStar 70 WDG recommended for plants not specified on label see label for details. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Iprodione 2 Dicarboxamide 26 GT Flowable 12 For plants not specified Lesco 18 Plus Turf and Ornamental Fungicide on label, test on a small number of plants to evaluate for phytotoxicity NuFarm Iprodione before large-scale use. Pro SPC Do not use as a soil OHP Chipco drench on impatiens or N/G pothos. Do not use on spathiphyllum. OHP Chip Brand Fungicide Iprodione + Thiophanate methyl 2 1 Dicarboximide Benzimidazole 26/36 Fungicide 12 Do not use as a soil drench on impatiens or pothos. Do not use on spathiphyllum. Lesco TwoSome Fungicide Do not drench impatiens, petunias, and pothos. Nufarm TM + IP SPC 24 Do not make repeated drenches at high rates to mums. 282

292 Table 13.9 Fungicides for Managing Rhizoctonia Root and Crown Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Mancozeb M3 Dithiocarbamate Manzate Pro-Stick T&O 24 Addition of spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Pentachloronitrobenzene 14 Aromatic hydrocarbon Terraclor Soil drench or pre-plant bulb soak. See label. Polyoxin D Zinc Salt 19 Polyoxin Affirm WDG 4 For resistance Veranda O management, alternate with products having different mode of action. Do not apply through any type of irrigation system. Endorse Pyraclostrobin 11 Strobilurin (QoI) Insignia Fungicide 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not specified on label, test on a small group to check for phytotoxicity. Pyraclostrobin + Boscalid Streptomyces sp. K Strobilurin (QoI) Anilide NC Biopesticide Mycostop Biofungicide Pageant Intrinsic 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to flowers of impatiens and petunia. 4 Can be applied as a seed treatment for vegetables, herbs, and ornamentals. Do not treat seeds of dusty miller or melon. Can be incorporated into substrate and applied as a drench or spray. 283

293 Table 13.9 Fungicides for Managing Rhizoctonia Root and Crown Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Streptomyces lydicus WYEC 108 NC Biopesticide Actinovate SP 1 For use on vegetables and herbs. Product is completely soluble and does not require agitation to keep in suspension. Active in soil >45 F. *1 hour or until solution has dried Actino-Iron 4 For incorporation into substrate. Thiophanate methyl Trichoderma hamatum isolate 382 Trichoderma harzianum KRL-AG2 1 Benzimidazole Cleary s DG Lite 12 Do not tank mix with Cleary s 3336 F copper compounds. For Cleary s 3336 WP plants not specifically 50% listed on label, trial Fungo Flo 50 applications are recommended. For Nufarm T-Methyl resistance management, SPC 4.5 F rotate with products Nufarm T-Methyl having different mode of SPC Granular action. Do not apply to Nufarm T-Methyl Swedish ivy, Boston fern, SPC 50 WSB or Easter cactus. OHP WP OHP F Transom 4.5 F Incept 12 Incorporate into substrate to suppress diseases. Be sure to mix uniformly. NC Biopesticide RootShield WP 0 Check label for RootShield Granules compatibility with certain fungicides. Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 Do not use more than 2 consecutive applications before rotating with a non-strobilurin fungicide. Do not apply as a drench to pansy or apply to leatherleaf fern. Triflumizole 3 Dimethylation inhibitor Terraguard 50W 12 Do not use on impatiens plugs. Some impatiens Terraguard SC cultivars have shown sensitivity to Terraguard SC. Test a few plants first before using. 284

294 Rusts Rust diseases are caused by a group of highly specialized fungi with complex life cycles. They are obligate parasites and must infect living plant tissue to grow and survive. Some rusts need two different host plants to complete their development, while others require only one host. The disease gets its name from the orange or brown spores produced by most of these fungi in at least one part of their life cycle. Spores develop in erupent structures called pustules, which often develop in concentric rings on the foliage. Rust diseases can be spread through the air via wind-blown spores or through the introduction of infected plants in the greenhouse. Rust spores can also spread plant to plant through splashing water. High humidity and long leaf wetness periods favor rust disease development. Snapdragon, geranium and fuchsia are among greenhouse ornamentals that can be infected. Chrysanthemum white rust, caused by Puccinia horiana is a federally regulated plant pathogen, and subject to quarantine restrictions. Incidents of suspected Chrysanthemum white rust must be reported to state horticulture officials. Management Strategies: Management of rust diseases starts with inspecting plants when they arrive. Careful scouting and roguing out of any symptomatic plants is a great way to avoid plant disease problems. Rust fungi can produce large quantities of spores in a relatively short period of time, so even a small number of infected plants can cause an epidemic. There are several effective fungicides for controlling rust diseases, but these are preventative, not curative. Fungicide treatment is no substitute for sanitation. Table Fungicides for Managing Rusts *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Azoxystrobin 11 Strobilurin (QoI) Heritage Mika WG 4 Do not make more than 3 applications before rotating with a nonstrobilurin fungicide. Bacillus subtilis QST Microbial Cease 4 When conditions are favorable for severe disease development, shorten spray interval or use a higher rate. Thorough coverage is essential. 285

295 Table Fungicides for Managing Rusts (continued) Chemical Name Code Class Trade Name REI (hour) Comments Chlorothalonil M5 Chloronitrile Daconil Ultrex 12 Do not combine with Daconil Weather Stik 54 F horticultural oil. See label for other tank mix Echo 720 T+O restrictions. Applications Echo Ultimate during bloom may damage flowers. For Echo Zn T+O plants not specified on Lesco Manicure 6 FL label, apply to a small Lesco Manicure Ultra group to ensure plant Mainsail 6.0 F safety. Mainsail WDG Pegasus 6L Quali-Pro Chlorothalonil 720 SFT Quali-Pro Chlorothalonil 500 Zn Quali-Pro Chlorothalonil DF Chlorothalonil Iprodione Thiophane methyl Tebuconazole Chlorothalonil + Thiophanate methyl Copper sulfate pentahydrate M M5 1 Chloronitrile Dicarboximide Benzimidazole Triazole Chloronitrile Benzimidazole Quali-Pro Enclave 5.3 F Do not use on Swedish ivy, Boston fern, and Easter cactus. Test a small group of plants before treating large areas. Spectro 90 WDG 12 Do not mix with copper compounds. See label for details. Do not use on Boston fern, Swedish ivy, or Easter cactus. M1 Inorganic Phyton 27 24* Compatible with most Phyton 35 biopesticides used at least 2 days before or after application of biopesticide. Do not tank mix with B-NINE or apply within 7 days before or after application of B-NINE or leaf burn may result. Do not tank mix with strongly acidic compounds (i.e. Aliette). Do not apply within 14 days before or after these applications. * REI in greenhouses with specific conditions.

296 Table Fungicides for Managing Rusts (continued) Chemical Name Code Class Trade Name REI (hour) Comments Flutalonil 7 Carboximide ProStar WDG 12 Make no more than 4 applications per year. Fluxastrobin 11 Strobilurin (QoI) Disarm O 12 Rotate with nonstrobilurin fungicide. See label for resistance management guidelines. Kresoxim methyl 11 Strobilurin (QoI) Cygnus 12 Do not apply more than 8 times per year. Do not apply through any irrigation system. Mancozeb M3 Dithiocarbamate Dithane DF 24 Addition of spreader Dithane 75 DF Rainshield T+O sticker may improve performance. For plants Fore 80 WP not specified on label, Rainshield T+O trial applications are Lesco Mancozeb DG recommended. Manzate Florable T&O Manzate Pro-Stick T&O Fungicide Pentathlon DF Pentathlon LF Protect DF Mineral oil NC SuffOil-X 4 OMRI listed. See label regarding compatibility with other materials. Myclobutanil 3 Dimethylation Eagle 20 EW 24 Test plants not on label inhibitor Eagle 40 WP before large scale use. See label for cautions on plant growth regulators. Neem Oil NC Triact 70 4 See label regarding sensitive speces. Propiconazole 3 Triazole Lesco Spectator T&O 24 For plants not on label, Fungicide test on a small scale first. Pyraclostrobin 11 Strobilurin (QoI) Insignia 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. Test small groups of plants not on label before treatment. 287

297 Table Fungicides for Managing Rusts (continued) Chemical Name Code Class Trade Name REI (hour) Comments Pyraclostrobin + Boscalid 11 7 Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to flowers of impatiens and petunia. Sulfur M2 Inorganic Microthiol Disperss 24 OMRI Listed. Tebuconazole 3 Triazole Tebuconazole 3.6 T&O Torque Fungicide 12 Do not make more than 4 applications per year at the highest rate. Thiophanate methyl 1 Benzimidazole Cleary s 3336 F 12 Do not tank mix with Triadimefon + Trifloxystrobin 3 Triazole Cleary s 3336 WP 50% Fungo Flo 50 Nufarm T-Methyl SPC 4.5 F Nufarm T-Methyl SPC 50 WSB OHP WP OHP F Transom 288 copper compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products with different modes of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. Strike Plus 50 WDG 12 Phytotoxicity noted on petunias, violets, and New Guinea impatiens. 11 Oximino-acetate Trifloxystrobin 11 Strobilurin (QoI) Compass O 50 WDG 12 For resistance management, do not use more than 2 consecutive applications before rotating with a nonstrobilurin fungicide. Do not apply as a drench to pansy or apply to leatherleaf fern. Triflumizole 3 Dimethylation inhibitor Terraguard 50W 12 Do not use on impatiens Terraguard SC plugs. Some cultivars of impatiens have shown sensitivity to Terraguard SC. Test a small number of plants before treating large areas.

298 Sclerotinia Blight and Crown Rot Sclerotinia blight, also called white mold, can occur on a wide variety of herbaceous ornamentals as well as vegetables, field crops and weeds. Symptoms include crown rot, stem rot, and flower blight. The pathogen produces hard, black structures called sclerotia that are irregular in shape and about 1/8 to 1/4 inch in size. Sclerotia may appear on the plant or soil surface, or inside the stem of infected plants. Under conditions of high humidity, fluffy white fungal growth develops on infected plant parts as well, giving the disease the name white mold. Sclerotia are very resistant to environmental extremes, and can survive in soil and plant debris for several years. The disease is primarily spread through movement of sclerotia in soil or infected plants. Under certain environmental conditions, sclerotia can produce cup-like structures that release airborne spores. Management Strategies: Sanitation is critical for managing Sclerotinia blight. Do not use unsterilized field soil in potting mixes. Avoid introducing untreated field soil to the greenhouse on tools or equipment, and keep weeds under control. Discard infected plants promptly. Fungicide drenches can help protect plants from infection. Table Fungicides for Managing Sclerotinia Blight and Crown Rot *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Bacillus subtillis GB03 NC Microbial Companion Liquid Biological Fungicide 4 Do not mix with copper based fungicides, concentrated acids, solvents, oxidizing agents or bactericides. Do not mix with products with a ph below 4 or above 9. Apply all of the tank mix solution the same to assure viability of spores. Chlorothalonil + Thiophanate methyl Cyprodinil + Fludioxonil Iprodione + Thiophanate methyl M Chloronitrile Benzimidazole Anilinopyrimidines Phenylpyrroles Dicarboxamide Benzimidazole Spectro 90 WDG 12 Do not mix with copper compounds. See label for additional tank mix restrictions. Do not use on Swedish ivy, Boston fern or Easter cactus. Palladium 12 Excessive runoff of spray or drenches to soil/ substrate may result in stunting or chlorosis. Nufarm TM + IP SPC Fungicide 12 Use as a drench for Sclerotinia management. Do not drench impatiens, petunias, and pothos. Do not make repeated drenches at high rates to mums. 289

299 Table Fungicides for Managing Sclerotinia Blight and Crown Rot (continued) Chemical Name Code Class Trade Name REI (hour) Mancozeb M3 Dithiocarbamate Manzate Flowable T&O Manzate Pro-Stick T&O Pentathlon LF 37% Protect DF Comments 24 Addition of a spreader sticker may improve performance. For plants not specified on label, trial applications are recommended. Pentachloronitrobenzene 14 Aromatic hydrocarbon Terraclor Soil drench or pre-plant soak - see label. Pyraclostrobin 11 Strobilurin (QoI) Insignia 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not apply to impatiens or petunias in flower. Do not use organosiliconebased adjuvants. For plants not specified on label, test on a small group to check for phytotoxicity. Pyraclostrobin + Boscalid Stretomyces lydicus WYEC Strobilurin (QoI) Anilide Pageant 12 Make no more than 2 sequential applications before rotating with a non-strobilurin product. Do not use organosilicone-based adjuvants. Injury may occur to flowers of impatiens and petunia. NC Biopesticide Actinovate SP 1* Product is completely soluble and does not require agitation to keep in suspension. Product is active in soil above 45 F. *1 hour or until solution has dried. Actino-Iron 4 For incorporation into substrate. 290

300 Table Fungicides for Managing Sclerotinia Blight and Crown Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Thiophanate methyl 1 Benzimidazole Cleary s DG Lite 12 Do not tank mix with Cleary s 3336 F Cleary s 3336-WP 50% Cleary s 3336-G 2% Fungo Flo 50 Nufarm T-Methyl SPC 4.5 F Nufarm T-Methyl SPC 50 WSB Nufarm T-Methyl SPC Granular OHP WP Phoenix Phoenix T-Bird 85 WDG TM 4.5 T&O T-Storm 50 WSB T-Storm Flowable Transom 4.5 F copper compounds. For plants not specifically listed on label, trial applications are recommended. For resistance management, rotate with products having different mode of action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. 291

301 Thielaviopsis Root Rot Thielaviopsis root rot disease is also called black root rot, due to the discrete black lesions present in infected roots. In severe cases, the root system is almost entirely black. The dark color is due to numerous dark, thick-walled spores produced by Thielaviopsis in infected plant tissues. Plants with Thielaviopsis root rot are often stunted and have chlorotic (yellowing) foliage. The pathogen has a wide host range, but the most common greenhouse ornamentals affected include pansy, vinca, calibrachoa, and fuchsia. Thielaviopsis root rot is favored by high soil ph (6.5 and higher) and poor drainage. Management Strategies: Keep the growing medium ph at 6 or below to reduce Thielaviopsis problems. As with all root rot diseases, sanitation is key to keeping the fungus out of the greenhouse. Discard diseased plants. Fungicides applied as a soil drench can help protect roots from Thielaviopsis infection. Table Fungicides for Managing Thielaviopsis Root Rot *Refer to disclaimer statement on page 243. Chemical Name Code Class Trade Name REI (hour) Comments Etridiazole 14 Aromatic Banrot 8 G 12 Read label about + hydrocarbon Banrot 40 W irrigating to activate. Thiophanate methyl 1 Benzimidazole Fludioxonil 12 Phenylpyrrole Medallion 12 May cause stunting and/ or chlorosis in impatiens, New Guinea impatiens and geranium. Do not use on leatherleaf fern. Fludioxonil + Mefenoxam Iprodione + Thiophanate methyl Phenylpyrrole Phenylpyrrole Dicarboximide Benzimidazole Polyoxin D 19 Peptidyl pyrimidine nucleoside Hurricane 48 Applications to impatiens, New Guinea impatiens, pothos, geranium and Easter lily may cause stunting and/or chlorosis. Nufarm TM + IPM SPC 12 Do not drench impatiens, petunias, and pothos. Do not make repeated drenches at high rates to mums. Affirm 4 Apply as a drench every Endorse days for crown and root rot diseases. 292

302 Table Fungicides for Managing Managing Thielaviopsis Root Rot (continued) Chemical Name Code Class Trade Name REI (hour) Comments Thiophanate 1 Benzimidazole Cleary s DG Lite 12 Do not tank mix with methyl Cleary s WP copper compounds. For Cleary s 3336 F plants not specifically listed on label, trial applications are recommended. Cleary s 3336 G 2% Fungo Flo 50 For resistance management, rotate with products Nufarm T-Methyl SPC 4.5 F having different mode of Nufarm T-Methyl SPC 50 WSB Nufarm T-Methyl action. Do not apply to Swedish ivy, Boston fern, or Easter cactus. SPC Granular OHP WP OHP F Phoenix Phoenix T-Bird 85 WDG T-Storm 50 WSB Transom 4.5 F Trichoderma hamatum isolate 382 Trichoderma harzianum KRL-AG2 Incept 12 Incorporate into substrate to suppress diseases. Be sure to mix uniformly. NC Biopesticide PlanShield HC 4 Check label for 1.15% information on RootShield WP 0 compatibility with certain RootShield Granules fungicides. Terraguard 50W 12 Do not use on impatiens Terraguard SC plugs. Some cultivars of impatiens have shown sensitivity to Terraguard SC. Test a small number of plants before treating large areas. Triflumizole 3 Dimethylation inhibitor 293

303 Virus Diseases Virus symptoms are often quite striking and distinctive. Chlorotic mottling, ringspots and line patterns on the foliage or stems may occur. Stunting is commonly observed. The single most important virus in ornamental plant production is Impatiens Necrotic Spot Virus (INSV). New Guinea and common impatiens are often affected, although the virus can infect a wide range of bedding plants, pot crops and weed hosts. Symptoms of INSV on impatiens include dark black or purple lesions on the stems and leaf veins and dark ringspots or blotches on leaves. Infected plants are stunted, and young leaves may be small and misshapen. INSV causes bleached white spots and rings on leaves and stems of snapdragons. INSV is spread by western flower thrips feeding. In recent years, viruses have been associated with new crops that are propagated vegetatively through cuttings. Tobacco mosaic virus (TMV), calibrachoa mottle virus (CbMV), tobacco rattle virus (TRV), and cucumber mosaic virus (CMV) have been found in various bedding plants and pot crops. TMV is a very stable virus with a wide host range, and any practices that move infected plant sap (handling plants, taking cuttings, potting) can spread the virus easily throughout a crop. Management Strategies: Inspect plants regularly for virus symptoms. Test symptomatic plants for virus diseases to have a definitive diagnosis of specific virus problems. Samples may be sent to a diagnostic laboratory or commercial virus-testing company, or may be tested in-house using commercially available virus test kits. Maintain strict weed control inside the greenhouse as well as around the outside walls. Destroy plants showing virus symptoms. Manage thrips to minimize the spread of INSV (refer to Thrips section for more information). Place plants that are most susceptible to the virus in the center of the greenhouse, away from doors, vents and sidewalls. 294

304 Table Fungicides and Bactericides for Greenhouse Vegetable Production Fungicide (Trade name, Product Source) Re-entry Interval Basic Copper Sulfate (Cuprofix Disperss; United Phosphorus, Inc.) 48 hr. REI Bacillus pumilus (Sonata; AgraQuest) 4 hr. REI Bacillus subtilis (Companion, Growth Products LTD) 4 hr, REI Chlorothalonil plus Potassium Phosphite (Catamaran; Luxembourg Pamol, Inc.) 12 hr. REI Coniothyrium minitans (Contans; SipcamAdvan) 4 hr. REI Copper Hydroxide (Kocide 101, Kocide 2000, Kocide 4.5LF, Kocide DF; DuPont) 24 hr. REI Copper Salts of fatty and rosin acids (Camelot; Whitemire Micro-Gen) 12 hr. REI Cuprous Oxide (Nordox, Monterey Chemical, Co.) 24 hr. REI Target Diseases Labeled Plants Comments Many diseases including angular leaf spot, downy mildew. Alternaria blight, anthracnose, bacterial blight, etc. Early blight, late blight, downy mildew, powdery mildew Suppression of soilborne and foliar diseases including damping off, root rot and early blight Late blight Sclerotinia sclerotiorum, Sclerotinia minor Leaf spots, anthracnose and bacterial spots Alternaria blight, downy mildew, angular leaf spot, powdery mildew, scab, gray mold, bacterial soft rot, bacterial spot, Cercospora leaf spot, etc. Bacterial spot and speck, Alternaria leaf spot, anthracnose, early and late blight, etc. Vegetables including cucumbers, eggplant, peppers, tomatoes Many vegetables including brassicas, bulb vegetables, cucurbits, fruiting vegetables, and leafy vegetables Many including fruiting, leafy vegetables, cucurbits, cole crops and herbs Tomatoes Many vegetables including leafy vegetables, brassicas, legumes, fruiting vegetables, and bulb vegetables See labels for specific crops including cucumber, eggplant, pepper, and tomatoes Vegetables such as broccoli, cabbage, cucurbits, tomato, pepper, and lettuce Eggplant, pepper, and tomato Crops grown in the greenhouse may be more sensitive to copper injury so the user should determine plant sensitivity. OMRI approved. May be used in hydroponics, plug production and soilless production systems. Most effective used preventatively. OMRI approved. Contains a beneficial fungus. Do not allow to stand overnight after mixing. Acts as a preventative. See labels for specific usage instructions. Determine if Camelot can be used safely prior to use. Observe for 7 to 10 days for symptoms of injury. See label for specific usage instructions. 295

305 Table Fungicides and Bactericides for Greenhouse Vegetable Production (continued) Fungicide (Trade name, Product Source) Re-entry Interval Cyazofamid (Ranman, FMC Corporation) 12 hr. REI Dicloran (Botran 75-W, Gowan Company) 12 hr. REI Fenhexamid (Decree, Arysta Life Science) 4 hr. REI Horticultural oil (Ultra-Fine oil; Whitmire Micro-Gen) 4 hr. REI Hydrogen Dioxide (Oxidate, Zerotol; BioSafe Systems LLC) 1 hr. REI Kaolin (Surround WP, Nova Source Tessenderlo Group) 4 hr. REI Mancozeb (Dithane zm45, DF, Dow AgroSciences LLC) 24 hr. REI Mandipropamid (Micora, Syngenta) 4 hr. REI Target Diseases Labeled Plants Comments Pythium damping off and Basil downy mildew Sclerotinia and Sclerotium rots, pink rot, gray mold, leaf blight and neck rot Botrytis Powdery mildew Anthracnose, downy mildew, powdery mildew, Pythium root rot Tomato greenhouse transplant production and basil Many vegetables including leaf lettuce, cucumbers, rhubarb, tomatoes and greenhouse seed potatoes or transplants. Tomatoes, field tomato transplants grown in greenhouse, cucumbers and lettuce Cucurbits, melons, and squash Many, including cole crops, cucurbits, leafy vegetables, peppers, and tomatoes Drench transplant tray with fungicide at planting or up until one week before transplant. See label for details. May cause leaf bronzing on lettuce. Use adequate volume of water. Protectant fungicide with some plant back restrictions. See label for details. Make application when disease is first noticed. See label for information on plant safety. Use lower label rates in the greenhouse. Strong oxidizing agent. Contact, oxidizing sanitizer. (Active ingredient: hydrogen peroxide) Powdery mildew Cucurbit vegetables Product forms a white clay film on leaves and fruit. Leaf spot diseases, seed treatment for damping off, seed rots and seedling blights Downy mildews, blue mold, and late blight, and suppression of Phytophthora blight Tomatoes and others Brassicas, peppers, eggplants, leafy vegetables, and tomatoes. Basil transplants for resale. Broad-spectrum protectant fungicide. Registered for closed greenhouses with permanent flooring on transplants for re-sale to consumers. See label for specific instructions. 296

306 Table Fungicides and Bactericides for Greenhouse Vegetable Production (continued) Fungicide (Trade name, Product Source) Re-entry Interval Pentachloro-Nitrobenzene PCNB (Terraclor 75 WP, Terraclor Flowable, Terraclor 15G; Chemtura Corp.) 12 hr. REI Penthiopyrad (Fontelis, DuPont) 12 hr. REI Petroleumoil (Saf-T-Side spray oil, Brandt Consolidated 12 hr. REI Potassium Bicarbonate (Armicarb 100, Helena Chemical Co.; Milstop, BioWorks, Inc.; Kaligreen, Taogossi Co., Ltd) 4 hr. REI Potassium salts of fatty acids (M-Pede, Dow Agro Sciences) 12 hr. REI Propamocarb Hydrochloride (Previcur Flex; Bayer Crop Science) 12 hr. REI Pyraclastrobin plus Boscalid (Pageant Intrinsic, BASF Corp) 12 hr. REI Pyrimethanil (Scala, Bayer Crop Science) 12 hr. REI Streptomyces griseovirdis strain K61 (Mycostop, Mycostop Mix, Vedera Oy Finland) 4 hr. REI Target Diseases Labeled Plants Comments Root and stem rot, damping off (Rhizoctonia solani, Pellicularia filamentosa) Many, including gummy stem blight, Sclerotinia stem rot, anthracnose, leaf spots, powdery mildew 297 Vegetable bedding plants-only containergrown beans, broccoli, Brussel sprouts, cabbage, peppers, cauliflower, tomatoes Tomatoes, peppers and edible peel cucurbits Flowable and 75WP: Apply as a soil drench. 15G: Used as growing media mix. See label for additional information. See label for specific usage instructions. Powdery mildew Cucurbit vegetables Contact fungicide. See lable about phytotoxicity issues. Powdery mildew and others Many vegetables including cabbage, cucumber, eggplant, broccoli, cauliflower, lettuce, peppers, tomatoes and squash Works by contact. Potassium bicarbonate disrupts the potassium ion balance in the fungus cell, causing cell walls to collapse. Powdery mildew Greenhouse cucumber Contact fungicide. See label for details. Pythium root rot and damping off Botrytis grey mold Early blight and gray mold Fusarium, Alternaria, Phomopsis, suppression of Botrytis, and root rots of Phytophthora, Pythium, and Rhizoctonia Tomatoes, leaf lettuce, cucurbits, and peppers Tomatoes and tomato transplants Tomatoes Greenhouse vegetables including lettuce, cucumbers, peppers, tomatoes and vegetable transplants See label for specific usage instructions. Also labeled for greenhouse use on tomato transplants grown for the home consumer market Use in well-ventilated houses only and ventilate two hours after application. Contains a beneficial bacterium. May need to repeat applications. Use as a soil spray or drench.

307 Table Fungicides and Bactericides for Greenhouse Vegetable Production (continued) Fungicide (Trade name, Product Source) Re-entry Interval Streptomyces lydicus (Actinovate, Natural Industries, Inc.) 1 hr. REI Streptomycin sulfate (Agri-mycin 17, Nufarm Americans, Inc.) 12 hr. REI Sulfur (microthiol Disperss, United Phosphorus, Inc.) 24 hr. REI Trichoderma harzianum (PlantShield, Rootshield, Bioworks, Inc.) 0 hr. REI Trichoderma virens GL-21 (formerly known as Gliocladium virens) (SoilGard 12G, Certis USA LLC) 0 hr. REI Triflumizole (Procure, Chemtura) 12 hr. REI Target Diseases Labeled Plants Comments Damping off and root rot, pathogens Pythium, Rhizoctonia, Phytophthora, Verticillium; and foliar diseases including downy and powdery mildew and Alternaria and Botrytis. Greenhouse vegetables and herbs May be applied to soil or foliage through mist systems or sprayer. Bacterial spot Tomatoes and peppers Repeated applications can result in resistant bacteria. Do not apply through any irrigation system. Powdery mildew Pythium, Rhizoctonia, and Fusarium. When applied as a foliar spray, suppresses Botrytis and powdery mildew. Damping off and root rot, pathogens Pythium and Rhizoctonia Powdery mildew Crucifers, cucurbits, peppers and tomatoes and other crops grown in the greenhouse (see label) Greenhouse vegetables such as cucurbits, fruiting vegetables and lettuce. Food crop plants in greenhouse Greenhouse grown cucurbits and transplants, Head and leaf lettuce including Butterhead varieties. Crops grown in greenhouses may be more sensitive to sulfur injury, so try the lowest label rate first. Do not use within two weeks of an oil spray. Contains a beneficial fungus. Avoid applications of fungicides at least one week before or after application. Acts as a preventative. Will not cure diseased plants. Acts as a preventative and will protect noninfected plants. Will not cure already diseased plants. Allow treated soil to incubate for one day prior to planting for best results. Do not use other soil fungicides at time of incorporation. 298

308 Chapter 14 Weed and Algae Control in Commercial Greenhouses Stanton Gill, Extension Specialist Gerald E. Brust, IPM Vegetable Specialist Kate Everts, Vegetable Plant Pathologist Mark VanGessel, Extension Weed Specialist Weed Control Controlling weeds in the greenhouse is important for several reasons. First, weeds serve as a hiding place for several insect and arthropod species, including whiteflies, thrips, aphids, mites, slugs, and snails. Second, weeds can serve as reservoirs for impatiens necrotic spot virus (INSV), tomato spotted wilt virus (TSWV), and several other viruses. Third, weed seeds can end up in pots and containers. Because most growers use sterile soil substrates, weeds are usually not a major problem. Weeds are a major problem on greenhouse floor areas and areas just outside the greenhouse, especially near intake vents. Growers need to check labels for herbicides, since several specifically limit the use when crops are growing in the greenhouse and must be applied to empty growing space. There are not many herbicides available that can be used safely and legally to control weeds in greenhouses. Herbicides are commonly classified by their mechanism of action and use pattern. Preemergence herbicides are applied before weeds emerge and generally provide residual control of weed seedlings for several weeks. There are no preemergence herbicides currently labeled for use in greenhouses. Cultivation and hand pulling are often the few available options. There are two important facts to remember about mechanical cultivation. Hoeing and tilling will control small annual weeds fairly well. However, successive flushes of germinating weeds, stimulated by the cultivation itself, need to be controlled on a two- to three-week cycle. Once residual herbicides are applied and activated with water, they need to be in contact with the germinating weed seedlings to work well. Mechanical cultivation will often destroy this contact. Hand pulling is often an important, if backbreaking, component of a weed management program. It should be considered when no other cultural or herbicide options are available and when weeds are present that will disperse their seed by wind to weed-free areas. Never apply preemergence herbicides in heated or unheated covered houses or greenhouses. Several herbicides that are otherwise safe can volatilize under these conditions and cause injury. Scouting for Weeds in the Greenhouse Scout the outside perimeter of the greenhouse and note if weeds are present near vents or doorways entering the greenhouse. Examine this area during the spring and fall months before a crop is moved into the greenhouse. The easiest nonchemical method to control weeds near the greenhouse is to put a weed barrier fabric in place. Although weeds may germinate through the weed barrier, you can easily hand pull the weeds from the barrier. 299

309 Make sure that substrate used for growing plants is stored in an area protected against weed seeds that may be windblown or washed in by rainfall. Before placing a crop in a substrate, take a representative sample of substrate and fill in a greenhouse flat. Water the substrate and place the flat in the greenhouse for at least a week. If no weeds germinate, then you can probably assume that the substrate is free of weeds. Inspect under the greenhouse benches. If weeds are present, hand pulling is the safest and most effective way to eliminate them. Try to pull weeds when they are still growing vegetatively and before seeds mature; this prevents weed seeds from blowing through the greenhouse. Sometimes bedding plants produce seeds that escape and establish themselves under benches. The plants that result are considered weeds; eliminate them because they can harbor insects, mites, and diseases. Scout under the greenhouse bench on a weekly or bi-weekly basis and eliminate weeds while they re still small. Placing weed barrier cloth under the benches helps prevent weeds from getting established. Remove all pet plants from the greenhouse. Like weeds, these plants can serve as a source of diseases, mites, and insects that can spread to the new greenhouse plants. Weed Control Use Chemicals as a Last Resort Greenhouse growers should be extremely cautious if using herbicides in the greenhouse. Greenhouse and air circulation fans must be off during herbicide application. When applying herbicides, use large droplet, low pressure type nozzles. Table 14.1 Herbicides Labeled for Use in Controlling Weeds in Greenhouses (Only for emerged weeds; i.e. postemergence activity) Chemical Name Brand Name (*restricted use product) Re-entry Interval (hours) Selectivity/ Mode of Action Clethodim Arrow Envoy* Envoy Plus* 24 Selective postemergent; Contact Select Max Clove oil plus citric acid BurnOut II Not specified Non-selective; contact Notes on Use Controls annual and perennial grasses only. Does not control broadleaf weeds or sedges. Do not use in soil beds/benches. No residual activity. Consult label for recommended spray adjuvants. NOTE: Envoy Plus is labeled for ornamentals only. May cause significant injury to flowers of greenhouse grown plants. Select Max and Arrow are labeled for numerous food crops. For ornamental plants only. Controls small annual and perennial broadleaf weeds; poor control of grassy weeds. Thorough coverage is necessary. Rainfall within one hour of application will reduce degree of control. Older, hardier plants may require retreatment. Avoid application to aluminum, tin, iron, or items such as fencing or lawn furniture in order to prevent staining, mottling, or otherwise interfering with finished metal surfaces. 300

310 Table 14.1 Herbicides Labeled for Use in Controlling Weeds in Greenhouses (continued) Chemical Name D-limonene citrus oil extract Diquat (dibromide) Fenoxaprop Fluazifop-Pbutyl Brand Name (*restricted use product) Re-entry Interval (hours) Selectivity/ Mode of Action GreenMatch 4 Non-selective; contact Reward 24 Non-selective postemergent; Contact Acclaim Extra 24 Postemergent; Contact Fusilade II* 12 Selective; postemergent; Systemic Notes on Use OMRI-approved for vegetable and fruit crops. Controls small broadleaf weeds; poor control of grassy weeds. Label does not require adjuvant, but manufacturer recommends use of an adjuvant. Good control of small annual and grassy weeds; large weeds will be injured but may not be killed. Highly toxic do not use on food crops. Use of a nonionic surfactant is recommended. Do not allow contact of spray or drift on desirable foliage. For use on herbaceous perennials only. Controls annual and perennial grassy weeds. Does not control annual bluegrass, broadleaf weeds, sedges, or most perennial grasses. Apply to young (seedling to 3-tiller) actively growing grasses. Flat fan nozzles are recommended. May be tank mixed with other pre- and postemergence herbicides. Thorough spray coverage is essential. Growth inhibition occurs within 48 hours; death within about 14 days. Addition of a surfactant is generally not recommended. Do not use on Salvia, Philodendron, or Pittosporum. Controls annual and most perennial grasses. Does not control broadleaf weeds, sedges, rushes, lilies, and other nongrasses. May be applied over the top or as directed spray in woody and herbaceous ornamentals in containers. Mix with nonionic surfactant (some ready-to-use formulations are available). Thorough coverage is essential; spray to cover but not to runoff. Do not tank mix with other pesticides or fertilizers except as instructed on the label. Growth inhibition occurs within 48 hours; weeds are killed within 2 weeks. 301

311 Table 14.1 Herbicides Labeled for Use in Controlling Weeds in Greenhouses (continued) Chemical Name Glyphosate Glufosinate ammonium Pelargonic acid Sethoxydim Brand Name (*restricted use product) Glyphosate Pro II Round-up Pro Round-up Pro Concentrate Round-up Pro Dry Touchdown* Re-entry Interval (hours) Variable, depending on product Selectivity/ Mode of Action Finale 12 Nonselective postemergent; Systemic Scythe 12 Nonselective postemergent; Contact Sethoxydim G-Pro (1 EC) Notes on Use For use in empty greenhouses only (between crop cycles). Controls broadleaf weeds and small grassy weeds by translocation, killing roots. Field horsetail is not well controlled. See label for recommended spray adjuvants. Do not apply if overhead irrigation will occur within 6 hours. Works in 7-10 days. No residual soil activity. Do not apply to runoff. Turn off fans during application. Treat perennials when in flower and soil moisture level maintains active weed growth. Do not use more than 10.6 quarts of product per acre per year. Keep people and pets off treated areas until dry to prevent transfer to desirable foliage. Maximum application rates up to 2 gal/100 gal water for Roundup Pro and up to 5 qt/100 gal for Touchdown. Apply lower rates to young weeds. For ornamental crops only; not for greenhouses with food-producing crops. Controls broadleaf weeds and small grassy weeds. Air circulation fans must be turned off during application. Use low pressure nozzles that produce larger droplets. Do not use in soil beds/benches. Weed dieback symptoms often noticed within 48 hours. Use of ammonium sulfate may improve control. Controls small broadleaf weeds; poor control of grassy weeds. Older annual and perennial weeds will only be suppressed with top kill. Works best when air temperatures are >80 F. Use low pressure nozzles with larger droplets. Apply in a ventilated area. Do not apply using hose-end sprayers. Possible odor issues. 12 Postemergent Foliar-applied; controls annual and perennial grasses in ornamentals, ground covers, and bedding plants. Does not control annual/ perennial sedges, annual bluegrass, or broadleaf weeds. Spray small, actively growing grasses to wet but not to the point of runoff. Thorough coverage is essential. Do not apply when irrigation will occur within one hour. Caution when using on azalea, potentilla, Japanese privet, and red and white oak. 302

312 Algae Control Algae are common in greenhouses with high moisture levels. They grow on walkways and under benches and can form an impenetrable layer on the surface of pots. Eliminating puddles in the greenhouse will help eliminate algae on the floor and under the bench. Control of algae can also help to reduce shore flies, fungus gnats and moth flies. Manage algae by watering only as needed, avoiding excess puddling on the greenhouse floor, and avoiding watering late in the day. Avoid overwatering to reduce algae growth on pot surfaces. Surfaces with algae can be scrubbed with a stiff-bristle brush. Use chemicals as a last resort to control algae. Table 14.2 Algae Control With Chemicals Common Name Brand Name Formulation/REI Amount to use Registered Use Bromochlorodimethylimidazolidinedione Agribrom Soluble granule Initial application: 10 to 35 ppm maintenance applications: 5 to 10 ppm Clorine dioxide Selectrocide 12G Soluble granule To control: 5 ppm Hydrogen dioxide Zero Tolerance Liquid To inhibit, use 0.25 ppm in continuous treatment. 1:50 for surface applications Can be used on cooling pads, subirrigation mats, floors, and ebb and flow benches and injected into irrigation water. Treat clean surfaces. Not phytotoxic. Caution when using on lipstick vine, ficus, hibiscus, and English ivy. Injects chlorine dioxide into irrigation lines. Ultra low rates irrigate while inhibiting algae; higher rates is a shock treatment to clear lines. Sanitizer for tools, floors, pots, benches, greenhouse structures, watering systems, and cooling pads. Wet all surfaces before treating. Do not mix with pesticides/fertilizers. Can use in chemigation.

313 Table 14.2 Algae Control With Chemicals (continued) Chemical Name Quaternary ammonium chloride salt Sodium carbonate peroxyhydrate Brand Name (*restricted use product) Green-Shield Physan 20 Triathlon GreenClean Pro Granular algicide TerraCyte (34 G)* Re-entry Interval (hours) Liquid 12 Granular 1 Granular 4 Selectivity/Mode of Action 1 teaspoon per gallon of water for greenhouse glass; 1 tablespoon per gallon for walkways. Initial curative application: 10 to 15 lb. per 1000 sf. For prevention/ follow up (weekly or biweekly applications): 5 lb. per 1000 sf Notes on Use Labeled for use on greenhouse glass and walkways. Shock treatment; can be injected into irrigation lines. Surfaces should remain wet for at least 10 minutes. For ornamental crops only. Water activated. Apply over thoroughly watered soil surface. Thoroughly rinse granules off foliage. Use may increase soil ph by 0.5 ph units (makes the soil more alkaline). Incompatible with metal-based fungicides and fertilizers. Do not apply within three days of metal-based applications. 304

314 Part 4 Cultural, and Water, and Fertility Management Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Plant Growth Regulators for Floricultural Crops Water Supply, Irrigation, and Management Irrigation: Too Wet or Too Dry? Precision Irrigation for Nursery and Greenhouse Crops Fertility Management Fertilizer Injection or Fertigation Care and Calibration of Injector Pumps

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316 Chapter 15 Plant Growth Regulators for Floricultural Crops Joyce Latimer, Extension Specialist Brian Whipker, Extension Specialist Optimizing Results Plant growth regulators (PGRs) are chemicals that are designed to affect plant growth and/or development. They are applied for targeted purposes to elicit specific plant responses. Although there is much scientific information on using PGRs in the greenhouse, it is not an exact science. Achieving the best results with PGRs is a combination of art and science science tempered with a lot of trial and error and a good understanding of plant growth and development. For best results, PGRs should be handled as production tools, like water and fertilizer. PGRs should be an integrated part of your crop production cycle. They should not be used as crutches for poor management of other cultural practices. However, PGRs should be used in conjunction with a number of non-chemical control options to manipulate plant growth so well-proportioned, compact plants are produced. Biological Control Selecting shorter growing cultivars is often the first step available to growers for avoiding the occurrence of overgrown plants. While this works well in theory, it may not be commercially practical. Customer demand for specific color or growth form characteristics may limit your choices. However, response to PGRs depends on species and cultivar selection. In general, slow growing or dwarf cultivars will require less PGR than more vigorous cultivars. Some plant species or cultivars are responsive to specific PGRs but not all PGRs. Research your crop, including its responsiveness to PGRs. Environmental and Cultural Control Knowing how the growing environment and cultural practices can affect plant growth will help in managing a crop s growth. There are a number of factors that can be manipulated in the greenhouse or nursery to reduce plant growth: container size, timing of transplant or seeding, irrigation practices, nutrient management, mechanical conditioning, light quality and quantity, pinching, and temperature. How these factors are manipulated will affect whether chemical control is necessary and the amount of PGR required for optimum growth control. Container Size. Root restriction can be used to control plant growth by utilizing a small container or by increasing the number of plants per pot. This method works especially well when other production parameters such as ample light, i.e., wide spacing, and proper nutrition are provided. Plants grown in small pots at close spacing will require more chemical growth regulation for adequate growth control than those receiving ample light. Timing. One of the most effective methods of controlling excessive plant growth is by crop timing. The simple method of staggering the finish time of a crop at 2 to 3 week intervals is very effective with many crops like bedding plants. This ensures that a new supply of plants will be available; thus avoiding the need to hold a crop beyond its market window where it generally becomes leggy. 307

317 Irrigation Practices. A traditional method of controlling plant growth is to withhold water. Drought stress can be used on a number of crops, including impatiens and tomatoes. Allow the plants to wilt slightly between irrigations, but do not allow them to reach the permanent wilting point. Drought stress will lead to shorter plants, but excessive stress or drought stress of sensitive crops may have the undesirable effects of reduced plant quality and delayed flowering. Drought stress also may cause premature bolting of some crops such as ornamental cabbage and kale (cole crops). Growers who tend to run their plants dry will use less PGRs than growers who run their plants wet. The method of irrigation can affect the plant response to PGRs. Plants grown on sub-irrigation trays or water collectors should be treated with lower rates of soil-active PGRs since the overspray from the treatment will be available to the roots during subsequent irrigation events. Nutrient Management. Reducing or withholding fertilizer tends to slow overall plant growth. Limiting the amount of nitrogen to 50 to 100 ppm N will help control growth of many crops like bedding plants. The type of nitrogen supplied can also impact plant growth. Relying on nitrate-nitrogen instead of ammoniacalnitrogen or urea-nitrogen forms (which encourage lush growth) will also help. Phosphorus also promotes plant growth. Plug producers commonly use low phosphorus fertilizers like Cal-Mag or which does not contain phosphorus to help limit stem elongation. As with dry plants, nutrient-deficient plants require less growth regulator for growth control than lush plants. Mechanical Conditioning. Brushing plants is a very effective way of controlling plant height (30% to 50% reductions) of many vegetable transplants or herbs. Currently only one PGR (Sumagic, Valent USA) is labeled for chemical growth control of fruiting vegetable transplants. Brushing involves the movement of a PVC pipe, wooden dowel rod, or burlap bags over the top third of the plant. Research at the University of Georgia suggests that the plants should be brushed daily for about 40 strokes to obtain the greatest effect. The foliage should be dry to avoid damage to the leaves. This method is not effective on plants such as cabbage or broccoli and should not be used if foliar diseases, or, in many cases, flowers, are present. Evaluate the degree of growth regulation provided by brushing before adding a PGR treatment. Also, be aware that the effects of brushing on plant growth dissipate within three to four days after you stop applying the treatment. So, you may want to apply a low rate of a PGR to provide continued growth control during the shipping, handling and retail phases. Pinching. Pinching can be used to improve the shape of the plant, increase branching, and control excessive stretch. However, the labor costs of pinching and the subsequent delay in plant development may not make it an economically feasible option of controlling growth of many crops. Light Quality and Quantity. Higher light quality tends to limit plant elongation, thus resulting in shorter plants. Low light quality caused by late spacing or crowding of the crop or too many hanging baskets overhead can lead to leggy plants and should be avoided. Photoperiod also can be used to control growth of many plants. This practice is widely used with pot chrysanthemums by providing taller cultivars with only one week of long days (LD) to limit vegetative growth when compared to shorter cultivars which receive three weeks of LD to promote growth. Light quantity also affects plant growth. Higher light levels improve plant growth and quality as well as branching. Spacing will often determine the need for, and amount of, additional chemical control necessary for optimum height control under high light levels. Temperatures. Temperature manipulation can be used very effectively to control plant growth. Lower temperatures reduce plant growth. Remember to account for the effects of lower temperatures on the developmental processes of the plant, i.e., lower temperatures may delay flowering so you may need to adjust your crop schedules to hit your market window. Lower rates of PGRs are required for plants grown under lower temperatures. Conversely, higher temperatures enhance plant growth and higher rates of PGRs are necessary for adequate growth regulation. Some growers use differential day/night temperatures (DIF) 308

318 to control growth. In the South and Mid-Atlantic regions, we are typically limited to a DIP in temperatures, where we reduce the pre-dawn temperatures to 5 to 10 F below the night temperature setting and hold it for up to 4 hours. This treatment reduces growth at the time of day that cell elongation is greatest and therefore controls plant height. Obviously, do not use drop the temperature low enough to injure cold sensitive crops. Optimizing plant growth control requires an understanding of the effects of environmental and cultural conditions on plant growth. Experience and in-greenhouse trials will allow you to combine PGRs with a number of non-chemical control options to manipulate plant growth to produce high quality, compact plants. Choosing the Correct PGR The choice of PGRs and their application rates will be affected by the vigor of the cultivars selected and how your crop is grown. Especially with very vigorous plants, higher fertility and irrigation levels will increase the amounts of growth regulator required to prevent excessive growth. Shading, lower light levels or tight plant spacing, especially under higher growing temperatures, also will increase plant stretch and reduce lateral branching. For the highest quality plants, the use of PGRs must be integrated into your production plan. PGRs are most effective when applied at the appropriate times to regulate plant growth or development. In other words, growth retardants cannot shrink an overgrown plant. They must be applied before the plant is overgrown to avoid plant stretch. When planning PGRs in your production schedule, consider what you want to accomplish with the treatment. Do you want to regulate shoot growth of the plant, resulting in a sturdier, more compact plant with improved color? If so, you probably want a growth retardant. Do you want to increase plant branching for enhanced cutting production, or for a more bushy potted plant or hanging basket? If so, you probably want to use a branching agent or chemical pincher. Do you want to enhance flower initiation or synchronize flowering? If so, you probably want to use chlormequat chloride or gibberellic acid. Do you want to remove flowers from stock plants to increase the number of vegetative cuttings? If so, you probably want to use an ethylene-generating compound. Answering these questions will indicate which type of PGR you need to use to accomplish your goal and the most appropriate timing of the application. Then you will need to select a specific PGR in that class, determine the appropriate dosage and the appropriate application method to attain the desired response. Regulating Shoot Growth. Most of the PGRs used in the greenhouse or nursery are used to regulate shoot growth of containerized crops. These PGRs are referred to as growth retardants. Typical growth retardants are daminozide (B-Nine or Dazide), chlormequat chloride (Cycocel or Citadel), ancymidol (A-Rest or Abide), flurprimidol (Topflor), paclobutrazol (Bonzi, Piccolo, Piccolo 10 XC, Paczol, or Downsize) and uniconazole (Sumagic or Concise). Now that most of the PGR chemistries are off patent, there are several options available (Table 15.1). These PGRs control plant height by inhibiting the production of gibberellins, the primary plant hormones responsible for cell elongation. Therefore, these growth retardant effects are primarily seen in stem, petiole and flower stalk tissues. Lesser effects are seen in limiting leaf expansion, resulting in thicker leaves with darker green color. Other benefits of using these PGRs in plant production include improved plant appearance by maintaining plant size and shape in proportion with the pot, and 309

319 increased shipping capacity with the smaller plants. Plant growth retardants also increase the tolerance of plants to the stresses of shipping and handling as well as retail marketing, thereby improving shelf-life and extending plant marketability. Remember growth retardants do not reduce plant size. They limit the plant s growth rate. You must apply the growth retardant prior to the stretch. Look for recommendations on the PGR label for time of application. These recommendations will be given in terms of plant development or plant size as opposed to production time. For example, the uniconazole (Sumagic or Concise) labels specify that pansies should have attained a minimum height of four inches prior to application. The paclobutrazol (Bonzi, Paczol, Piccolo or Piccolo 10 XC) labels state that bedding plant plugs should be treated at the one to two true leaf stage and bedding plants (after transplanting) at two inches of new growth or when the plants reach marketable size. Generally, growth retarding PGRs should be applied just prior to rapid shoot growth. This is generally one to two weeks after transplanting a plug, after the roots are established and as the plant resumes active growth; on pinched plants, it is after the new shoots are visible and starting to elongate. This is where the art of plant growth regulation is most important. You must learn how your crop grows and when to intervene to obtain the desired results. Remember to note details of crop development in your records of PGR treatments. For example, due to the weather conditions, next year you may need to treat at seven days after transplanting instead of at the ten days after transplanting that you used this year. You must gauge when rapid elongation will likely occur and treat to counter it. Many growers use multiple applications of growth retardants to better control plant growth. A single application at a high rate early in the plant production cycle may be excessive if growing conditions are not as good as expected. An early application at a lower rate provides more flexibility, but the tradeoff is the additional labor involved with a second application if it becomes necessary. Some growers improve crop uniformity by using multiple applications of lower rates to affect small corrections in plant growth. Be aware that excessive rates of many of these PGRs can cause persistent growth reductions in the flat or even in the landscape. It is always a good idea to evaluate the long-term effects of your treatments by growing some out for yourself and talking with your customers. Be careful to avoid late applications, especially of paclobutrazol or uniconazole as they may delay flower opening on bedding plants. However, low dose drench applications of paclobutrazol have provided excellent control of poinsettia height very late in the production cycle without causing the reduction in bract size accompanying late spray applications. Learn the art of using PGRs for plant growth regulation. Daminozide (B-Nine or Dazide; Re-entry Interval (REI) = 24 hr) was one of the first PGRs labeled for use in the floriculture industry and is still widely used. In general, it is not phytotoxic and has a short-term effect that seldom results in over-stunting of treated plants. The low activity of daminozide and its lack of soil activity make it easier to get consistent, predictable responses than with the newer, more potent PGR chemistries. Plants should be well-irrigated prior to treatment but foliage should be dry at the time of treatment. Do not irrigate overhead for 18 to 24 hours after treatment. The low activity also means that daminozide must be applied more frequently to maintain control over vigorous crops. Generally, foliar sprays of 2500 to 5000 ppm are applied every 10 to 14 days as necessary. Daminozide is labeled for use on containerized or bed-grown crops in the greenhouse, and on containerized plants grown outdoors under nursery conditions. Frequency of application may need to be increased to weekly for more vigorous cultivars grown outdoors. Chlormequat Chloride (Cycocel or Citadel; REI = 12 hr) is another PGR with a long history in floriculture. Note that the product use labels for these chlormequat chloride products vary in application limits. See the label for your product for the specific rates and sites of application (Table 15.1). Chlormequat chloride is generally applied as a foliar spray at 200 to 3000 ppm with a maximum of three to six applications per 310

320 crop cycle depending on which product you use. Rates above 1500 ppm often cause chlorosis on young treated leaves of floricultural crops. Chlormequat chloride also promotes earlier flowering and greater flower numbers on Hibiscus and geranium (Pelargonium). Chlormequat chloride is also labeled for drench applications at rates of 2000 to 4000 ppm when applied inside a greenhouse depending on the specific product label (Table 15.1). Only Cycocel is labeled for use on containerized plants in the outdoor nursery where it may be applied at a maximum spray rate of 3000 ppm up to three times in any crop production cycle. This limit includes any applications of Cycocel combined with daminozide. Drench applications of Cycocel are not permitted in the outdoor nursery, even on containerized plants. Read the pesticide label for your product. It is the law for application sites and rates. Chlormequat chloride is not labeled for application through the irrigation system. A Daminozide/Chlormequat Chloride Tank Mix has more PGR activity than either daminozide or chlormequat chloride alone and generally causes less phytotoxicity than chlormequat chloride applied by itself. Both the daminozide and chlormequat chloride labels have approved tank mix instructions. This combination provides activity that ranges from low (800 ppm daminozide plus 1000 ppm chlormequat chloride) to very high (5000 ppm daminozide plus 1500 ppm chlormequat chloride). This tank mix has been tested on a wide variety of perennials. For example, three-lobed coneflower (Rudbeckia triloba) was very responsive to B-Nine applied twice at 5000 ppm, but not responsive to Cycocel at rates up to 4000 ppm. However, a tank mix of 5000 ppm B-Nine with increasing rates of Cycocel resulted in height control similar to the B-Nine treatments with a single application. Although the rate of daminozide is usually adjusted to increase or decrease activity, changing the chlormequat chloride rate also affects activity. Single applications of the tank mix are frequently more effective than multiple applications of daminozide alone. However, multiple applications of the tank mix may be required for the more vigorous crops. Ancymidol (A-Rest or Abide; REI = 12 hr) is a more active compound than daminozide or chlormequat chloride. Ancymidol is active as a spray or a drench so application volume affects plant response. In addition, ancymidol is labeled for chemigation, i.e., distribution through the irrigation system via flood, sprinkler or drip systems. Follow all label directions. A-Rest is labeled for use as a spray or drench on containerized plants in greenhouses, nurseries, shadehouses and interiorscapes. Abide is not labeled for spray applications in shadehouses or nurseries but drench applications can be made indoors and outdoors. Ancymidol is widely used for treatment of plants in the plug stage. Its relatively high activity and toning ability produce excellent plugs. Many growers consider ancymidol to be the product of choice for pansy production, both for plugs and finished plants. Rates vary with cultivar or series. For example, the Delta series is more responsive to PGRs than the Sky/Skyline series. Flurprimidol (Topflor; REI = 12 hr) is similar in chemistry to ancymidol but much more potent. Its activity is similar to that of the triazoles. Many floricultural crops are responsive to flurprimidol. With spray applications, Topflor rates are similar to those used with paclobutrazol. However, in substrate applications, its activity is more similar to that of uniconazole. It is labeled for use as a spray, drench, or chemigation on containerized ornamental plants grown in nurseries, greenhouses, and shadehouses. Topflor is only recommended for a few bedding plant plugs and should never be used on the plugs of sensitive crops like begonia, pansy, salvia or vinca. Topflor is very active on most bulb crops like tulips, Oriental lilies, callas, caladiums, and hyacinths, where it is applied as a drench when the new growth is about one-inch tall. A more recent formulation is Topflor G, a granular formulation that is applied to the substrate surface of ornamentals grown in containers. The triazole class of PGRs includes Paclobutrazol (Bonzi, Piccolo, Piccolo 10 XC, Paczol, or Downsize; REI = 12 hr) and Uniconazole (Sumagic or Concise; REI = 12 hr). These compounds are much more active 311

321 than most of the previous compounds. Uniconazole is more potent than paclobutrazol. As mentioned above, the activity of flurprimidol (Topflor) is between these two triazoles depending on application method. These PGRs are rapidly absorbed by plant stems and petioles or through the roots. Excess spray dripping off treated plants acts as a drench to the substrate, increasing the activity of the treatment. For foliar sprays of triazoles, uniform application of a consistent volume per unit area is critical to uniform and consistent crop response. Both compounds (see Table 15.1) are labeled for application to the substrate surface as a substrate spray prior to planting plugs in the filled containers. The PGR moves into the substrate with subsequent irrigations and effectively behaves as a drench. Take care with applications to sensitive plants. In some cases, excessive stunting can be persistent. Growth of velvet sage (Salvia leucantha) was excessively reduced by 45 or 60 ppm Sumagic in the greenhouse. Furthermore, 60 ppm Sumagic caused in a significant delay in landscape growth of the Salvia. These compounds must be used carefully and appropriately. Especially when working with the triazoles, thoroughly test your application methods and rates on a small number of plants before treating your entire crop. Avoid late applications of the triazoles. They should be applied prior to flower initiation when possible. Paclobutrazol has a broad label for ornamentals that includes use on greenhouse or outdoor-grown containerized crops. See Table 15.1 for label restrictions for the different products. All of the paclobutrazol products are labeled for application through the irrigation system, including ebb/flow or flooded floor systems. Do not use paclobutrazol on annual vinca (periwinkle) as it causes spotting or on fibrous begonias which exhibit severe stunting with exposure to paclobutrazol. To establish rates for plants not listed on the product label, treat a small number of plants with 30 ppm as a foliar spray or 1 ppm as a drench. In many cases, multiple treatments with lower rates have been more effective, with less chance of over-stunting, than a single application at a higher rate. The Piccolo 10 XC formulation is 10x more concentrated than the other formulations and is also a clear formulation which tends to stay in solution more uniformly than the others. The higher concentration combined with smaller packaging is preferred by many growers. Uniconazole also has a broad label for ornamentals, but its use is limited to containerized plants grown in greenhouses, overwintering structures, shadehouses, or lathhouses. It is not labeled for outdoor nursery use. Uniconazole also is not labeled for application through any irrigation system. Uniconazole has been very effective on a large number of floricultural crops. As with paclobutrazol, avoid using on fibrous begonias. Since it is very potent, pay special attention to proper mixing, uniform application and proper volumes. Use caution in the higher rates or on more sensitive species since uniconazole effects can be persistent in the landscape. NOTE: Ancymidol, flurprimidol, paclobutrazol and uniconazole are persistent on plastic surfaces and in soil. Do not reuse flats, pots or soil from treated plants, especially for plug production of sensitive crops. Enhancing Lateral Branching. Another group of PGRs used in floricultural crops are those that enhance branching, including ethephon (Collate or Florel), BA (benzyladenine, Configure), dikegulac sodium (Augeo), and methyl esters (Off-Shoot-O) (Table 15.2). These PGRs are frequently called chemical pinchers because they generally inhibit the growth of the terminal shoots or enhance the growth of lateral buds, thereby increasing the development of lateral branches. They can be used to replace mechanical pinching of many crops like Vinca vine, Verbena, Lantana, and English ivy (Hedera). Ethephon (Collate or Florel Brand Pistill (Florel); REI = 48 hr) is a compound that breaks down within plant tissue after application to release ethylene, a natural plant hormone. As with ethylene, its effects can vary depending upon the species and the stage of growth at time of application. Ethephon products have 312

322 a broad use label for increasing lateral branching of floricultural crops. Ethephon is commonly used on zonal and ivy geraniums and poinsettia to increase branching and also inhibits internode elongation of many plants. In our studies, ethephon controlled runner elongation of clump verbena (Verbena Homestead Purple ) and increased inflorescence numbers of sage (Salvia May Night ) and yarrow (Achillea Coronation Gold ). You may need to consider combinations of PGRs. For example, if you apply ethephon to enhance the branch development of Wave petunias in a hanging basket, you may still need to follow up with a treatment of a plant growth retardant to control the elongation of those new laterals. Ethephon should be applied to actively growing plants prior to flower development. If flowers are present at the time of application, they are likely to abort. Ethephon may delay flowering about one to two weeks, particularly if applied close to the time of flower initiation. Ethephon should not be applied to plants that are heat or drought stressed. Ethephon has typically been applied as a foliar spray and the ph of the water used for the spray solution can be important. If the ph is too high, the ethephon will convert to ethylene before it gets to the plant and activity will be reduced. The ethephon formulations contain sufficient acidifiers and buffers to maintain a ph of 5.0 or lower when mixed with most greenhouse water supplies. In general, water that has sufficient quality for irrigation of greenhouse crops (moderate ph and alkalinity) is suitable for mixing ethephon. However, if you are acidifying your water prior to irrigation, use the acidified water for mixing the ethephon as well. The solution should be applied within 4 hours of mixing. More recent research has identified soil activity and growth control with drench applications of ethephon. Collate, a 21.7% formulation of ethephon, is relatively new to the market and has a label amendment pending for drench and liner soak applications to floriculture crops in the greenhouse. Benzyladenine (6-BA, Configure; REI = 12 hr). Configure is a synthetic cytokinin (6-benzyladenine) which is a plant hormone that stimulates lateral branching. It is a relatively inexpensive PGR and enhances branching of a wide variety of floricultural crops. Configure stimulates, but does not cause, an increase in branching. Therefore, timing of the application is critical to a good branching response. Again, read the label for details of when to apply for optimum response. BA has a short period of activity and has no residual in the plant. So, multiple applications are most effective with many crops. Furthermore, it is not well translocated in the plant so thorough coverage is required. Depending on the timing of the Configure application, BA increases branching of the phyllocades or, when applied during floral initiation, increases the number of flower buds breaking on Christmas cactus. Configure at 500 to 3000 ppm increased basal branching of Hosta and at lower rates, 300 to 600 ppm, increased basal branching of Echinacea. Further screening trials with other annuals and herbaceous perennials have identified a large number of crops with increased basal or lateral branching in response to Configure. We have found a few incidences of phytotoxicity on herbaceous perennials with Configure application at 600 ppm, including asters and cosmos. In addition, pansy and exacum are very sensitive to spray applications of Configure with long-lasting leaf yellowing even at low rates, 50 to 100 ppm. Much of our research has focused on application of branching agents during liner production. Early application to liners as soon as rooting has occurred and plants are removed from mist has been successful in increasing the number of shoots and branches with many herbaceous perennials. So, we generally recommend two to three applications at low to medium rates at 2-week intervals. Although the primary objective with Configure is to increase branching, it has resulted in growth control in some crops. However, if additional growth control is necessary, we have found that growth retardants may be used immediately following the Configure treatment without reducing the branching response. Dikegulac sodium (Augeo; REI = 4 hr) is a compound that interferes with terminal growth by interrupting cell wall integrity in meristem areas. By primarily inhibiting terminals, apical dominance is reduced which 313

323 enhances the production of lateral branches. This mode of action may cause a slight delay in the resumption of plant growth and may result in some leaf yellowing. Take care not to overwater or over-fertilize during this period. Augeo has a broad use label on greenhouse ornamentals as well as container-grown and landscape ornamentals and trees and a very short REI. Dikegulac sodium should be applied early in the production cycle to actively growing plants with at least two nodes to provide sufficient lateral development. Early application allows for development of the branch structure and for later leaf development to cover any remaining yellow leaves. In addition to creating a fuller plant, enhancing the number of laterals in a pot generally results in a shorter overall height of the plant due to the greater distribution of resources. Responses are very species-specific so test several rates under your growing conditions. Generally rates about 400 ppm have been effective on herbaceous materials and higher rates, 800 to 1600 ppm on woody ornamentals. Enhancing Plant Flowering. Plant growth regulators can be used to enhance flowering. To improve flowering, Florgib, ProGibb T&O or GA 3 4%, which contain the growth promoter gibberellic acid (GA 3 ), can be used to substitute for all or part of the chilling requirement of some woody and herbaceous ornamentals typically forced in the greenhouse, including azalea for florist crops and Aster for cut flowers. These compounds also can improve flowering and/or bloom size of camellia and baby s breath (Gypsophila), promote earlier flowering and increased yield of statice (Limonium) and induce of flowering of Spathiphyllum. Gibberellic acid also is used to promote growth and increase stem length of other cut flowers like stock (Matthiola), Delphinium, and Sweet William (Dianthus). See product labels for specific uses and recommended rates. Again, timing is critical since late applications, or excessive rates, may cause excessive plant stretching resulting in weak, spindly stems. Chlormequat chloride (a plant growth retardant) used to control stem height of hibiscus and geranium also improves early flowering of these crops. Removal of Flowers. Flower removal is especially desirable for stock plants maintained for cuttings of vegetatively propagated ornamentals, like Verbena or Lantana. Ethephon is the primary compound used for flower removal. Once ethephon is absorbed by the plant it is converted to gaseous ethylene, a natural plant hormone effective in many plant processes. Ethylene is the primary hormone responsible for flower senescence and fruit ripening. It is the postharvest hormone. With proper rates and timing, it will remove unwanted flowers from stock plants, cuttings, or plugs. Flower removal diverts more energy into vegetative growth and increases the number of laterals available for cuttings on stock plants, promotes increased branching of plugs and finished plants which increases fullness in the container. Since initiation and development of flowers requires time, ethephon should not be used on most crops within six to eight weeks of marketing. Other PGR Uses. Another specific application of the gibberellin and cytokinin products (Fascination or Fresco) is the reduction of lower leaf yellowing on Easter, Oriental, and LA hybrid lilies. See the label for detailed instructions. These products also may be used to increase bract expansion in poinsettias. Fascination, ProGibb T&O and GA 3 4% are labeled to promote the growth of plants that have been overregulated by plant growth retardants. These PGRs are very potent growth promoters. Start with low rates, 1 to 3 ppm, and apply at 5 day intervals as necessary. Read the Label! Plant growth regulators are classified as pesticides. Therefore, they are subject to all of the same USDA recordkeeping and Worker Protection Standard (WPS) rules as all of your other pesticides. Their use is governed by the manufacturer s label as with other pesticides. The label not only contains information on restrictions, but also much information on how to use the product effectively. Before going to the time and expense of applying PGRs to your crop, answer these questions: 314

324 Is the chemical labeled for the crop you wish to treat? Most of the PGR labels have undergone revisions that apply to a broad range of similar crops not specifically listed on the label, with the user taking responsibility for determining appropriate rates. This provides label permission to use the compound on these crops without the manufacturer accepting the responsibility for the rate selection. Is the chemical labeled for the area you wish to treat? Many of the PGRs are only labeled for use inside a greenhouse or other growing structure. Are there any potential side effects such as phytotoxicity? Note that you may need to look elsewhere for this information for your specific crop. Are there label warnings regarding the PGR s effect on plant flowering? For example, many branching enhancers delay flowering. Ethephon products cause flower bud abscission prior to enhancing branching, therefore, is not recommended within six to eight weeks of marketing. Side effects are frequently affected by the timing of the application; e.g., late applications of growth retardants may delay flowering. Always follow the label for mixing and application instructions. Many of these products require a thorough shaking before dispensing. For best results use only clean equipment that is dedicated to PGRs. Do not use sprayers that may contain other pesticide residues. In general, PGR labels restrict the addition of wetting agents and tank mixing with other pesticides or fertilizers. See the label for specific applications that recommend additional adjuvants. Follow label directions exactly in mixing PGR solutions and apply them on the same day as they are prepared. Store PGRs tightly sealed in their original containers in a cool, dry, dark place. Application Guidelines Spray Applications. Plants to be treated with PGRs should be healthy, turgid and unstressed never wilted. The label will identify the target tissue for that PGR. For example, daminozide is only effective as a foliar spray whereas paclobutrazol and uniconazole sprays must reach the stems. When making spray applications, look at the growth and development of the plant to see that there is sufficient development to make the treatment effective and to accomplish your goal. Generally, there should be sufficient foliage or stems to absorb the PGR. Uptake and effectiveness of a PGR also depend on selecting the application technique that will ensure proper coverage of the target tissue. Daminozide is not soil active. A foliar spray application, wetting most of the foliage, provides a uniform reduction in growth. Leaf surfaces should be dry for foliar applications and the best uptake of PGRs from spray applications will occur under low stress, low drying conditions. This is more critical for daminozide and ethephon than for some of the newer chemistries like the triazoles. Overhead irrigation after treatment with daminozide or ethephon should be delayed for 18 to 24 hours to avoid washing the material off of the leaves. The triazoles, paclobutrazol and uniconazole, are absorbed primarily by stem tissue and then translocated upwards in the plant. Therefore, consistent and complete coverage of the stems is necessary for uniform effects. In other words, if the stem of one lateral receives an inadequate amount of spray, it will grow faster than the others, resulting in a poorly shaped plant, most noticeable in potted crops like poinsettia or chrysanthemum. Ancymidol and flurprimidol are taken up by both foliage and stems. In addition, all four of these compounds are very soil active which means they may be adsorbed to particles in the substrate and become available to the plant through root uptake. Therefore, drenching is a very effective application method for these chemicals in crops where it is economically feasible (see How to Apply Drenches below). 315

325 The label will provide a recommended application volume for sprays, especially for chemicals that are soil active. All foliar applications of PGRs should be applied on an area basis, i.e., uniformly spray the area where the plants are located with the recommended volume of solution. Do NOT spray individual plants or spray to reach a subjective target like spray to glistening. Since every applicator will have a slightly different definition of these goals, there will be no way of recommending appropriate rates or obtaining predictable results. For soil active PGRs, dosage is dependant on both concentration of the solution and the volume of that solution applied in the treated area. Therefore, to improve predictability, the labelrecommended spray application rates are generally set at 2 qt. finished spray per 100 sq. ft., which is sufficient to cover the plant and permit a small amount of runoff onto the medium. It also is considered to be a comfortable walking pace for applicators with hand-held sprayers. This is the same application volume recommended for daminozide which is not soil-active. With the soil active PGRs, precautions should be taken to avoid over-application with sprays. Spray applications require more attention to detail because overspray material lands or drips onto the medium. The overspray from a 2 qt. per 100 sq. ft. application is a part of the recommended dosage. However, if your application volume exceeds that recommendation, then your application dosage also exceeds the recommendation. Recognizing that stem coverage is necessary for the triazoles, you may need to apply a higher than recommended volume to large or dense plants to obtain adequate coverage. In fact, the paclobutrazol label recommends a spray volume of 3 qt. per 100 sq. ft. for larger plants with a well developed canopy. Adjust the concentration you apply accordingly. This suggests the importance of record-keeping (see below). Always consider the rates presented in Table 15.3, on PGR product labels, or from any other resource, to be a guideline to assist you in developing your own rates based on your growing conditions and application methods. The relationship of rate and volume can be exploited when treating multiple crops with different PGR needs. With a single solution of PGR in the spray tank, you can apply the label recommended volume to attain your basic application dosage or you can apply additional volume to crops that need additional growth regulation to attain a higher dosage. Application volume is another tool that you can use to maximize your efforts and reduce time mixing or reloading higher concentrations of PGR solutions. Spray Equipment. To assure proper spray volumes, your compressed air sprayer should be equipped with a pressure gauge and regulator and you should consistently use the same nozzle for all PGR applications. Your sprayer should be calibrated by determining the output of the chemical with the selected nozzle at the selected pressure within a specified time period. Using this information, you can apply a known amount of material to a known area. Spray droplet size also affects response with smaller droplet sizes providing better coverage, but only up to a point. Mist or fog type applicators do NOT provide adequate volume for coverage of plant stems and the medium, and therefore, have not been effective when used with compounds like paclobutrazol and uniconazole. PGR applicators should be trained to uniformly apply a given amount of clear water in the greenhouse before they make PGR applications. Uniformity of the application is critical to the uniformity of the crop response. Applying Drenches. Although drench application has several advantages over sprays, traditional drenches are seldom used on perennials due the higher application costs of handling individual pots. Drenches generally have less negative effects on flowering or flower size, and tend to provide longer lasting growth regulation than sprays. Drenches are easier to apply uniformly than sprays because the drench volume is easily measured, and when applied to moist substrate, it is easy to obtain good distribution of the PGR in the substrate. Therefore, the resulting growth regulation is frequently more uniform. The product label specifies the recommended volumes for drench applications to different size pots or types of substrate. In general, 316

326 4 fl. oz. of drench solution is applied to a six-inch azalea pot, and that volume is adjusted up or down with pot size to obtain a volume where about 10% of the solution runs out the bottom of the pot when the substrate is moist. Remember that the amount of active ingredient applied to plants depends on both the concentration (ppm) of the solution and the volume applied. Read the label. Below is a general table of volume recommendations for drench applications: Pot diameter Drench volume Drench volume (inches) (fl. oz. per pot) (ml per pot) Alternative methods of applying PGRs directly to the substrate have been developed and are described on the label. For example, ancymidol, flurprimidol, and paclobutrazol are labeled for application through the irrigation system ( chemigation ). These are generally labeled for flood (sub-irrigation), drip irrigation and overhead sprinkler systems. Again, rates vary with the volumes used and method of application. Paclobutrazol applied once by sub-irrigation requires 50% to 75% of the amount of paclobutrazol that is applied in a typical drench application. Pressure compensated drippers are recommended for use with PGRs to more accurately regulate the volume of solution applied to each pot. Read and exactly follow the label for chemigation applications, especially with regard to safety of municipal water supplies. Three other methods of providing a drench type application of soil-active PGRs on a more economical scale are being used by growers. One is substrate surface application sprays. These are spray applications made to the surface of the substrate of filled flats or pots. The treatment is applied at normal to high spray volumes but since it is applied to the substrate surface it is activated by irrigation and is available to the plant in the root zone. Both paclobutrazol and uniconazole are labeled for this method of application. Rates are lower than used for sprays, but higher than used for drench applications. A second method is called sprenches which is a high volume foliar spray that results in additional runoff into the substrate, providing a drench effect. Rates are lower than for recommended for spray rates. A third technique is called watering in is a type of chemigation where the PGR is injected into the irrigation water and applied at each irrigation at very low rates of active ingredient. Only PGRs labeled for chemigation can be used for watering-in. All of these application methods use the relationship between rate and volume to provide the desired control. Again, you must develop techniques that fit your production methods and your growth management preferences. Liner soaks or drenches are another specialized way to use soil active growth retardants. Although many of the soil active PGRs have been tested, only Paczol and Piccolo (paclobutrazols) are labeled for this application (Table 15.1). The root system of rooted liners or plugs is soaked in a solution of the PGR (or they may be thoroughly drenched in the plug tray). Extensive work has been conducted at the University of Florida on this application method: Liners should be dry which is defined as the root ball being ready for irrigation, but not under drought stress. Time in the solution is not critical; 30 sec to 2 minutes is sufficient for saturation of the rootball. Liners may be planted after 1 hour or held up to 10 days without loss of PGR effect. There is no loss of effectiveness of the PGR soak solution during treatment. 317

327 Advantages of the liner soak include early control of very vigorous crops and flexibility of the treatment with respect to not having to handle plants during the restricted entry interval (REI). The liner soak is especially useful in combination plantings where the more vigorous plants can be treated prior to planting without reducing the growth of the slower plants in the group. The liner soak rates should be selected to provide early control of plant growth. Additional applications can be made as necessary for longer term crops. Be Aware of Bark. For many years, the adage in PGR drenches has been Bark ties up soil-active PGRs. However, new research shows that this is not necessarily true. As long as the bark is properly aged before the substrate is mixed, it has little effect on the availability of these soil active PGRs to the plant roots. Again, you must identify PGRs and rates that work with your production system. Growing Conditions. Look also for label recommendations on time of day or condition of the plant for optimum treatment response. Generally, a healthy, unstressed plant growing under low evaporative conditions, e.g., early in the morning or late in the afternoon, is most responsive to treatment. To maximize uptake, the chemical must remain in contact with the leaf long enough to be absorbed. This time varies for the different PGRs, but generally foliar uptake is enhanced with slower drying conditions which in turn increases the effectiveness of the treatment. This is especially important with foliar uptake of PGRs like daminozide, chlormequat chloride, BA or ethephon. Plants treated with daminozide or ethephon should not be overhead irrigated for at least 18 to 24 hours after treatment, and plants treated with Augeo should not be irrigated for 6 hours. However, plants treated with flurprimidol, paclobutrazol or uniconazole may be overhead irrigated one hour after treatment. Read the label for any warnings on how irrigation or environmental conditions will affect plant response to the PGR treatment. Recordkeeping Keeping notes on your application methods and the results of your PGR treatments will allow you to improve the consistency of your own application methods and establish rates and volumes appropriate your production system. Note the concentration and the volume applied, the stage of development of the crop (number of leaves, approximate height, presence of flowers), and the environmental conditions under which the PGR was applied. It is always recommended to keep a few untreated plants for comparison, especially if you are new to using PGRs. Summary The degree of growth regulation caused by PGRs is impacted by all other phases of plant culture. Remember that you have to fit PGRs into your own production program. Plan ahead to achieve the best results from PGRs; do not use them as an afterthought when the plants are out of control. You cannot shrink an overgrown plant! The multitude of variations possible in application methods, cultivar and species grown, and growing conditions make it impossible to recommend specific rates for all operations. Use the product labels and Table 15.3 as a resource for the use of PGRs on a variety of crops. In the Mid-Atlantic and South, use the lower of suggested effective rates for starting your own trials. There are a couple of general rules for using rate recommendations from other sources: 1) Southern growers use higher rates and more frequent applications than Northern growers. Rates for Virginia/Maryland tend be closer to the Southern rates. 2) Outdoor applications usually require higher rates or more frequent applications than for plants grown under cover. 318

328 Always consider any rate recommendation as a starting point for your own trials and keep records of your successes and failures with PGRs. Whenever you treat your crop, hold back a few untreated plants so that you can judge the effectiveness of your treatment. Remember that methods of application have significant effects on results. Develop your own program, then test and refine it. Watch for PGR compounds new to the floriculture market and for expanded labeling of current products as we develop more guidelines for their use on perennials. Recommended Resources PGR MixMaster your plant growth regulator solution calculator For a ready resource on preparing PGR solutions, download the PGR MixMaster app for your mobile device: This calculator was developed by floriculture specialists from North Carolina State University and the University of New Hampshire. It allows you to enter your own PGR costs and calculate solutions based on the rate desired and the amount of area to be treated. The calculator includes information on both spray and drench applications. It not only gives you the amount of PGR to mix per gallon or liter of water, but also provides the cost of the application based on the area or number of containers treated. 319

329 Table 15.1 Plant Growth Regulators Used To Reduce Plant Height Common Name/Trade Name(s) Ancymidol A-Rest (SePRO Corp.) Abide (Fine Americas, Inc.) Application Methods Foliar spray Bulb dip Drench Chemigation Injection Comments Broad spectrum label. Very safe. Very active on many bedding plants (except geraniums and impatiens); commonly used on plugs. A-Rest labeled for use as spray or drench on containerized ornamentals grown in nurseries, greenhouses, shadehouses and interiorscapes. Concerns Relatively expensive for many crops, but used extensively on plugs. Maximum spray rate is 132 ppm. Do not add wetting agent. Do not reuse pots, trays or media previously treated with ancymidol. Chlormequat chloride Cycocel (OHP) Citadel (Fine Americas, Inc.) Daminozide B-Nine 85WSG (OHP, Inc.) Dazide 85WSG (Fine Americas, Inc.) Foliar spray Drench Foliar spray Cutting dip Abide label prohibits spray applications in shadehouses or nurseries. Drench applications can be made indoors or outdoors. Standard for geraniums, hibiscus, and poinsettias; enhances flowering of geranium and hibiscus. Label allows use on a broad spectrum of greenhouse crops. Activity is low; multiple applications generally required. See label for maximum rates and number of applications allowed for specific crops. Increased activity when tank mixed with daminozide. Only Cycocel is labeled for use on containerized plants in shadehouses and outdoor nurseries (max 3000 ppm 3 times in any crop cycle). Apply uniformly to foliage. No soil activity. Effective on a broad list of species, but low level activity and short residual; multiple applications generally required. Increased activity when tank mixed with chlormequat chloride. Follow all label directions for all chemigation uses (A-Rest not labeled for chemigation in CA). Causes discoloration of leaves especially with rates above 1500 ppm; phytotoxicity reduced in tank mix with daminozide. Less effective under high temperature conditions. Not labeled for chemigation. See label for AZ restrictions Safe. Few incidences of phytotoxicity or overstunting. Do not overhead irrigate within 24 hrs. after treatment. B-Nine sprays are labeled for use on ornamentals grown in commercial or research greenhouses, shadehouses and nurseries. In production areas not under cover, use is restricted to containerized ornamentals. See label for AZ restriction Dazide sprays labeled for containergrown greenhouse plants. 320

330 Table 15.1 Plant Growth Regulators Used To Reduce Plant Height (continued) Common Name/Trade Name(s) Flurprimidol Topflor (SePRO Corp.) Topflor G (SePRO Corp.) Application Methods Spray Drench Chemigation Subirrigation Comments Labeled for use as spray or drench on containerized ornamental plants grown in nurseries, greenhouses, and shadehouses (greenhouses only in New York). Topflor G is a granular formulation for topical application on ornamental plants grown in containers (greenhouse only in NY). Concerns Do not use on plugs of begonia, pansy, salvia or vinca. Do not use wetting agents or reuse pots, trays or media previously treated with flurprimidol. Follow all label directions for all chemigation uses (chemigation not permitted in NY or CA). Paclobutrazol Bonzi (Syngenta Crop Protection) Piccolo (Fine Americas, Inc.) Paczol (OHP, Inc.) Downsize (Greenleaf Chemical, LLC) Spray Media spray (Paczol only) Drench Bulb dip Liner dip (Piccolo only) Chemigation Subirrigation Labeled for use as spray or drench on containerized ornamental plants grown in nurseries, greenhouses, shadehouses and interiorscapes. Apply uniformly to cover stems (not absorbed by leaves). Much more active than above PGRs; measure accurately. Spray procedure and uniformity greatly affects results. Very soil active as a drench. Piccolo or Piccolo 10 XC sprays are limited to enclosed areas (greenhouses) to eliminate drift. Piccolo 10 XC is a 10x concentrate (4% a.i.)., clear formulation which is reported to stay in solution more uniformly for use on containerized ornamentals grown in greenhouses and nurseries. Downsize is labeled only for drench applications on ornamental plants grown indoors or outdoors, manually or through chemigation. See ground and surface water warnings on Topflor G label before use. Spray volume critical to establishing rates due to drench effect of runoff. Use higher rates under high temperature conditions. Late applications can reduce flowering. Phytotoxicity includes overstunting and may cause black spots on annual vinca. Avoid drift onto nontarget plants. Agitate spray solution often for uniform concentration. Do not reuse pots, trays or substrate previously treated with paclobutrazol. Follow all label directions for all chemigation uses. 321

331 Table 15.1 Plant Growth Regulators Used To Reduce Plant Height (continued) Common Name/Trade Name(s) Uniconazole Sumagic (Nufarm Americans, Inc./Valent USA Corp.) Concise (Fine Americas, Inc.) Application Methods Spray Substrate spray Drench Bulb dip Liner dip (unrooted mums) Comments Labeled for use as spray or drench on containerized ornamental plants grown in greenhouses, lathhouses, and shadehouses. Spray procedure and uniformity greatly affects results. Apply uniformly to cover stems (not absorbed by leaves). Very soil active as a drench. Sumagic also is labeled for greenhouse grown fruiting vegetable transplants (see Supplemental Label). Concerns Spray volume critical to establishing rates due to drench effect of runoff. Use higher rates under high temperature conditions. Do not add wetting agents. Late applications can reduce flowering. Phytotoxicity includes overstunting. Avoid drift onto nontarget plants. High leaching potential. Do not apply to pots on dirt floors. Do not reuse pots, trays or substrate previously treated with uniconazole. Not labeled for chemigation. 322

332 Table 15.2 Other Plant Growth Regulators Used In The Production of Floricultural Crops Common Name/Trade Name(s) Ethephon Collate (Fine Americas, Inc.) Florel Brand Pistill (Monterey Chemical Co.) Benzyladenine/ GA 4+7 Fascination (Nufarm Americas, Inc./ Valent USA) Fresco (Fine Americas, Inc.) Gibberellic acid (GA 3 ) ProGibb T&O (Nufarm Americas, Inc./ Valent USA) Florgib 4L (Fine Americas, Inc.) GA 3 4% (Greenleaf Chemical, LLC) Application Methods Foliar spray Drench (Collate label pending) Liner soak (Collate label pending) Foliar spray Foliar Spray Comments Collate is 21.7% ethephon and Florel is 4% ethephon. Labeled for greenhouse, nursery and field grown ornamentals. Promotes lateral branching, thereby reducing stem elongation. Also aborts flowers; improves stock plant branching and cutting yield. Use early in crop cycle to increase branching and remove early flowers (6-8 wk before market). Reduces height and stem topple of potted daffodils and hyacinths. Growth promoter and labeled for prevention of leaf yellowing and to delay flower senescence of Easter, oriental, and Lilium longiflorum x asiatic (LA) hybrid lilies; promotion of stem length, leaf and bract size in poinsettia; and growth promotion to overcome growth retardant effects on containerized and field grown ornamentals. Growth promoter. Broad use label. Labeled for: substitution of cold to force flowering azaleas; to inhibit flower buds on vegetative azaleas; peduncle elongation of pompom mums; earlier flowering and increased yield of statice; induction of flowering of spathiphyllum. ProGibb T&O and GA 3 4% are labeled for growth promotion to overcome growth retardant effects on containerized and field grown ornamentals. Concerns The ph of spray solution should be below 5.0. Active as a drench; Collate label amendment pending. Use within 4 hours of mixing; do not save diluted solution. Results less predictable under high temperature conditions. Do not treat plants under environmental stress conditions. Not labeled for chemigation. Effective dose strongly affected by volume (soil active). Thorough coverage required. Avoid application to plants under conditions of environmental stress. Start with low rates (1-3 ppm) to overcome stunting, Repeat in 5 days if necessary. Fresco is labeled for chemigation. Over application or incorrect timing can cause weak stems and excessive stem elongation. Very potent growth promoter. Start with 1 ppm on most crops. Not labeled for chemigation. 323

333 Table 15.2 Other Plant Growth Regulators Used In The Production of Floricultural Crops (continued) Common Name/Trade Name(s) Dikegulac sodium Augeo (OHP, Inc.) Application Methods Foliar spray Comments Broad use label for non-food crops grown in greenhouse, lath or shadehouses, nursery and field sites. Inhibits terminal growth, thereby promoting lateral development. Apply to actively growing plants with at least two nodes to provide sufficient lateral development. Concerns May significantly delay plant development, especially at higher rates. Adjust water and fertilizer according to growth. Do not pinch or prune soon after treatment. Causes leaf chlorosis which may be persistent at high rates. Do not add wetting agents. Use the diluted solution the same day it is mixed. Methyl esters of fatty acids Off-Shoot-O (Cochran Corp.) Foliar spray Labeled for chemical pinching of actively growing azalea, cotoneaster, juniper, ligustrum, Rhamnus, and Taxus. Not labeled for chemigation. Ensure coverage of growing points. Do not spray more than once. 324

334 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses This table lists labeled rates of plant growth regulators (PGRs) for greenhouse crops, as well as recommendations based on research at North Carolina State University and recommendations by suppliers. Read the label for a complete listing of precautions. The degree of control can vary depending on a number of factors, including plant type, cultivar, stage of development, fertilization program, growing temperatures and crop spacing. When using a PGR for the first time, it is good to test the rate on a few plants prior to spraying the entire crop. Keep accurate records and adjust rates for your location. General recommendations: Plug culture and flat culture have different recommended rates. The rates in this table include recommendations for both plug (lower rates) and flat culture (higher rates). Apply ALL foliar sprays of plant growth regulators using 0.5 gallon per 100 square feet of bench area. See the dilution table (Table 15.4) for mixing instructions. Trade Name Rate BEDDING PLANTS To control plant height Abide / 6 to 66 ppm spray (2.9 to 32 A-Rest fl oz/gal) B-Nine/ Dazide + Cycocel / Citadel Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Bonzi/ Piccolo/ Piccolo 10XC/ Paczol/ Downsize Cycocel / Citadel Concise/ Sumagic to 0.12 mg a.i. drench for a 4-in. pot (apply 2 fl oz/4-in. pot) 800 to 5,000 ppm daminozide + 1,000 to 1,500 ppm chlormequat chloride applied as a tankmix spray 5 to 90 ppm spray. Use 30 ppm spray as a base rate and adjust as needed mg a.i. drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Precautions and Remarks Plug culture and flat culture differ in recommended rates. The rates shown in this table include both plug (lower rates) and flat culture (higher rates) recommendations. Apply ALL foliar sprays of plant growth regulators using 0.5 gal per 100 sq ft of bench area. Drench volumes and mg a.i. vary with pot size. Use the highest rate of Cycocel/ Citadel that doesn t cause excessive leaf yellowing, and then adjust the B-Nine/Dazide rate up and down within the labeled range to attain the desired level of height control. Conduct trials on a small number of plants, adjusting the rates as needed for desired final plant height and duration of height control. Not recommended for use on fibrous begonia or vinca. Drench applications are recommended only for bedding plants in 6-in. or larger containers. Not recommended for use on fibrous begonia or vinca. 800 to 1,500 ppm spray Conduct trials on a small number of plants, adjusting the rates as needed for desired final plant height and duration of height control. 1 to 50 ppm spray Conduct trials on a small number of plants, adjusting the rates 0.1 to 2 ppm drench as needed for desired final plant height and duration of height control. Apply spray as elongation begins (plant height about 2 to 4 in.). 325

335 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks BEDDING PLANTS To promote plant growth and overcome over- application of gibberellin- inhibiting PGRs ProGibb T&O 1 to 25 ppm spray Conduct trials on a small number of plants initially using 1 ppm unless previous experience warrants higher use rates. Following assessment of plant response, and if desired results were not evident, reapplication or an increase in rate may be warranted. Consult the label for additional precautions. Fascination 1 to 25 ppm spray Conduct trials on a small number of plants initially using 1 ppm unless previous experience warrants higher use rates. Following assessment of plant response, and if desired results were not evident, reapplication or an increase in rate may be warranted. The most common rates for use are 3 to 5 ppm. SEE LABEL FOR ADDITIONAL PRECAUTIONS BEFORE USE. To induce lateral or basal branching Configure 50 to 500 ppm spray The supplemental label allows legal use on greenhouse grown plants not specifically listed on the original label. See label for trialing suggestions and precautions. CHRYSANTHEMUM To control plant height Abide/ A-Rest B-Nine/ Dazide Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Bonzi/ Piccolo/ Piccolo 10XC/ Paczol / Downsize 25 to 50 ppm spray 0.25 to 0.5 mg a.i. drench for a 6-in. pot (apply 4 fl oz/6-in. pot) 1,000 ppm preplant foliar dip Apply when plants are 2 to 6 in. in height (about 2 weeks after pinch). Drench rates and application volumes vary with pot size. Rooted cuttings can be dipped in solution to thoroughly wet leaves and stems and then potted. Allow foliage to dry before watering in. For unrooted cuttings, dip stems in solution, remove to flat, cover to prevent dehydration and hold overnight under cool conditions. Stick the next day. 2,500 to 5,000 ppm spray Spray when new growth from pinch is 1 to 2 in. long. Some varieties may require another application 3 weeks later. 50 to 200 ppm spray Applications should begin when axillary shoots are 2 to 3 in. long. Sprays can be applied earlier to vigorous cultivars if additional control is desired. Sequential applications of lower rates generally provide more uniformly shaped plant than single-spray applications to mg a.i. Drench volumes and mg a.i. vary with pot size. Begin when (1 to 4 ppm) drench for a the axillary shoots are to 2 to 3 in. long. Uniform application 6-in. pot (apply 4 fl oz/6-in. is required. pot) 326

336 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks Concise 5 to 10 ppm dip treatment on cuttings Apply when the lateral shoots are 1.5 to 2.0 in. tall (about 7 to 14 days after pinching). Test for cultivar sensitivity. Multiple applications of the lower label rate may elicit a more satisfactory response and/or increasing the spray volume from 2 qts/100 sq. ft. to 3 qts/100 sq. ft. For Florida Only: use a foliar spray concentration between 5 to 10 ppm For medium to tall cultivars, increase the spray volume to 3 qts/100 sq. ft. 2.5 to 10 ppm spray Apply as a dip treatment on unrooted cuttings followed by a foliar spray in the low rate range. On rooted cuttings, use a solution of 2.5 ppm or less, followed by a foliar spray in the low rate range. Sumagic 2.5 to 10 ppm spray Topflor 7.5 to 25 ppm spray Based on NC State Univ. trials. Adjust rates for other locations. Use lower rates for less vigorous cultivars. COLEUS To control plant growth B-Nine/ Dazide + Cycocel / Citadel Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Piccolo/ Piccolo 10XC 2,500 to 4,000 ppm + 1,000 to 1,500 ppm chlormequat chloride applied as a tankmix spray 5 to 30 ppm spray See General Recommendations. Scheduling the crop to avoid excessive stretch is an effective means of controlling growth. 6 to 10 ppm liner root soak Irrigating liners within 24 hrs. prior to application results in a moderately dry substrate (the stage the plants would be watered, but not wilted). Soak for a minimum of 30 to 60 seconds. Transplant after 3 hours waiting period. Rate based on Michigan State University trials. 800 to 1,500 ppm spray Citadel / Cycocel Concise/ 10 to 20 ppm spray Sumagic GERANIUM To control plant height Abide/ 26 to 66 ppm spray A-Rest Bonzi/ Piccolo/ Paczol 5 to 30 ppm spray Apply to zonal geraniums when new growth is 1.5 to 2 in. long and to seed geraniums about 2 to 4 weeks after transplanting. Concise 3 to 8 ppm spray Use lower rates for less vigorous plants and higher rates for more vigorously growing plants. Flower delay on some cultivars can occur when using rates greater than 6 ppm. 327

337 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks Citadel/ Cycocel 800 to 1,500 ppm spray Make first application 2 to 4 weeks after planting plugs or rooted cuttings (after stems have started elongating). Multiple applications may be needed. Sumagic 3 to 6 ppm spray for cutting geraniums and 2 to 4 ppm spray for seed geraniums Topflor 15 to 25 ppm spray Apply to zonal geraniums when new growth is 1.5 to 2 in. long. To promote earlier flowering in seed geraniums Citadel/ Cycocel 1,500 ppm spray Make two applications at 35 and 42 days after seeding. Treated plants should flower earlier and be more compact and more branched than untreated plants. ProGibb T&O 5 to 15 ppm spray Make a single foliar application when first flower bud set is noted. Spray the entire plant until runoff. See label for precautions. To increase flower number and size in cutting geraniums ProGibb T&O 1 to 5 ppm spray Make a single foliar application when first flower bud set is noted. Spray the entire plant until runoff. See label for precautions. To increase lateral branching Augeo 1,562 ppm spray Labeled for ivy geraniums only. Collate/ Florel Trade Name Rate LILY, EASTER To control plant height Abide/ A-Rest 300 to 500 ppm spray Labeled for zonal and ivy geraniums. Use the lower concentration for ivy geraniums. It will also provide some growth retardant effect and delay flowering. Read the label for restrictions on timing of applications. Precautions and Remarks 30 to 132 ppm spray. Use 50 ppm spray as a base rate and adjust as needed to 0.5 mg a.i. (2 to 4 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Apply when newly developing shoots are 2 to 3 in. long; a second application when shoots average 6 in. long may be needed. Single drench should be applied when shoots average 3 to 5 in. long. Drench volumes and mg a.i. vary with pot size. Concise 3 to 15 ppm spray Apply when shoots average 3 in. tall. It s best to make only one foliar application per crop to 0.06 mg a.i. (0.23 to 0.5 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Apply when shoots average 3 in. tall. Use lower rates on cultivars such as Nellie White and higher rates for Ace. For Florida Only: use a solution concentration of between 0.05 to 0.12 mg a.i. (0.4 to 1.0 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot). 328

338 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks Sumagic 3 to 15 ppm spray Apply when shoots average 3 in. tall to 0.06 mg a.i. (0.25 to 0.5 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Drench volumes and mg a.i. vary with pot size. To prevent leaf yellowing Fascination/ Fresco 5 to 10 ppm spray Apply early season (7 to 10 days PRIOR to visible bud stage) and mid-season (7 to 10 days AFTER visible bud stage). Apply spray only to lower leaves to minimize stem elongation. See label. To prevent leaf yellowing and prolong flowering Fascination/ Fresco 100 ppm spray Apply late season (when first bud reaches at least 3 in. in length) and no more than 14 days prior to placement in a cooler or shipping. Apply to foliar and flower buds. See label. LILY, HYBRID To control plant height Bonzi/ 200 to 500 ppm spray Make first spray application when plants are 2 to 4 in. tall. Piccolo/ Piccolo 10XC/ Paczol 5 to 30 ppm bulb soak Soak bulbs in the solution for 15 min. prior to planting. Bonzi/ Piccolo/ Piccolo 10XC/ Paczol/ Downsize 0.25 to 0.5 mg a.i. (4 to 30 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Single drench should be applied when shoots average 3 to 5 in. long. Drench volumes and mg a.i. vary with pot size and cultivar. Concise 2.5 to 20 ppm spray Conduct a trial to determine optimal rates for each cultivar and adjust the rate as needed. Spray when shoots average 3 in. tall. If a second application is needed or a split application is made, apply when shoots average 6 in. tall. Usually 2 foliar spray applications at lower rate are more effective than 1 application at higher rate. Don t apply after visible bud stage. 1 to 3 ppm drench Drench volume varies with pot size. Apply newly emerged shoots when 1 to 2 in. tall. 1 to 10 ppm bulb soak Treatment soak time should range from 1 to 5 minutes and will vary depending on bulb size, cultivar, and final desired height. Lower rates may require longer soak times (5 to 10 minutes) than higher rates (1 minute). Sumagic 3 to 15 ppm spray Apply when shoots average 3 in. tall. Topflor 0.03 to 0.06 mg a.i. (0.25 to 0.5 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Drench volumes and mg a.i. vary with pot size to 0.5 mg a.i. (2.1 to 4.2 ppm) drench for a 6-in. pot Based on NC State University trials. Adjust rates for other locations. 329

339 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks To prevent leaf yellowing Fascination/ Fresco 5 to 10 ppm spray Apply early season (7 to 10 days PRIOR to visible bud stage) and mid-season (7 to 10 days AFTER visible bud stage). Apply spray only to lower leaves to minimize stem elongation. See label. To prevent leaf yellowing and prolong flowering Fascination/ Fresco 100 ppm spray Apply late season (when first bud reaches at least 3 in. in length) and no more than 14 days prior to placement in a cooler or shipping. Apply to foliar and flower buds. See label. LILY, ORIENTAL To control plant height Bonzi/ Piccolo/ 100 to 200 ppm bulb soak Ten minute soaks provided excellent results in NC State University trials. Cultivar response varied. Piccolo 10XC/ Paczol Concise 2.5 to 10 ppm spray See Concise label comments for hybrid lilies. 1 to 10 ppm bulb soak See Concise label comments for hybrid lilies. Concise/ Sumagic 1 to 10 ppm bulb soak See Concise label comments for hybrid lilies. Ten minute preplant soaks of 5 ppm provided excellent results in NC State University trials. Cultivar response varied. Topflor 0.5 mg a.i. drench (4.2 ppm); (apply 4 fl oz/6-in. pot) Optimal rate base on NC State University trials. Adjust rate for plant vigor. Drench volumes and mg a.i. vary with pot size. 25 ppm bulb soak Ten minute preplant soaks provided excellent results in NC State University trials. Cultivar response varied. To prevent leaf yellowing Fascination/ Fresco 100 ppm spray Apply early season (7 to 10 days PRIOR or AFTER visible bud stage). Apply spray only to lower leaves to minimize stem elongation. See label. To prevent leaf yellowing and prolong flowering Fascination/ Fresco 100 ppm spray Apply late season (no more than 14 days prior to placement in a cooler or shipping). Apply to foliar and flower buds. See label. LINER SOAKS To control plant height Piccolo/ Paczol 0.5 to 8 ppm preplant liner soak See label for detailed recommendations for chemical application techniques, adjusting rates for northern or southern locations, and the specific rates for achieving the desired level of activity. 330

340 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate NEW GUINEA IMPATIENS To control plant growth Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Precautions and Remarks 0.25 to 15 ppm spray Apply 2 to 4 weeks after transplanting. Cultivars responses to PGRs varies greatly. Test a few plants to determine rate for optimal control to 2 ppm drench (0.03 to mg a.i.) Drench volumes vary with pot size. See label for recommendations. Cultivars response to PGRs varies greatly. Test a few plants to determine rate for optimal control. Collate/ Florel 100 to 300 ppm spray To increase lateral branching and reduce premature flowering. Do not apply within 8 weeks of desired flower date. Topflor 5 to 15 ppm spray Apply 2 to 4 weeks after transplanting. Cultivars responses to PGRs varies greatly. Test a few plants to determine rate for optimal control. OSTEOSPERMUM To control plant growth B-Nine/ Dazide + Citadel / Cycocel Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Citadel/ Cycocel Concise/ Sumagic Piccolo / Piccolo 10XC 1,500 to 3,000 ppm + 1,000 to 1,500 ppm applied as a tank-mix spray 27 to 54 ppm drench (8 to 16 mg a.i.) during production 2 to 3 ppm drench (0.236 to 0.35 mg a.i.) Multiple sprays required. Stop applications after visible bud to avoid flower delay and smaller flowers. Not effective in NC State University trials. Drench volumes vary with pot size. See label for recommended volumes. Rates based on NC State Univ. trials. For holding plants. 750 to 1,500 ppm spray Two applications may be required. Two applications of 1,500 ppm (with the first applied at the start and the second at the end of the vernalization period) provided excellent results in NC State University trials. 1,500 to 3,000 ppm drench Drench volumes vary with pot size. See label for recommended volumes. 1,500 ppm worked well in NC State University trials. 3 ppm spray Recommendation based on European trials on a cultivar with prostrate growth. Rates less than 24 ppm were not effective in NC State University trials to 2 ppm drench (apply 3 fl oz/5-in pot) One application of 1 to 2 ppm (at start of vernalization) or two applications of 1 ppm (at start of vernalization) and 0.5 ppm (at end of the vernalizatioin period) provided excellent results in NC State University trials for 5-inch production. 4 to 8 ppm liner root soak Irrigation of liners that was done within 24 hours before application resulted in moderately dry substrate (stage plants are watered but not wilted). Soak for minimum of 30 to 60 seconds. Transplant after 3-hr waiting period. Based on Michigan State University trials. 331

341 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Topflor 20 to 60 ppm spray 1 to 2 ppm drench (apply 3 fl oz/5-in pot) Precautions and Remarks One application of 1 to 2 ppm (at the start of vernalization) or two applications of 1 ppm (at the start of vernalization) and 0.5 ppm (at the end of the vernalizatioin period) to 5-inch pots provided excellent results in NC State University trials. PANSY To control plant height Abide/ 3 to 15 ppm spray A-Rest Bonzi/ Piccolo/ Piccolo 10XC/ Paczol 5 to 15 ppm spray Apply when plants are 2 in. in diameter. Use higher rates for higher temperatures and more vigorous cultivars. Late applications may delay flowering. Concise/ Sumagic 1 to 6 ppm spray Apply when plants are 3 to 4 in. tall. Use higher rates for higher temperatures and more vigorous cultivars. Late applications may delay flowering. Topflor 2.5 to 7.5 ppm spray Based on NC State University trials. Adjust rates for other locations. Pansies are very responsive to Topflor, so start trials with lower rates. POINSETTIA To control plant height Abide/ A-Rest B-Nine/ Dazide B-Nine/ Dazide + Citadel / Cycocel Bonzi/ Piccolo/ Piccolo 10XC/ Paczol Bonzi/ Piccolo/ Piccolo 10XC/ Paczol/ Downsize 0.06 to 0.25 mg a.i. (0.5 to 2 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Drench volume and mg a.i. vary with pot size. Start with lower rates. 2,000 to 3,000 ppm spray Not effective in NC State University studies. 800 to 2,500 ppm + 1,000 to 1,500 ppm applied as a tank-mix spray Use the higher rates of this tank-mix spray on stock plants and for finishing crops in very warm regions. Outside of very warm areas, use the lower rates. Late applications can delay flowering and reduce bract size. 10 to 30 ppm spray Use higher rates of 15 to 45 ppm in southern Florida. Applications to slower-growing cultivars in cool climates should begin when axillary shoots are 2 to 3 in. long. For vigorous growing cultivars in warm climates, applications should begin when axillary shoots are 1.5 to 3 in. long. See label for other precautions to mg a.i. (0.25 to 3 ppm) drench for a 6-in. pot (apply 4 fl oz/6-in. pot) Drenches generally have less of an effect on bract size than sprays. Drench volume and mg a.i. vary with pot size. Start with lower rates. 332

342 Table 15.3 Growth Regulators for Floricultural Crops in Greenhouses (continued) Trade Name Rate Precautions and Remarks Concise 2.5 to 10 ppm spray Apply when the lateral shoots are 1.5 to 2.5 in. tall (about 10 to 14 days after pinching). Test for cultivar sensitivity. Multiple applications of the lower label rate may elicit a more satisfactory response. Do not apply after the initiation of short days. For Florida Only: use a foliar spray concentration between 10 to 15 ppm and do not apply after October 25. Citadel/ Cycocel 800 to 1,500 ppm spray For natural season crops in N.C., do not apply after mid- October to November 1. Late applications can reduce bract size and delay flowering. 3,000 to 4,000 ppm drench Drench volume varies with pot size. Consult the label for recommended volumes. Sumagic 2.5 to 10 ppm spray Topflor 2.5 to 80 ppm spray Use lower rates for less vigorous cultivars. See label for additional rate recommendations to 0.5 mg a.i. (0.25 to 4.2 ppm) drench for a 6-in. pot To promote plant growth Fascination 3 ppm spray (0.02 fl oz/gal) Use an early-season application during vegetative growth prior to the start of short days and flower initiation if promoting vegetative growth. See label for additional precautions before use. Fascination/ Fresco 3 to 10 ppm spray Use a late-season application to promote bract expansion. See label for additional precautions before use. 333

343 Table 15.4 Dilution Table for the Amount of Formulated Product per Gallon of Solution PPM AI Abide/A-Rest (0.0264%) (mm) Dazide/B-Nine (85%) (g) Citadel/ Cycocel (1.8%) (mm) Concise/ Sumagic (0.055%) (mm) Piccolo/Bonzi/ Paczol (0.4%) (mm) Piccolo 10XC (4%) (mm) Topflor (0.38%) (mm) Configure (2.0%) (mm) (milliliters) Augeo (18.5%) (mm) Collate (21.7%) (mm) Florel (3.9%) (mm) When mixing PGRs, great care needs to be given to accurately measure and apply the chemical. Drench applications vary by pot size and desired dose, so refer to the product label for exact mixing instructions. As always the label contains the legal mixing information. For a ready resource on preparing PGR solutions, download the PGR MixMaster app for your mobile device: This calculator was developed by floriculture specialists from North Carolina State University and the University of New Hampshire. It allows you to enter your own PGR costs and calculate solutions based on the rate desired and the amount of area to be treated. The calculator includes information on both spray and drench applications. It not only gives you the amount of PGR to mix per gallon or liter of water, but also provides the cost of the application based on the area or number of containers treated. Foliar sprays require an even application to obtain consistent results. For foliar sprays, measure out a known amount of chemical, add it to a known volume of water and apply the spray to a known bench area. Most sprays are applied at 1 gal. per 200 sq. ft. of bench area. For drench applications, measure out a known amount of chemical, add it to a known volume of water, and apply a known volume of the drench to each pot. The volume of drench applied increases with the pot size (specifics are listed on each product label). 334

344 Chapter 16 Water Supply, Irrigation, and Management David S. Ross, Professor and Extension Agricultural Engineer Introduction Producing plants in a greenhouse requires an ample supply of good quality water. A well-designed and maintained water delivery system makes the irrigation process very efficient. In the past, only individuals skilled in watering greenhouse plants could be trusted to do the job properly, and today these employees are hard to find. Automatic watering offers many advantages, including saving growers time that they can then spend on managing the water control system rather than performing the actual application. New sensor technology, wireless data transmission and real-time graphical display of data is going to improve water management in coming years. The emphasis has shifted today to both controlling the application and to catching and recycling the excess. Concerns now extend beyond the crop to the environment. Water Supply: Quantity and Quality A good well or municipal water supply is the first choice for a greenhouse water source. Clean water is essential for the small mist units or trickle emitters now frequently used. Screen or disk filters of 100 to 150 mesh or smaller are used to remove any sand particles that are pumped with the water. If surface water from a stream, creek, or pond is used, then a self-cleaning disk or screen filter is a good choice. However, if the water contains a lot of fine material, organic matter, or slime bacteria, a self-cleaning sand filter is recommended for removing the load of silt, algae, or other debris. At minimum, a flow rate of 5 gallons per minute (gpm) is needed to use a hose for hand watering. The actual water requirement depends on the size of the greenhouse operation and the type of irrigation system used. It is important to know the amount of water available before planning the irrigation system. Then, a system can be designed and divided into zones that match water demand to the available water supply. The system must have the capacity to water the mature crop in the number of hours allowed for watering each day. Water quality is very important for containerized plants that live in a small quantity of substrate. The plant may be sensitive to certain elements, and the substrate offers little buffering capacity. Have the water tested by a good irrigation water testing laboratory once or twice a year to ensure that good, quality water is available. Chemical treatment may be required when chemical pollutants, such as iron, sodium, hard water (dissolved calcium and magnesium), or bicarbonates, are present. Chlorine or an acid may need to be injected to correct a problem that otherwise might result in a clogged emitter or nozzle. A water softener may add harmful sodium while correcting another problem. Iron or bicarbonates may react with other elements during the watering process, creating precipitants that cause discoloration and hinder the sale of the crop. Water test results will enable a person to identify potential problems and recommend solutions during the design of the system. Water quality problems may affect long-term crops more than short-term crops because the exposure is longer. Water applied overhead onto the foliage may be more of a problem than water applied to the substrate. Water and Nutrient Management Water management is the key to nutrient management! Because nutrients travel in water, nutrient management is largely a matter of controlling the water applied to avoid leaching and runoff. Strategies for applying water more frequently in small amounts or applying water at a slower application rate tend to allow 335

345 the substrate to be wetted without excess leaching occurring. The goal is to reduce the leaching fraction to 15 percent or less. Also important is applying the correct quantity of nutrients onto the crop to ensure that there are not excess nutrient salts to cause plant damage if leaching is reduced. A well-designed, efficient irrigation system is the basis of a good water management program. It is clear that the less runoff produced, the less of a problem runoff creates later. Trickle and subirrigation do an excellent job of delivering water efficiently; overhead systems create large volumes of runoff and wet foliage increases the potential for pest problems. However, trickle systems are more expensive and labor intensive for many greenhouse crops. Water recovery and reuse (recycling) practices reduce the risk of losing nutrients. Applying liquid fertilizers by overhead irrigation creates the opportunity for nutrient loss. As little as 20 to 30 percent of the overhead-applied water falls into containers, depending on the spacing of the containers. The rest of the water (as much as 70 to 80 percent) falls onto the floor and may contribute to runoff. Hand watering or overhead sprinklers may result in a greater loss of water than application by microirrigation (trickle or drip emitters and small spray devices), but both can have the same leaching result. Reducing fertilizer and other chemical waste can save expenses both today and potentially in the future when environmental clean-up regulations are bound to be stricter. When you are setting up an irrigation schedule, use moisture sensors to monitor substrate moisture. Your goal should be to maintain a container s moisture level at close to capacity or between full and half capacity. This level reduces the chances of the plant becoming water stressed and growth being slowed. Applying the water at a low application rate, either by overhead sprinkler or by trickle irrigation, allows the substrate to be wetted with less chance of leaching. Even some trickle emitters apply water too fast for the coarse substrates that some mixes produce. Watering the substrate in a cyclic manner small doses several times a day will enable you to maintain an even moisture level over the entire day. Use a low-tension tensiometer, measuring moisture in the range of 0 to 40 centibars (0.4 bar or 40 percent of one atmosphere pressure), for greenhouse substrates. A moisture tension of 5 to 10 centibars indicates a dry substrate for many pine bark substrates. In a peat substrate, which holds more water than a substrate of pine bark, a reading higher than 10 centibars indicates a dry condition. A zero reading is wet and a dry reading depends on the water-holding capacity of the substrate. Most substrates hold very little water. A tensiometer may be less than satisfactory in substrates that contain large chunks of pine bark or other coarse material. The substrate must make good tight contact with the tensiometer and coarse materials do not. Capacitance sensors will provide much better moisture data. The new technology (2009) will provide real time display of moisture and other environmental data to the grower through capacitance sensors connected to radio nodes that will send the data wirelessly to the grower s office for graphical display on his/her computer. The grower will be able to observe the data and make irrigation control decisions. Also, for local control the radio node will be able to collect local sensor data, average it and send signals to solenoid valves to open and close at defined moisture setpoints. Plant models will eventually allow the grower to plan ahead to meet plant needs. A Good Working System Flow and Pressure A good working irrigation system can make a great difference in the management of a growing crop. If water application is nonuniform, part of the crop is receiving too much water in order that another part of the crop receives an adequate amount of water. No matter how growers adjust a watering schedule, this is a situation that hinders production of a good crop. Hand watering to make up the difference adds costs and takes growers away from the jobs they should be doing. 336

346 Pressure and pipe water velocity (flow rate) are two factors that can have a critical effect on the operation of an irrigation system. If you are planning a new water distribution system or have one that has been modified, either to a new system or an expansion of your system, note the following: A pipeline is sized for the water flow rate and for the distance the pipe must carry the water. The reason is that energy is lost in the form of pressure loss when water flows through a pipe. As water moves through the pipe it rubs or drags against the walls of the pipe and loses some of the pressure energy that is moving it along the pipe. The faster the water moves (higher velocity), the more friction is generated because turbulent flow develops, which disturbs the flow even more. This loss is called friction loss. Because of friction and other harmful effects of fast-moving water, engineers limit water velocity in pipes to 5 or 6 feet per second. The flow of water in a pipe (gallons per minute) is the product of the cross-sectional area of the pipe times the water velocity times 7.48 gallons per cubic foot. Area is in square feet. Velocity is in feet per minute or per second. Typically, a mainline pipe is designed to have less than 1 foot of head (0.43 pounds per square inch [psi]) loss per 100 feet of length. A friction loss chart is available for each type of pipe to aid in pipe selection. A pipe with low friction loss will have a more uniform pressure along its entire length. Laterals fed by this pipe will each have about the same pressure. Each nozzle or emitter along each lateral will discharge about the same amount of water if the pressure loss is low down the length of the pipe. The water applied will be more uniform over the whole irrigation zone. Although pipelines with low friction loss may cost a little more than the minimum-size pipe required, the result will be a better-watered crop; the overall quality of the crop may generate enough of an increase in profit to pay for the increased cost of the piping. Pipe flow capacities can be compared. The diameter squared can be used to estimate the ratio of water carried by one pipe size versus another. Of course, nominal sizes (store labeled sizes) are easier to use than actual inside diameters, so there will be errors. A 2-inch pipe will carry how much more water than a 1.5- inch pipe? The diameters are 2 inches and 1.5 inches, respectively. Compare 2 x 2 to 3/2 x 3/2 or 4 to 9/4. The ratio is 16/4:9/4 or 16:9, which says the 2-inch pipe carries 16/9:1 times more or about 1.8 times more water. Comparing flows with the same friction loss for Class 160 PVC (polyvinyl chloride) pipe, the real ratio is about 14:9 or 1.6 times as much, using the actual chart information. A pressure gauge is a very important tool that will tell a grower if the irrigation system is working properly. If the water pressure stays at the initial design pressure, then water application should stay the same. If the water pressure is low, there may be a break in the line or a nozzle missing. If the water pressure is too high, a line or several nozzles are clogged or a valve is closed. A pressure gauge is more frequently placed at the pump, but gauges on either side of a filter or on a mainline in the field is convenient for routine inspection. Changes in pressure are signals that something is wrong or that a filter requires cleaning. A water flow meter is another tool for monitoring the water flow. A continuous flow indicator shows the actual flow rate of the water, either on a meter or by a weighted object that is moved up a clear tube by the flowing water. An accumulating meter records the flow on a meter that shows total flow over a period of time. Some meters will show both. A flow reading on the continuous indicator meter should be the same gallons per minute each time. A variation may mean a problem exists. Additional Important Components of an Irrigation System In addition to the pressure gauge and flow meter mentioned earlier, several other components are worthy of discussion. The types of valves used can have an impact on the system. Gate valves open fully to allow water to pass with very little pressure loss or restriction of the flow. Turning the valve stem moves a gate up and down through the flow path of the water. Gate valves are sometimes 337

347 used to regulate the flow of water when pressure must be reduced. By partially closing the valve the water must move through a smaller opening and energy (pressure) is dissipated by the restriction. Extra energy is consumed in pushing water through the restriction. Ball valves open fully if you rotate an internal ball that has a hole through the center. When the hole is aligned with the pipe, water flows through; when the hole in the ball is rotated one quarter turn, the solid side of the ball blocks the flow. Both gate valves and ball valves work well; the gate valve opens more slowly and may reduce the problem of someone turning a valve open too quickly. Avoid the use of globe (common faucet) valves because the water must pass through a small opening in the valve that is restrictive and much pressure is lost. All valves are subject to damage if water freezes in them. Electric solenoid valves help to automate an irrigation system. The valves receive an electrical signal to activate an electromagnet, which causes the valve to open or close. By attaching the solenoid valve to a time clock or controller, you can set your irrigation system to function automatically at specific times and for specific periods of time. A solenoid valve connected to a time clock or moisture setpoint controller is a good management tool for freeing an operator s time. Air vents (vacuum breakers) are important at elevated points in irrigation systems; the vents allow air to escape as the pipe is filling with water. The vent prevents the air from blocking the water passage through the system at elevated points. Also, the air vent allows air to enter as the system drains so a vacuum does not develop to pull dirty water in through emitters or other openings in contact with the substrate. The vent closes as the water rises into the vent. A ball is used to seal the vent. Backflow preventers prevent the contamination of the water supply. A hose bibb vacuum breaker or a check valve prevents dirty or chemical-laden water from flowing back into the water supply. Backflow preventers are important for protecting the drinking water supply from contamination. Filters are a necessary component for drip and trickle irrigation systems. Screen filters are made with screen material; screens of 100 to 150 mesh meet the requirements for passing the relatively clean water needed by drip/trickle systems. Disc filters, which have grooved flat discs that stack together, have a larger capacity for catching particles and are stronger against high water pressure than screen filters. Both of these filters are improved by the addition of self-cleaning (backflush) capabilities. For heavy loads of fine or organic materials, the sand or media filter has more capacity for trapping and holding debris in its bed of sand. The sand or media filter is also available as a self-cleaning unit. Mesh numbers, which indicate number of threads per inch, correspond to the size of openings. The higher the mesh (number), the greater the number of threads and the smaller the openings (Fig. 19.1). Polyvinyl chloride (PVC) pipes are lightweight, low-friction pipes that feature a low initial cost, ease of installation, and resistance to corrosion. Main distribution lines can be buried or placed overhead. Schedule 80 PVC is a heavy-walled gray pipe that is stiff for unsupported overhead uses. Schedule 40 is heavier than the Class 160 or Class 200 white PVC pipe. Light may penetrate the pipe particularly the thinner-walled pipe to support algae growth. Over a long time, sunlight deteriorates unprotected PVC pipe; use paint or opaque wrap to block the light and to protect the pipe. Polyethylene (PE) pipe is the flexible, black pipe commonly used for underground supply lines and bench systems. It features a low initial cost and is easy to install using insert (barbed) fittings; it is also lightweight and resistant to inside corrosion. Its disadvantages are that it can be damaged by sharp objects, it cannot be used for hot water, and it must be supported in overhead applications. Use nylon or brass fittings and stainless steel clamps with it. The suggested pressure rating is 100 psi or greater. 338

348 Figure 16.1 Irrigation Filters Filters are necessary componenents for drip and trickle irrigation systems. Types of Watering Systems Greenhouses have a range of irrigation systems from simple hand watering by hose to complex computeroperated systems, such as hydroponic or ebb and flood systems. The choice of a system may be based on the crop, the container used, the type of house, economics, or other factors. Although complex systems are costly and require lengthy set-up and management inputs, they will save on labor and can water large areas. Plant production will likely be of better quality in a greenhouse using a computer-operated system; these systems enable the grower to maintain good control. Simple systems are low in initial cost; however, they can be expensive in terms of labor costs because hand watering requires an employee. Water quality must be good for all systems that use small emitters or nozzles. Filtration is usually a must to avoid clogging of small orifices. Hand watering is both the least expensive initially and the most versatile of watering systems. It is a popular system, particularly with vegetable and bedding-plant growers who keep many different crops in one house. The operator has total control over the watering and uses his or her knowledge of the crop and substrate to apply different amounts of water as needed. The quality of watering by hand may vary more than the quality of watering by machine. With hand watering a great deal of water is wasted and all plants in a given flat are not likely to be watered uniformly. Hand watering is accomplished with hoses that are dragged along the floor. Different sizes of water breakers (sprinklers) are used on the hose ends to distribute the water. Hang hoses from the ceiling on pulleys running on a cable. This keeps the hose from dragging on the floor and carrying disease organisms from one end of a house to the other. Stationary sprinklers usually provide more uniformity than hand watering if the system is properly designed water coverage needs to overlap and is properly maintained. These systems can be automated 339

349 and can irrigate an area much faster than hand watering systems, significantly reducing labor costs. Careful design is essential for achieving even water pressures, high uniformity, and water-use efficiency, while at the same time reducing system costs. Maintaining good water quality helps keep nozzles from wearing out. A wide range of sprinklers are available, from spray stakes to impact/gear-driven sprinklers. In designing a system, your goal must be maintaining uniform coverage over the width of the benches or beds, without excessive waste. Uniform coverage requires overlapping of the sprinklers. It is difficult to work out sprinkler placement for achieving uniform coverage. Trickle emitters in individual containers offer both uniform coverage and highly efficient water usage. Careful design and operation of a trickle system results in a system that can out-perform others besides being very good for hanging baskets and widely spaced large containers. Less water is wasted and nutrients can be delivered directly to the plant root zones. These systems are expensive and require more in management skills and labor for installation and maintenance than overhead sprinklers do. Misting or fog systems are used to maintain substrate moisture levels as well as the humidity around germinating plants, young seedlings, and rooted cuttings in closed areas of a greenhouse. High-pressure fog works well for humidity because the small droplets stay in the air longer and do not overwet the substrate. A fog is used for evaporative cooling during ventilation in greenhouses. For propagation, use two time clocks: one is a 24-hour clock that allows the mist system to function at certain time intervals during a 24-hour day; the second is an interval timer that allows the mist or fog system to operate for a few seconds every few minutes. The interval between mistings is adjusted according to weather conditions. Time controllers are available to replace the individual timers. Watering booms or carts are another alternative system that works well for single crops in a house. The carts run on the floor or a guide rail and the booms usually hang from a ceiling-mounted track. Inverted nozzles hang from an overhead boom or mobile apparatus. The movement is uniform over the top of the plants and the boom or carts can be automated with timers. Nozzle height and spacing are critical to assuring uniformity. These systems, which can be expensive and complex, require periodic maintenance. Booms and carts can be further automated with solenoids and environmental sensors. A computer can move the booms or carts to specific locations for watering select areas. If you vary the speed, the system can apply varying amounts of water to different parts of the greenhouse to meet crop requirements. Ebb and flood and hydroponic systems deliver water and nutrients to the roots of plants. Ebb and flood systems require level floors or benches. Water is pumped onto the floor or bench to a depth that allows the substrate to be wetted; then the water is drained away. Drainage allows the roots to receive air necessary for healthy growth. The cyclic process is repeated as needed to maintain substrate moisture. Ebb and flood can be used for a variety of container sizes, which makes it a flexible system. Hydroponic systems can be of the ebb and flood design or other designs. Hydroponic systems may contain a substrate or consist of a closed trough in which the roots hang into the flowing water. The hydroponic solution contains all the nutrients that the plants receive. The nutrient solution is pumped over the roots at intervals timed for maintaining plant moisture. All these hydroponic systems are expensive and require a large initial investment and advanced management skills. They are closed systems that usually recycle the water they use, which results in water conservation. Complete automation is possible with these systems. The advantage of trickle and ebb and flood watering methods as well as hydroponic systems that are not ebb and flood is that the water is applied to the substrate and not to the foliage where disease organisms might be encouraged to develop. Water is conserved or can be recycled to reduce waste. Nutrients can be applied without polluting the ground. Recycled water may require treatment to avoid the spread of disease. 340

350 Water-Related Disease and Other Problems Irrigation waters carrying fertilizers or other chemicals that are lost from the plant container may enter the surface drainage or the groundwater and cause pollution. While pollution carries potential future costs, the loss of fertilizer is a present cost of production. Reducing these losses can save expenses both today and in the future. Recycling irrigation water is one solution; better management of irrigation application and scheduling is another. The development of closed systems with recycling is worthy of consideration. Disease transmission is a major concern associated with recycling. Many operations have little or no trouble with disease transmission, which indicates that some irrigation system designs may be better than others; outdoor retention facilities, for instance, may be hostile environments for disease organisms. Pathogens, mostly water molds such as Phytopthora and Pythium, may be present. Treatment with chlorine, bromine, or another disinfectant may be essential to controlling the spread of disease. If an active residual of 1 or 2 ppm of chlorine remains after watering takes place, treatment should be complete, unless large particles are present in which disease organisms can hide. Filtration is a part of successful treatment. Keep plant foliage dry and avoid splashing water from the container onto the foliage. Cleaning the greenhouse and internal water retention facilities between crops or at least annually is a good maintenance practice to avoid the carry-over of any disease organisms. Algae are single-celled microscopic plants that multiply quickly to form a slime layer that can dry as a crust. Algae, which are not parasites as diseases are, do not attack plants. Like all plants, algae contain chlorophyll and produce their own food when conditions are right. Blue-green varieties are common in greenhouses. Algae cause many problems in the greenhouse environment, including: Clogging irrigation lines, misting systems, irrigation mats, and emitters Impairing the functioning of cooling pads Producing an impermeable layer on media surfaces that interferes with water penetration Harboring shore fly populations Making potted plants less desirable for customers Reducing levels of reflected or incoming light Causing slimy surfaces on walkways, which creates a safety hazard Creating a mess Competing with plants for nutrients Like all plants, algae need light, water, nutrients, oxygen, carbon dioxide, and heat, all of which are abundant in the greenhouse. Algae may be present in all waters, with the possible exception of deep well water. Algae are present in the air as dust, sometimes at very high levels. For these reasons they are able to appear quickly whenever conditions are right. Culturally, manipulating the conditions that encourage the growth of algae can reduce their presence. Painting translucent water pipes and fertilizer stock tanks black helps to keep light out. Cleaning the fertilizer tank between irrigations and using controlled-release fertilizers help to slow the flow of nutrients. Allowing surfaces to dry out between irrigations and sterilizing soils also help to reduce the number of organisms present. Chemical treatment with chlorine and other commercial products reduces the algae population. Sanitation is important for gaining and maintaining control of algae or disease. Cleaning the greenhouse and any water retention basins between crops or on an annual basis will help to control algae and diseases. Clean any reused containers. Regular sanitation is a good management practice. 341

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352 Chapter 17 Irrigation: Too Wet or Too Dry? Will Healy, Technical Services, Ball Horticultural Company Introduction Improper watering is the major cause of diseases and cultural problems that plague growers. Experts in the field often notice that growers are keeping their crop too wet. Growers seldom allow the soil to dry sufficiently after watering, which promotes good root development. At other times, however, growers let the soil dry too much, which causes stunting. Although it is easy for experts to say this crop is too wet or too dry, the question is, How to train growers to keep crops wetter or drier? The solution is to train the grower to learn how to allow the soil to dry to a specific soil moisture level before irrigating (Table 17.1). Instead of saying drier today, for instance, say, keep at a level 3 today. Table 17.1 Five Soil Moisture Levels Moisture Level State of Soil Soil Appearance 5 Wet. The soil is saturated. Water flows freely out of the soil. When soil is placed in the palm of your hand and compressed slightly, water runs out. Dark, almost black. Glistens with free water. Sticks together and feels mushy, like you re squeezing a water balloon. 4 Medium Wet. When soil is placed in the palm of your hand and squeezed, water will readily drip out of your hand before your fingers touch your palm. 3 Medium. When soil is placed in the palm of your hand and squeezed till your fingers touch your palm, water will drip but not run out of your hand. 2 Medium Dry. When soil is placed in the palm of your hand and squeezed, no free water or drips are present. The soil is spongy and squeaky when compressed. 1 Dry. When soil is placed in the palm of your hand and squeezed, water cannot be squeezed out of the soil. The soil is not squeaky. Dark brown. Sticks together after squeezing. Brown with light brown pieces. Crumbles apart after squeezing. Light brown with tan pieces. Crumbles apart after squeezing but sticks together. Tan to white. Crumbles apart after squeezing and will blow away; doesn t stick together. 343

353 When growers irrigate crops, the recommended method is to water thoroughly by irrigating to a level 5. This answer, however, prompts the next set of questions: At what soil moisture level do growers irrigate again. When the soil is at level 5 or 3, for instance? And how much should growers irrigate? Until the soil reaches a level 4 or 5? Growers can get themselves into trouble if they maintain the same moisture level (e.g., level 4) throughout the entire production period. Be sure to determine the correct soil moisture levels to follow during various stages of plug production (Table 17.2). Table 17.2 Optimum Soil Moisture Levels During Plug Production (Dry soil = 1; Medium dry soil = 2; Medium soil = 3; Medium wet soil = 4; Wet soil = 5) Crop Stage A: Germination Stage B: Cotyledon unfolding Stage C: Root and Shoot Development Impatiens Pansy Petunia Verbena Vinca Stage D: Preparing for Transplant 344

354 Chapter 18 Precision Irrigation for Nursery and Greenhouse Crops Andrew Ristvey, Extension Specialist, Water and Nutrient Management, and John Lea-Cox, Extension Specialist, Nursery Research Introduction Water is arguably the most important variable that we can control in growing plants, especially in contained environments like a pot or a tray, where roots have minimal space to explore, and where volumes are limiting for water application and retention. If the plant shows water stress (i.e. wilting leaves), it is most likely too late. Growth has been greatly reduced and plant health probably compromised. Simply running irrigation at a set time of the day may not deliver water to the plant when it is actually needed, or most often it results in over-watering which leaches nutrients and can contribute to increased disease. To maintain good plant growth and optimize irrigation, so that water and nutrients are not wasted, irrigation managers need to integrate a variety of environmental cues to determine irrigation timing and duration. This chapter will focus on how you can improve your irrigation system efficiency firstly by using a simple audit technique, and then secondly by making better decisions by using advanced irrigation tools (wireless sensor networks, WSN). This chapter will summarize how WSN work, describe various sensors and their deployment, and illustrate how an irrigation manager can get the most from the data they provide. Irrigation scheduling is a challenge in intensive horticultural operations. For the most part, irrigation scheduling is managed through grower intuition or experience (Bacci et al., 2008; Jones, 2008; Lea-Cox et al., 2009, Lea-Cox, 2012). The large variety of plants, their specific needs and differences in container sizes, crop age along with seasonal changes in water needs and a host of other issues make these irrigation decisions more complicated than one may imagine (Lea-Cox, 2012). Timely water applications are important to maintain plant growth and root health. Over-application can lead to nutrient loss through leaching, root stress from saturated root zones with low oxygen, and water waste. Under-application results in reduced plant growth, root stress and sometimes root death which can contribute to pathogen infestation. Irrigation System Efficiency Regardless if a WSN is being considered, the first step for any operation is to conduct an irrigation audit on the current irrigation system to increase irrigation efficiency. Briefly, an efficient irrigation system is one that applies the lowest volume of water to evenly irrigate crops in a way that is both cost- and energy-efficient. Efficiency can be measured by how uniform the applied water is distributed across a growing bed or bench (Distribution Uniformity). Efficiency can also be measured by the amount of water applied (Application Efficiency). The two are not necessarily mutually exclusive; each has different implications. A detailed explanation of how to do an irrigation system audit quickly and easily can be found online in The Green Industry Knowledge Center for Water and Nutrient Management (Ross, 2008; see References for website). Irrigation efficiency is not only affected by the irrigation system itself (Distribution Uniformity), but also the decisions being made about irrigation timing, plant placement etc. A well-performing irrigation system can still be inefficient if the irrigation manager over irrigates and water passes through the root zone and leaches out the bottom of the pot or tray. For instance, a micro-irrigation system applies water directly to the plant pot via a drip stake or spray stake. If the emitters are delivering water equally to all plants, it would be considered to have a high distribution uniformity. However, if too much water is applied, it would lower 345

355 the application efficiency of this normally efficient system. Apart from testing the irrigation system itself, application efficiency can be simply verified by examining the Leaching Fraction (LF), or the fraction of applied water that comes out the bottom of the pot. Detailed procedures for assessing LF are given in Bilderback and Lorscheider (2007; see References for website). An irrigation system audit provides an accurate examination of the whole system itself. Considerations like appropriate line pressures throughout the system are important. Irrigation nozzles are designed for efficiency at specific water pressures. Nozzle or emitter age and wear, along with foreign material build-up both biological (algae) and chemical (calcium and iron) in the equipment will have a negative effect on overall efficiency. Additional factors include overlapping irrigation coverage, pipe size and ability to supply enough water while maintaining pressure all play a role in efficiency. A Lower Quarter Distribution Uniformity test (LQDU) in any growing bed or bench under investigation can quickly identify these problems. The LQDU test simply shows how much and where water is being applied within the area being tested. The LQDU identifies how well distributed the irrigation water is being applied by the system to the plants. Since irrigation timing is often adjusted to irrigate those areas of the production beds which receive the least amount of water, distribution uniformity is important so that all plants receive as equal amount of water as possible. In other words, good distribution uniformity means that plants are receiving relatively equal amounts of water. In this way, under or over-irrigating is minimized, which is important for several reasons. Over application leads to wasted water, nutrient leaching and over-saturated root zones. Under-application leads to loss of plant growth and root stress. These tests are Best Management Practices (BMPs) and alone, can be extremely beneficial, not only for environmental, but for economic reasons. The procedures for a LQDU test can be found in Ross (2008; See References for website) Even though an irrigation system is highly efficient, there can be a lot of guess work when deciding when and how long to irrigate. Many irrigation managers have good methods for determining irrigation needs of different species and container sizes throughout the day. However, in many cases, especially with large nursery and greenhouse systems, a large amount of time is spent checking pots and plant conditions to determine when irrigation is necessary. There are days when water is not needed or days where multiple irrigations should be applied to plants. Different plants require different amounts of water and at different times than others. Many decisions about how much water and where need to be made without enough information. Determining when the plant needs water is the first step to increase application efficiency. Irrigation Scheduling Many different ways of scheduling irrigation other than time-based systems have been used with success (Lea-Cox, 2012). These include load cells, which schedule irrigation based on water loss by weight (Raviv et al, 2000), calculating water balance using rainfall and estimates of evapotranspiration (Allen et al., 1998), plant physiological measurements including stomatal conductance and water status (Jones, 2004) and direct soil moisture measurements with sensors (Topp, 1985; Smith & Mullins, 2001; Smajstrla & Harrison, 1998), to name a few. This chapter focuses on the latter since these direct measurement tools have shown to be more reliable and cost-effective for practical purposes (Jones, 2008). Sensor Technologies Moisture sensors, such as tensiometers, neutron probes, or gypsum blocks, have been used for irrigation systems for decades. Most function well in certain growing systems, especially in-ground (soil) applications. However, these technologies are not necessarily suited for soilless substrates or highly porous, organic media. More recently, sensor technologies that automatically relay environmental and soil data to the grower in real-time have been developed. These tools allow growers to accurately monitor and automatically control irrigation events in soilless substrates and container production. The rest of this chapter will discuss WSN deployment and how to use their information to improve upon the efficiency of your irrigation system. 346

356 Figure 18.1 A schematic of a farm-scale WSN for precision irrigation scheduling Adapted from Balendock et al., 2009 to illustrate networks deployed by our group (Lea-Cox et al., 2012) Measuring Water in Soils or Substrates The water content of soil or a substrate can be measured either by matric potential (the amount of force or suction a needed to pull water from the soil or substrate particles) or by volumetric water content (VWC, the percentage of water in a certain volume of soil). The former takes into account that not all water in a soil or substrate is available to plants. In soils this is typically affected by particle size. Tensiometers have been utilized to measure soil matric potential measurement for decades. However, since soilless substrates are quite porous, tensiometers usually do not work well since they require good contact with water between substrate particles. Since soilless substrates dry out rapidly, contact with the water is often lost, and the tensiometer then needs to be reset. On the other hand, measuring volumetric water content by time domain reflectometry (TDR) or capacitance sensors (both using electromagnetism to determine soil water content) is very reliable. However, VWC does not take into account how much water is available to plants (matric potential). Both TDR and capacitance rely on sensors that measure a relatively small volume around them. Since both soils and soilless substrates can vary in porosity within a small spatial area, an accurate representation of moisture measurement is important. Strategies for sensor placement are therefore important, so more accurate estimations of water content can be achieved. Wireless Sensor Networks A WSN is system of radio transmitters/data loggers (called nodes), that are designed to collect and transmit data from various sensor inputs. Additionally, newly-developed nodes, using sensor data, have the potential 347

357 to independently control irrigation events by powering a solenoid/valve. Figure 18.1 graphically explains the WSN system that the University of Maryland and other partners have deployed in numerous commercial nurseries and greenhouses around the U.S. (Lea-Cox et al., 2013). The nodes can wirelessly transmit the sensor data to a base-station and computer with a software program that can integrate and graphically display the sensor data. If the computer is connected to the internet, this software program also is configured as a password-protected website for the farm, so the data is accessible from anywhere in the world. Cellular (3G) nodes are also available for locations unable to access internet directly from a computer/basestation. The 3G data is sent to a cloud server via cellular network (SIM card) in the node. The data is then downloaded from this remote server. A software program with a graphic user interface (GUI) makes setup and deployment relatively easy. Most importantly, data interpretation is user friendly, intuitive and allows for quick decisions. These WSN can be used for either monitoring (where the manager makes the decision to irrigate) or automated control using the sensor information (where the manager sets the threshold values for triggering that event). Crop models which use a multitude of sensor data can also be incorporated for more advanced decision-making, if required. A distinct advantage of these WSNs is that they are both scalable (i.e. nodes and sensors can easily be added to the network) and the nodes are also reconfigurable. This means that a nursery operation can start with a small WSN system and gradually work up to larger systems when needed. A small WSN (minimal two or three nodes with a base station) can be deployed and used for monitoring until a level of understanding and comfort is reached by the user. Sensor Placement Sensor networks deliver reliable information to the irrigation manager in real time, so decisions can be made quickly. However, choosing where to place sensors will depend upon the needs of the manager and the plant species being grown. Sensor placement should be considered on two levels: (1) placement in the production area (large scale) and (2) placement in the root zone (small scale). Both decisions are important to understand and measure variability in irrigation system delivery and the water use of different species. At the operational (large scale) level, the question to ask is where does the irrigation manager have the most trouble? Things to consider include which plants are more sensitive to water, either needing more or less than average plants or which locations within the nursery are most problematic for irrigating efficiently. Remember that low irrigation system efficiency (high variability) leads to dry spots in the production area, which then leads to over-watering of other areas to compensate. In container (small scale) systems, where roots are contained in limited volumes, timing of irrigation events is critical. Available water in the container can be used quickly (sometimes within hours) and must be replenished. Cyclic irrigation, where irrigation times (duration) are reduced but irrigation frequency is increased, is the best management technique to maintain adequate water in the container. However, daily weather conditions determine plant water use, and timed irrigation events can either over-irrigate or under-irrigate plants. Sensors provide water content information for those plants/production areas which are chosen by the grower. If irrigation scheduling is based on sensor data, avoiding highly variable environments will aid in more precise measurements. We have found if the sensor is placed in the middle of the container (or first 6 inches of the root profile, in soils), this set-up captures much of the variability associated with roots at the surface rapidly taking up water. We also see water running through the root profile to lower depths (e.g. leaching in porous substrates). By adding an extra sensor at a lower depth (say in soil or larger pots), a grower can quickly gauge how long to irrigate, which typically is the hardest decision to make. Most growers find that they can typically halve their irrigation events, saving considerable water, but also increasing the flexibility for repeated, cyclic irrigations for those crops which need it. In soils, depth is a key issue. Experience shows that knowledge as to where the majority of the root systems are located is key to placing sensors, similar to container systems. In many cases this placement is 348

358 approximately 8 to 12 inches below the soil. Knowing how water moves through the soil profile (which is dependent upon soil particle size and structures like plow pans or a shallow water table) should factor into sensor placement. While soil particles are typically small and make good contact with sensors, rocks near sensors can cause anomalous data. Poor insertion that results in air around the sensor can also cause low sensor readings. This problem is simply solved by careful installation and saturating the soil/substrate so that particles settle around the sensor, thus ensuring good contact. Understanding the technology is important, and asking for professional advice for sensor installations is wise. Understanding Variability When starting, taking an average of 3-4 sensors inserted in similar container sizes at similar depths is important to understand the variability of the information you are getting. It also indicates how accurate the information may be from the sensors. The next point to make is understanding the difference between precision and accuracy: Precise information implies that data has low variability, but it does not imply that the information is accurate. Figure 18.2 shows four scenarios of data collection and interpretation, illustrated through a set of targets. Each shows how data can be collected and interpreted as though the bulls-eye was the unknown true value. In the best of both worlds, both precise and accurate data is most desirable. But it is not acceptable to have imprecise data that averages to an inaccurate value. Also, precise data may be inaccurate, but one can correct this by adjusting a sensor position or by doing a soil-specific calibration (which is quite easy to do). However, one can see that it may be just as good to have imprecise data, so long as the average of that data equals the true value, and in this case, the water content in the pot or soil. The only way one can really find this information is by initially sensing at least four plants and observing how the data converge or diverge over time. Consulting a professional typically always pays off in terms of time and getting the best data in the shortest amount of time. Figure Different data collection scenarios Targets illustrate the different scenarios of data collection and making inferences from data, considering precision and accuracy. Interpreting and Decision Making Once data start coming in from a newly deployed network, an equally important part of the WSN is how the information is managed and quickly displayed in an easily understood format. The software is probably the most important part of the system. The graphic user interface (GUI) is jargon for how the data is incorporated into a database by a software program, which is then summarized and visually displayed on your computer. In other words, the GUI downloads all the sensor data from all the nodes and converts them into a graphical form, giving the user a visual way to see real-time data. In Figure 18.3, potting substrate moisture content is displayed in a typical GUI in the form of a line graph for Cornus florida trees in 15 gallon pots during 4 days between July 17 th and the end of July 20, Four lines go across the graph and show soil moisture as Volumetric Water Content (VWC). Each of the four lines represents data coming from one moisture sensor placed in an individual pot. Note the peaks in the lines 349

359 Figure Typical container moisture dynamics before and after irrigation events in four Cornus florida trees. Data is graphically displayed using the most recent version of DataTrac v. 3.2 (Lea-Cox, 2012). which show irrigation events and subsequent dry-downs (valleys). The irrigation manager typically applies water to the pots three times a day in short duration and the average VWC for the pots are kept around 50% by the irrgation manager. As the pot drains, the WVW decreases. Additional information about irrigation volume applied is also being recorded and are shown as vertical lines at the bottom fo the graph. These data come from flow meters attached to the WSN. Note that the sensors are not showing the same VWC for each pot. The VWC difference between plants is most likely due to some plants being larger, having more leaves, and using water faster than others. The sensor data from larger plants will be more dynamic (i.e. it will move down more rapidly). However, differences in VWC readings can also be due to differences in sensor placement, variability in the substrate including air pockets around the sensor, or lack of application uniformity in the irrigation system, as previously noted. Using sensor-based information to decide the timing (frequency) of irrigation events then becomes much easier, since one can determine a VWC setpoint, based on the average of the four plants. The rapid fall of the peaks in Figure 18.3 indicates that overwatering occurred along with some leaching. During subsequent studies with sensor-controlled irrigation (detailed in Belayneh et al., 2013), irrigation durations were reduced from 6 minutes to 3 minutes, greatly reducing the potential leaching from each irrigation event, especially in the smaller container volumes. Sensor-based irrigation resulted in water savings of between 40 and 70%, depending on season and species (see Belayneh et al., 2013). Note that these savings were achieved when compared to irrigation scheduled by very experienced irrigation managers. Benefits Sensor networks have been deployed and extensively tested in nursery and greenhouse operations for both monitoring and automated irrigation control. WSN systems can be attached directly to solenoids and can independently operate irrigation (Belayneh et al., 2013), saving both time and labor. Challenged with time- 350

360 based irrigation scheduling and the experience of the irrigation manager, these WSN systems are being utilized for irrigation control and have consistently shown increased efficiency in water application and a return on investment, sometimes in less than a growing season (Chappell et al., 2013; Belayneh et al., 2013). Both environmental and economic benefits have been demonstrated (Lichtenburg et al., 2013; Majsztrik et al., 2013), the scale of which may depend on your location. Challenges We have pointed out the major challenges that exist in deploying a WSN system. Variability in production areas, type of production system (containers vs. field), and the variety of plant species need to be considered. Most importantly, how these factors affect the information being gathered is vital to consider. For example, in an above-ground container nursery operation, seasonal plant-water needs are based on daily weather, irrigation uniformity, and container size. Correct sensor placement will integrate all the factors to give a reliable estimate of daily plant water use. However, if sensors are not placed correctly, and the information is highly variable, making decisions from that information is not going to be accurate. For instance, sensors placed in containers under a poorly maintained irrigation system with low distribution uniformity will give highly variable information; i.e. very wet and very dry readings together, making determinations for efficient irrigation cycles difficult. Sensor systems do not compensate for poor irrigation system design, nor for poor irrigation management. They only provide added valuable information when systems and management are already as good as possible. Having a sensor in every container is not practical, nor economically feasible. Smart implementation of WSN entails starting with a small network and sensing a couple of indicator species or problem areas and learning from the information provided. In time, a WSN can be expanded to additional areas, or exiting nodes and sensors can be moved to other species or areas where information is needed. Since many of these networks presently communicate through radio signals and line of sight is often necessary between nodes and base station receiving antennas, topography (hills) and long distances (>1 mile between base station and nodes) can attenuate signals. These systems are becoming more robust, and at the very least, additional nodes can be positioned as signal repeaters to overcome obstacles. Additionally, as previously mentioned, cellular (3G) nodes are available for these situations which transmit data directly to a remote server for downloading into the software. In these cases, added cost should be expected. Summary A number of distinct advantages can be realized through the use of WSN systems. Sensor networks can play an important role in providing real-time information to irrigation managers about the water status of their crops; information that most growers take an enormous amount of time to evaluate every day. With this information, irrigation managers can make much better and more timely decisions on when to irrigate, increasing the efficiency of how water is utilized in nursery and greenhouse operations. Efficient use of water can reduce economic costs in many ways. Plant water requirements can be satisfied without guesswork, potentially increasing plant quality by improving growth and better management of diseases caused by water stress (by both under and over application). Savings in time and labor may be reduced by having information at the fingertips of the managers. Additionally, the environmental benefits associated with reduced water use can be realized with reduced nutrient and agro-chemical use. 351

361 References Allen, R. G., Pereira, L. S., Raes, D. & Smith. M Crop Evapotranspiration: Guidelines for Computing Crop Water Requirements. FAO Irrigation and drainage paper no.56. FAO, Rome, Italy. Bacci, L., Battista, P. and Rapi, B An Integrated Method for Irrigation Scheduling of Potted Plants. Sci. Hortic. 116: Belayneh, B.E., J. D. Lea-Cox, and E. Lichtenberg Benefits and costs of implementing sensorcontrolled irrigation in a commercial pot-in-pot container nursery. HortTechnology 23: Balendonck, J., Stanghellini, C., Hemming, J., Kempkes F.L.K. & van Tuijl, B.A.J Farm Level Optimal Water Management: Assistant for Irrigation under Deficit (FLOWAID). Acta Hort 807: Bilderback,T.E. and M.R. Lorscheider, Best Management Practices: Overhead Irrigation. In: Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. J.D. Lea-Cox, D.S. Ross (eds.). College Park, Maryland. Chappell, M., S.K. Dove, M. W van Iersel, P.A Thomas and J. Ruter Implementation of Wireless Sensor Networks for Irrigation Control in Three Container Nurseries. HortTechnology 23: Jones, H.G Irrigation Scheduling: Advantages and Pitfalls of Plant-Based Methods. J. Exp. Bot. 55: Jones, H.G Irrigation Scheduling - Comparison of Soil, Plant and Atmosphere Monitoring Approaches. Acta Hort. 792: Lea-Cox, J.D., Ristvey, A.G., Ross, D.S. & Kantor. G.F Deployment of Wireless Sensor Networks for Irrigation and Nutrient Management in Nursery and Greenhouse Operations. Proc. Southern Nursery Assoc. Res. Conf. 54: Lea-Cox, J.D Using Wireless Sensor Networks for Precision Irrigation Scheduling. In Problems, Perspectives and Challenges of Agricultural Water Management, Dr. Manish Kumar (Ed.), ISBN: , InTech, Available from: Lichtenberg, E., J. C. Majsztrik and M. Saavoss Profitability of Sensor-Based Irrigation in Greenhouse and Nursery Crops. HortTechnology 23: Majsztrik, J. C., E. W. Price and D. M. King Environmental Benefits of Wireless Sensor-based Irrigation Networks: Case-study Projections and Potential Adoption Rates. HortTechnology 23: Raviv, M., Lieth, J.H. & Wallach, R Effect of Root-Zone Physical Properties of Coir and UC Mix on Performance of Cut Rose (cv. Kardinal). Acta Hort. 554: Ross, D. S., Irrigation System Audits. In: Water and Nutrient Management Learning Modules. J. D. Lea-Cox, D. S. Ross. and C. Zhao. (Eds.). University of Maryland, College Park, Maryland. P Smith, K.A. & Mullins, C Soil and Environmental Analysis: Physical Methods. 2nd Ed. Marcel Decker, New York, NY. 352

362 Smajstrla A.G. & Harrison, D.S Tensiometers for Soil Moisture Measurement and Irrigation Scheduling. Univ. Fl. IFAS Ext. Cir. No p. Topp, G.C Time-Domain Reflectometry (TDR) and its Application to Irrigation Scheduling. Adv. Irr. 3: van Iersel, M.W., Dove, S. & Burnett, S.E The Use of Soil Moisture Probes for Improved Uniformity and Irrigation Control in Greenhouses. Acta Hort. 893:

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364 Chapter 19 Fertility Management Andrew Ristvey, Extension Specialist, Nutrient and Water Management Introduction Since soilless substrates contain little to no native nutrients, fertilizers are applied to overcome deficiencies and optimize growth. By far, the most important plant growth factor is water. Nutrients move with water in the substrate and in the plant. Irrigation management is the primary concern and is the basis of nutrient management. This chapter will discuss nutrients and plant fertility. Although specific recommendations for nutrient solutions are not given, this chapter will assist in making the right choices for nutrient applications. With nutrient management regulations and more importantly the price of fertilizer increasing, more judicious applications of fertilizer are necessary. Plant Nutrition Introduction There are seventeen recognized elements that are considered essential for plant growth. Three of these are non-mineral elements that are acquired from the air and water; Carbon (C), Oxygen, (O) and Hydrogen (H). The others are considered mineral nutrients (Tables 19.1 and 19.2). There are some nutrients which will be addressed in this chapter that are not considered essential either because they are not needed by all plants or that they provide an extra function beyond growth and reproduction, e.g. pest or pathogen resistance. Arnon and Stout (1939) listed three criteria for essential for plant growth: 1. Required for the completion of the life cycle of the plant. 2. Must not be replaceable by another element. 3. Must be directly involved in plant metabolism, that is, it must be required for a specific physiological function. An additional criteria should be added: 4. The element must be required by a substantial number of plant species. These rules are general and new knowledge of plant nutrition increases. In ideal circumstances, plant growth may be limited only by the speed in which biological and genetic processes can take place. However, in the natural environment plant growth is limited by many factors including light, water, and temperature, which may constrain growth before nutrition plays a role. Justus von Liebeg, a nineteenth century German chemist developed his Law of the Minimum principle, which states that plant growth progresses to the limit imposed by the resource in least relative supply. Liebig suggested that the yield potential of a crop is like a barrel with staves of unequal length (Fig. 19.1). The staves represent resources. The capacity of the barrel is limited by the length of the shortest stave and can only be increased by lengthening that stave. When that stave is lengthened, another stave becomes the limiting factor. 355 Figure 19.1 Law of the Minimum Principle

365 The truth is that plant nutrition is far more complicated. What does least relative supply suggest? In a plant, one nutrient may be needed in far greater supply than another. A nutrient may be in greater supply than any other nutrient, but is needed by the plant in such quantity, that the amount available is relatively insufficient for growth. Non Mineral Nutrients Carbon serves as the main building block for all organic compounds and life itself. Carbon in the form of carbon dioxide is reduced and converted to carbohydrates during the process of photosynthesis. Carbohydrates serve as a the primary storage medium. The ability to synthesize amino acids, nucleic acids and lipids from those carbohydrate reserves are processes found only in plants and some bacteria. Carbon is the most abundant element in plants. Oxygen serves as an important factor during the process called respiration, where carbohydrates and other carbon containing compounds are broken down for energy. Oxygen is also a main constituent of organic compounds. Oxygen is obtained from the atmosphere and from the break-down of water during photosynthesis. Hydrogen is used for carbohydrate production both as a primary constituent and cofactor for production. Hydrogen is formed during photosynthesis where it is split from water. Hydrogen, oxygen and carbon are considered non-mineral nutrients because they are derived from the atmosphere or water. They are needed by plants in large quantities compared to other nutrients. Mineral Nutrients There are now fourteen recognized essential mineral nutrients. All nutrients are elements. Nickel was most recently added to the list. These nutrients are derived either from the soil or atmosphere (as in nitrogen) and enter the plant through the roots and in some cases the leaves. The mineral nutrients are classified as either macronutrients or micronutrients. Macronutrients are further classified into primary and secondary nutrients. Macronutrients are required in far greater amounts than micronutrients. There is a range of concentrations of many of the essential nutrients Figure 19.2 General Example of Concentration Ranges of Several Nutrients Found in Plant Leaves Macronutrients are on the left and micronutrients are on the right. Note the link between macro and micronutrients. A concentration of 0.02% is 200 ppm. Dark shaded portion of bars represents deficiency to just sufficient concentrations. (Handrek and Black, 1994). as they exist in plant leaves (Fig. 19.2). The dark shaded portion of the bars represents deficiency. For example, on average, nitrogen is sufficient at 2%. Below 2% nitrogen becomes deficient and above 2% where the bar is light-colored, concentration is in an acceptable range. Macronutrients Six essential nutrients are considered macronutrients. They are required by plants in relatively large amounts at levels from 10 to 5,000 times greater than those of many micronutrients. Macronutrients are

366 divided into primary and secondary macronutrients. Primary macronutrients include nitrogen, phosphorus, and potassium. These are nutrients which are typically limiting to plant growth and are applied to soil as fertilizer. Secondary macronutrients are those that are typically found in soil at relative concentrations to satisfy plant growth. However, these and other nutrients need to be applied with organic substrates. Nitrogen is the most important of the nutrients applied and is the basis of fertility programs. Nitrogen has two forms, nitrate and ammonium, that are important as a plant nutrient. Nitrogen is very reactive and is affected by many factors including microorganisms. Additionally, the two forms of nitrogen can be changed by biological processes to atmospheric nitrogen (denitrification) or become part of the biology (immobilization) of the substrates inside the containers. Micronutrients Micronutrients or trace elements are those elements that are required by the plant in quantities from 10 to 5,000 times less than macronutrients. There are eight recognized essential micronutrients. Micronutrients are mostly metals, except chlorine and boron (which is a metalloid), which are used for enzymatic processes. Fertility Management Management of fertilizers is based on many other aspects of the nursery or greenhouse apart from what is in the fertilizer bag. First, irrigation water quality will have an effect on the availability of nutrients in the substrate, specifically, the alkalinity. As cited in the chapter on substrates chapter (page 230), alkalinity will affect the substrate ph and in turn, nutrient availability. Nutrients are affected by ph in organics substrates (Fig. 21.3). The thicker the black line, the more available a nutrient. Note that iron s line is very thin at high ph and decreases in thickness as ph increases. The ph for optimum nutrient availability is between 5.4 and 6.2 and most plants should be grown within this ph range. There are however some plants that require ph greater or less than the suggested range. Fertilizer Forms Various nutrients are available in the form of fertilizers (Tables 19.1 and 19.2). Regardless of source, the same nutrient is assimilated by the plant. For instance, organic nitrogen sources contain ammonium nitrogen. The same ammonium is assimilated in a non-organic mineralized source like ammonium sulfate. Non-organic or conventional fertilizers come in a variety of forms. The three numbers on a fertilizer bag indicate the % ratio of nitrogen, phosphate and potash, or N, P 2 O5 and K 2 O. The second and third numbers are not specifically phosphorus (P) and potassium (K). Phosphate is approximately 44% phosphorus and potash is approximately 83% potassium. Keep this in mind when calculating P and K rates. The nitrogen form will also change the ph of the substrate. The decision to use specific fertilizers should be based on irrigation water quality, specifically, the alkalinity of the irrigation water. The different types of commercially available fertilizers can change substrate ph based on their potential acidity or 357 Figure 19.3 The Effects of ph on Nutrient Availability in Soilless Organic Substrates Nutrient availability is depicted with increasing ph by the thickness of the back lines. The thicker the line, the more available the nutrient is.

367 basicity (Table 19.3). The example is not to be taken literally, but to provide an illustration of how acidifying an ammonium based fertilizer can be. Potential acidity is the amount (lbs) of calcium carbonate to neutralize one ton of the acid fertilizer. Simply, the higher the % of ammonium (NH 4 ), the more calcium carbonate would be needed to neutralize it. For example, if 100 lbs of is used, it would need 85 lbs of calcium carbonate to neutralize the acidity. Additionally Table 19.3 shows fertilizers with potential basicity, the use of which is equivalent, by weight, to adding calcium carbonate. For example, if 100 lbs of is used, it would be equivalent to adding 21 lbs of calcium carbonate. Note that even though some of the fertilizers with relatively high ammonium concentrations are neutral (see ), they are a source of calcium. With water alkalinity of less than 50 ppm, consider using fertilizers with potential basicity. With alkalinity above 150 ppm, consider fertilizers with potential acidity. In any case, monitoring the substrate ph is necessary. Some believe that the nitrogen form will dictate the growth of the plant, specifically, internode length. New research is showing that ammonium does not increase internode length and the use of nitrate fertilizers is not the reason for compact plants, rather low phosphorus in nitrate fertilizers may be the reason for compact growth. Do not use nitrate solely to control plant growth if high alkalinity water is present. Find ammonium based fertilizers with very low phosphate contents such as Phosphorus was always associated with improving root growth, but research has proven that incorrect. It is recommended that low phosphorus fertilizers with N/P 2 O 5 ratios higher than 2 to 1 (e.g ) be used. 358

368 Table 19.1 Formulas, Molecular Masses, and Compositions of Common Fertilizers Used for Macronutrient Fertility Adapted from Handrek and Black, 1994 Compound Formula Percent of Elements (Sources of major nutrients) Ammonium chloride NH 4 Cl N, 26 Ammounium nitrate NH 4 NO 3 N, 35 Ammonium sulfate (NH 4 )2SO 4 N, 21.2; S,24.3 Calcium carbonate (limestone, CaCO 3 Ca, 40.0 calcite) Calcium chloride CaCl 2.6H 2 O Ca, 18.3 Calcium hyrdoxide (slaked lime) Ca(OH) 2 Ca, 54 Calcium nitrate Ca(NO 3 ) 2.4H 2 O Ca, 17.0; N, 11.9 Calcium sulfate (gypsum) CaSO 4.2H 2 O Ca, 23.3; S, 18.6 Diammonium phosphate (NH 4 ) 2 HPO 4 N, 21.2; P, 23.5 Dicalcium phosphate CaHPO 4.2H 2 O Ca, 23; P, 18 Di-potassium phosphate K 2 HPO 4 K, 44.9; P, 17.8 Dolomite CaCO 3.MgCO 3 Ca, 21.7; Mg, 13.2 Magnesium carbonate (magnesite) MgCO 3 Mg, 28.8 Magnesium nitrate Mg(NO 3 ) 2.6H 2 O Mg, 9.5; N, 10.9 Magnesium sulfate (epsom salts) MgSO 4.7H 2 O Mg, 9.9; S, 13.0 Monoammonium phosphate NH 4 H 2 PO 4 N, 11.8; P, 26 Monocalcium phosphate Ca(H 2 PO 4 )2.H 2 O Ca, 16; P, 24.6 Phosphoric acid H 3 PO 4 P, 31 Potassium chloride KCl K, 52.4 Potassium dihydrogen phosphate KH 2 PO 4 K, 28.7; P, 23.5 Potassium nitrate KNO 3 K, 38.7; N, 13.8 Potassium sulfate K 2 SO 4 K, 44.9; S, 18.4 Sodium nitrate NaNO 3 N, 16.5 Superphosphate: single triple P, 9; S, 11; Ca, 21 P, 20; Ca, 23.6 Tetra-potassium pyrophosphate K 4 P 2 O 7.3H 2 O K, 40.7; P, 16.1 Urea CO(NH 2 ) 2 N,

369 Table 19.2 Formulas, Molecular Masses, and Compositions of Common Fertilizers Used for Micronutrient (Trace Elements) Fertility Adapted from Handrek and Black, 1994 Compound Formula Percent of Elements (Sources of trace elements) Ammonium molybdate (NH 4 ) 6 Mo 7 O 24.4H 2 O Mo, 53 Boric acid H 3 BO 3 B, 17.5 Copper sulphate CuSO 4.5H 2 O Cu, 25.4 Iron (ferrous) sulphate FeSO 4.7H 2 0 Fe, 20.1; S, 11.5 Manganese chloride MnCl 2.4H 2 O Mn, 27.7 Manganese sulphate MnSO 4.5H 2 O Mn, 22.8 Manganese sulphate MnSO 4.H 2 O Mn, 32.4 Manganese sulphate MnSO 4.4H 2 O Mn, 24.6 Sodium borate (borax) Na 2 B 4 O 7.10H 2 O B, 11.3 Sodium molybdate Na 2 MoO 4 Mo, 46.6 Sodium molybdate Na 2 MoO 4.2H 2 O Mo, 39.6 Zinc sulphate ZnSO 4.7H 2 O Zn,

370 Table 19.3 Commercially available fertilizers that either acidify or increase substrate ph based on potential acidity or basicity Fertilizer (N-P 2 O 5 -K 2 O) NH 4 (%) Potential Acidity (lb calcium carbonate to neutralize per 100 lb of fertilizer) 361 Potential Basicity (lb calcium carbonate equivalent) acid Generally, increasing percent of ammonium increases potential acidity or the amount of calcium carbonate needed to neutralize a ton of the fertilizer. Potential basicity is the amount of equivalent calcium carbonate used per ton of fertilizer. Note that some fertilizers have a percent of ammonium yet have little potential acidity because of the calcium content (Adapted from Nelson, 2002). For instance, a is suitable for optimum plant growth and recent research suggests that even lower P rates can be used, especially to prevent stem stretch and for non-flowering foliage plants. Some growers successfully utilize with an N/P 2 O 5 ratio higher than Fertility can be changed based on the plant s growing cycle. Use very low P formulations during vegetative growth and change to higher P formulations right before flower formation. Do not use superphosphate as an amendment as this and all forms of soluble phosphorus leaches quickly from organic soilless substrates. Ca (%)

371 Other than N-P-K There are a variety of N-P-K formulations in fertilizers (Table 21.3). Commercial fertilizers may or may not come with additional nutrients other than N, P and K. The complete fertilizer will have all of the essential macro- and micronutrients nutrients needed for a plant s life cycle. There are a variety of fertilizers that offer different blends of nutrients other than N, P and K. These blends are formulated to give a variety of choices depending on the plants grown and the quality of the irrigation water. For example, a Cal-Mag fertilizer has above average concentrations of calcium and magnesium. In combination with high nitrate, the fertilizer can have high potential basicity. With more ammonium, the same can have a relatively low potential basicity. Some growers have needed to supplement these complete fertilizers with extra micronutrients, like iron or boron, when fertilizing at low rates. It is possible that in this situation, substrate or irrigation water chemistry negatively affects micronutrient availability. Supplements increase the concentration of micronutrients to overcome inhibitive effects. Additionally, the plants being grown may require specific nutrition (Fig. 18.2). For example, zonal geraniums require a ph of between 6.3 and 6.5 for optimal growth. If alkalinity is low in the irrigation water, a fertilizer with relatively high potential basicity, containing low ammonium and/or extra calcium and magnesium can be utilized. Water Soluble Fertilizers Application of soluble fertilizers through irrigation is called fertigation. It is the most widely used application method in greenhouses. Fertigation can be an efficient method for delivering nutrients to the plant because the application rate and delivery can be adjusted based on plant needs. However, fertigation can be very inefficient if care is not taken to apply irrigation directly to the plant or if injection equipment is not calibrated. It is essential that careful attention is paid to irrigation management, injectors are calibrated and leaching fraction is minimized to reduce nutrient runoff. The present best management practice recommendation is no more than a 15% leaching fraction. Stock Solutions The most efficient method of applying soluble fertilizers is through an injection system using concentrates or stock solutions. When mixing fertilizers from scratch, it will be necessary to have two or more injection systems. Certain nutrients like calcium will bind with phosphorus and the resulting calcium phosphate will become insoluble and unavailable for plant use. Fertilizer components containing calcium and magnesium should be mixed separately from components containing phosphorus and sulfate. Developing soluble mixtures may be less expensive but can be complicated from the standpoint of choosing the correct types of fertilizers and the amounts to mix together. A knowledge of chemical formulas and chemistry is needed. Use Tables 19.1 and 19.2 to assist with determining what fertilizers are available and the amounts of each constituent nutrient contained. North Carolina State University has a downloadable program (FERTCALC) to assist in calculating the right amount of fertilizer to add to the stock solutions. The fertilizer rates are merely a suggested range and may differ between species and growth phase (Table 19.4.) For instance, poinsettias may require no fertilizer during propagation and gradual increases in nitrogen rate from 100 ppm during the initial growth phase to between 200 and 300 ppm during the rapid growth phase, back to 100 ppm as plants enter the flowering phase. Other nutrients, like calcium and magnesium, are usually needed to supplement the fertilizer regime. 362

372 Table 19.4 Suggested Rates for Fertilizing Different Crop Types (ppm N) Plant Type Feed Program (ppm N) (Constant) Feed Program (ppm N) (Twice Weekly) Plugs Bedding Plants and Annuals Woody Plants Calculating Parts per Million Recommendations for applications of liquid fertilizer, chemical growth regulating compounds, and rootpromoting compounds appear in parts per million (ppm). Accurate applications can be made only if the grower has a working knowledge of how to make some basic calculations. Parts per million refers to the concentration of a material for any specific unit of weight or volume (Table 19.5). For example, one purple flower growing among 999,999 white flowers would represent.0001 percent of the flower colors or 1 part per million. Growers use a rule of thumb (though it is not scientifically accurate) that 1 ounce of material in 100 gallons of water is equivalent to 75 ppm. Use this rule of thumb to calculate fertilizer applications. Example: A grower wants to apply 200 ppm nitrogen to a salvia crop. The soluble fertilizer is How much should be dissolved per 100 gallons of water? Solution: 1 ounce per 100 gallons of water = 75 ppm 200 ppm divided by 75 ppm = ounces supplies 200 ppm The fertilizer is = 20 nitrogen 5 ounces of = 1 ounce N (20% of 5) 2.66 x 5 = 13.3 ounces of in 100 gallons of water to give 200 ppm N to the crop Mixing Fertilizers To obtain a desired parts per million (ppm) at the water hose, use the following to mix the stock solution: (proportioner ratio): 1 x (desired ppm) x 1.35 = ounces per gallon stock solution (%) nitrogen 100 Example: You have a 20% N fertilizer and a 1:100 injector You desire 200 ppm at the water hose. How many ounces of fertilizer do you add per gallon in the stock tank? 100 x 200 x 1.35 = 13.5 oz fertilzer per gallon water To obtain an unknown ppm at the water hose when adding a known fixed amount of stock solution: (%) nitrogen x (oz)/gal stock x 100 = ppm N at hose (proportioner ration): Example: You have a 15% N; a 1:100 injector; and someone has put 18 ounces of fertilizer per gallon in your stock tank. What is the ppm N coming out of the hose? 15 x 18 x 100 = 200 ppm N at end of hose

373 Tables 19.5 Injection Ratios and Nitrogen Concentration for Constant Feeding Ratio 30% Formula a 25% Formula b 100 ppm N 150 ppm N 200 ppm N 100 ppm N 150 ppm N 200 ppm N 1: : : : : : : : : Ratio 20% Formula c 15% Formula d 100 ppm N 150 ppm N 200 ppm N 100 ppm N 150 ppm N 200 ppm N 1: : : : : : : : : a e.g., b e.g., , , c e.g., , , d e.g., , , Controlled and Slow Release Fertilizers Controlled release fertilizers (CRF) have become a popular method of fertilizing plants from the standpoint of labor and efficiency. These fertilizers are coated with materials which make them slow to release and regulate their release rates. In most cases, these fertilizers have improved plant fertility management because nutrients are made slowly available to plant roots. The release of nutrients may not be in tune with plant requirements. Popular controlled release fertilizers are coated with either plastics, resins or polymers that permit water to enter the prill to dissolve nutrients and ready them for release. Release rates are dependent upon the specific coating material and temperature. Since temperature is often uncontrollable at certain times of the year, there is little that is controlled about the way nutrients are released. High temperatures will increase the rate of release, regardless of the labeled release rates which are typically tested between 65 and 77 F, depending on the manufacturer. They tend not to release when temperatures are cooler and, in many cases, when the plants need the nutrients. They release when temperatures are very warm resulting in salt loading in containers. These fertilizers are typically incorporated into the substrate or placed on top of the substrate. Fertilizers tend to release quicker when incorporated because of consistently higher temperatures within the container as opposed to when being on top of the substrate. 364

374 If fertilizer has been incorporated in the substrate, utilize the substrate as soon as possible. Do not allow the substrate to sit in large piles where they may begin to compost. The heat generated within the pile will quicken the release of the fertilizer in the prills. Salts will accumulate in the substrate and, upon use, may burn plant roots. Before using a substrate that has been stored, check the electrical conductivity. If the electrical conductivity is above 2.5, leach the substrate or irrigate the plants immediately upon potting. Monitor the substrate electrical conductivity for the next few days. In some cases nutrients from CRF s may be released immediately because of broken prills, imperfect coating, or from uncoated nutrients added for an initial quick release. The degree of this release can be easily checked by placing some prills in water and taking electrical conductivity measurements two or three times in a 24 hour period. Some growers, especially those who grow plants in greenhouses, prefer to limit CRF use because greenhouse temperatures can become very warm inside, promoting release of nutrients to quickly. Use of CRF s in greenhouses should be done with caution and constant monitoring of substrate salts is necessary. Slow release is another form of nitrogen based fertilizers. These types of fertilizers are released by hydrolysis (dissolved by water) or by microbial degradation. They include: Sulfur Coated Urea similar to CRF s the thickness of the sulfur coating determines nutrient release by water absorption. Urea formaldehydes release based on microbial degradation. Isobutydine diurea (IBDU) release based on hydrolysis which is affected by substrate moisture and ph. These forms of fertilizers are urea or ammonium based and are not recommended to be used in greenhouse culture because of the danger of ammonium toxicity. When utilizing these types of fertilizers, monitor substrates and check plants for ammonium toxicity. A new set of management skills are needed for these fertilizers. Substrate monitoring is essential for plant health when utilizing these CRF fertilizers. Advantages of using CRFs: Can minimize nutrient loss and runoff if manual watering is used Can minimize nutrient loss from leaching from graduate nutrient release rates Disadvantages of using CRFs Release of nutrients are not constant because of fluctuations in temperature and moisture in the substrate. Release of nutrients may not coincide with plant needs because of inconsistent nutrient release due to the above factor. Application Methods for Controlled Release Fertilizers There are two methods (incorporation and top dressing) for controlled release fertilizer application. Each has benefits and drawbacks (Table 21.7). Incorporation Controlled release fertilizers can be incorporated into the substrates, however a mixing device is needed to assure uniformity of distribution. This method is considered a best management practice since fertilizer is 365

375 contained within the substrate and there is little chance for loss from spilling. There is, however, a danger for quicker release rates because of consistently higher temperatures and moisture within the substrate. As noted above, substrate temperatures within the container have been measured well above the labeled release temperature for CRF s, therefore there will be times when excessive nutrient release will occur beyond the plant s ability to assimilate. Nutrient salts will build up in the container. Therefore, monitoring is essential for plant root health. Do not allow substrates with incorporated fertilizer to sit unused. Nutrient release will occur and plant roots will be damaged by excessive salts. Top Dress Fertilizers are placed on the top of the surface of the container. This method is utilized when plants are held an extra season and there is no intention of repotting. If using plug trays or similarly small sized containers when top dressing, it will be difficult to obtain even distribution of fertilizer. Soluble fertilizers applied through an irrigation system may be considered instead. When top dressing containers, use the manufacturers recommended rates, usually based on container size. The rates are suggested in ounces or grams and typically the manufacturer will suggest a volume that will be close for applying the recommended weights. For instance, 1/4 cup will equal 61 grams. Note that a medium rate of CRF will be sufficient for most crops. 366

376 Table 19.6 Suggestions and Precautions for Controlled Release Fertilizer Use Method Advantages When Precautions Management Incorporate Considered a Best Management Practice. When adding other amendments or before planting. Mixing machines may damage prills making nutrient salts immediately available. Minimize labor of applying fertilizer. Use piles of substrate quickly and do not let them sit for more than a week or so. Prills will release nutrient salts within the pile. Nitrogen may be depleted even though you have high EC. Incorporated prills will tend to release quicker especially during hot periods. Monitor substrate for EC before planting. Do not put plants in substrate with an EC higher than 3. Substrate must be irrigated to reduce EC to below 3 before planting. Monitor substrate for EC before planting. Do not put plants in substrate with an EC higher than 3. Substrate must be irrigated to reduce EC to below 2 before planting. Continue to monitor or test substrate in lab for N. Nutrients (especially N) may have depleted. May need additional fertilizer. Monitor substrate EC. Should be between 0.5 and 1 ds/m. If above 3 ds/m, you must irrigate. Check EC again. Leach if EC are still not below 2 ds/m. Maintain high moisture levels in substrate after. Top Dress Can be applied as additional nutrients if necessary. Can be applied at any time. If holding plants for another season or overwintering. If additional nutrients are needed in the middle of a cycle. Not recommended to top dress plug trays and cell packs. Rely on soluble feed. Take care to keep container upright as to not spill CRF. Apply rates according to manufacturer s recommendations, usually not more than medium rate. Do not broadcast prills, apply to each individual container. Minimize leaching by continually monitoring substrate. Prevent pots from knocking over and losing prills on ground. Take care when hand watering to prevent splashing prills out of container. Monitor substrates 367

377 Management of High Electrical Conductivities (ECs) Leaching is the inevitable solution to high electrical conductivities in your substrate. If you have EC s that are above 2.5 ds/m early in the day, irrigation to container capacity will be necessary to dilute the salts. Monitor after irrigation. If EC s have not decreased, continue irrigation until you have water coming out the bottom of the pot (leaching). Continue to monitor by taking pour through samples so not to over-leach. EC is only a measurement of salts in solution and does not tell which salts are available. Use EC measurements only as a guide, and do not rely on them to tell you how much nitrogen or phosphorus is available. This recommendation is especially true if a substrate with incorporated fertilizer has been sitting in a pile for a couple weeks or longer. The nitrogen could have been completely used by microorganisms as they composted the substrate. A high EC reading may occur because of the other salts in the fertilizer which without nitrogen, are useless to a plant. Selection of Fertilizer There are many factors to consider when selecting a fertilizer for a nursery or greenhouse. The cost is actually less important than the quality, i.e. nitrogen source for acidifying, primary macronutrient balance, and micronutrient content. Factors like plant selection and irrigation water quality will determine what is used. In some operations a one fits all approach may work, and in others the plants grown will require different formulations, even different fertilizers throughout the cycle of the crop. Some fertilizer manufacturers will custom blend fertilizers and may offer a monitoring package to ensure that the product is being utilized efficiently. Some slow release fertilizers offer blends of different release rates to compensate for low temperatures common during spring. Manufacturers want your business so be demanding. Use of Organic Fertilizers or Composts The addition of organic fertilizers or composts to your substrate may interest organic producers. The most critical issue about the use of organic fertilizers is the physical and chemical consistency of the product each time. Soluble organic fertilizers injected through the irrigation system may clog emitters. Be aware that you may need to flush and clean the irrigation system. Make sure the materials used are consistent in nutrients supplied. Have your composts and organic fertilizers tested regularly at a certified laboratory. The amount of nitrogen in organic fertilizers is usually low and the N/P 2 O 5 ratio is also usually low which means more phosphorus may be applied than necessary. Since these materials can contain nitrogen and phosphorus, Maryland growers will need to keep track of their additions for nutrient management planning. References Arnon, D. J., and P.R. Stout The essentiality of certain elements in minute quantity for plants with special reference to copper. Plant Physiology. 14: GroCalc Greenhouse Growers Software FertCalc software download. floriculture/software/fertcalc.htm. Accessed November Handreck, K.A. and N.D. Black Growing media for ornamental plants and turf. 3rd ed., University of New South Whales Press. Randwick, Australia. 448p. J. D. Lea-Cox, Fertilization Strategies. In: Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. J.D Lea-Cox, D.S. Ross and C. Zhao (eds.). University of Maryland, College Park, Maryland. Published online at Mills, H.A., J.B. Jones, Jr Plant analysis handbook II: A practical sampling, preparation, analysis and interpretation guide. MicroMacro Publishing Inc. Athens, GA. 422p. Nelson, P.V Greenhouse operation and management (6th ed.). Prentice Hall, NJ. 368

378 Chapter 20 Fertilizer Injection or Fertigation Chuck Schuster, Extension Specialist David S. Ross, Professor and Extension Agricultural Engineer Andrew Ristvey, Extension Specialist Introduction Fertigation, the addition of fertilizers to irrigation water, has been a common practice for many years. In many situations it is more practical to apply a liquid fertilizer through the irrigation system as the plant requires nutrients than to try to apply it preplant in the substrate or as a sidedress later. With fertigation, the application of liquid feed can be timed according to plants nutrient needs. Fertigation offers growers greater control and flexibility than traditional fertilization. Growers need to exercise caution, however, when practicing fertigation. Applications of liquid fertilizer are more likely to increase the risk of nutrient runoff than applications of slow-release fertilizer. Runoff is one consideration that must be taken into account. Check the risk of runoff into surface waters from your site. Several terms used in fertigation need to be defined. The device that puts the fertilizer solution into the irrigation water is commonly called the injector. However, a more descriptive term is proportioner. A proportioner is a mechanical device that introduces concentrated fertilizer solution (stock solution) into the irrigation pipeline. Stock solution is the concentrated mixture of fertilizer and water to be diluted by the proportioner. The proportioner operates at a preset dilution ratio, which is defined as the volume ratio of stock solution combined with water to produce a diluted solution, the irrigation water. A proportioner set at a 1:15 ratio will add 1 gallon of stock solution to 14 gallons of water to produce 15 gallons of irrigation water. In this case, for example, irrigation water with 200 parts per million (ppm) of nitrogen (N) would consist of a stock solution of 3,000 ppm of N. When injecting fertilizer into an irrigation system, be careful not to contaminate the water supply. A check valve must be located between the irrigation pump and the point of injection to prevent backflow of the fertilizer solution into the water supply. To reduce the chances of leakage past the check valve, an air vacuum breaker is installed on the pump side of the check valve. We recommend that you install a lowpressure drain with the vacuum breaker. This is the simplest form of backflow preventer, but one that can save accidental pollution of the water supply. More elaborate units are required to protect potable water. Several types of proportioners (injectors) are available; all will place stock solution into irrigation water. All the proportioners differ in the way they work and in their accuracy. A bladder tank type unit represented by a Gewa tank works in small batches. The stock solution is placed in the bladder or bag inside a tank. Part of the irrigation water passing through a proportioner valve on the unit directs water into the tank around the outside of the bladder, causing stock solution to be pushed through a valve into the irrigation water. The process continues until the bladder collapses because it is empty. The bladder tank, which has been common in greenhouses for many years, can be attached to a watering hose (Fig ). Another proportioner is the venturi device, a pressure differential system that creates a suction to pull the stock solution into the irrigation line. The venturi functions by creating suction (negative pressure) inside; the pressure is high on the input side and lower on the output side. The venturi device contains a 369

379 Figure 20.1 Using Proportioners For Fertilizer Applications The Gewa proportioner illustrates the bladder tank system. Water enters the tank to push the chemcial out of hte bladder and into the irrgiation line. (Courtesy Gewa and Hermann A. Wirth, distributor) 370

380 small-diameter passage (restriction) that causes irrigation water to speed up and pass through the device at high velocity. A small inlet opening into this restricted zone connects to a hose from the stock solution. Water passing at high velocity through the restriction creates a vacuum at the small inlet and fertilizer solution is drawn in. A valve may be placed on the stock solution hose to regulate its flow. This device requires a considerable pressure drop across the venturi to make it work. Because much pressure energy is lost in the venturi s flow restriction, the pressure is much lower on the discharge side. The remaining pressure must be high enough to operate the emitters or sprinklers of an irrigation system. Extra pressure capacity is required from some source to make the venturi device function. Because this method is more difficult to control than other methods, uniformity of the final solution may vary (Fig ). Adding the venturi injector into an existing irrigation system may cause problems with low pressure in the irrigation system. As noted above, the pump must have extra pressure capacity to properly operate the venturi device. Sometimes the venturi is installed on a pipe path parallel to the irrigation line. Clear Figure 20.2 Venturi Injection A venturi injection device works on a differential pressure principle. The venturi is mounted in parallel bypass when water flow exceeds injector cpapacity. (Courtesy of Mazzei Injector Corptoation) irrigation water can be used through the straight pathway or valves can be turned to direct the water into the parallel bypass. Sometimes the venturi device is not large enough to handle all of the flow so water travels along both paths. The valve on the irrigation line is partially closed to direct water onto the parallel bypass path and to restrict the water flow to cause a pressure differential. Another method for providing the extra pressure to operate a venturi device is to add a centrifugal booster pump to the parallel bypass path to create the higher pressure needed for the pressure differential. This additon allows the regular irrigation pump to be a more economical size. Pressure gauges are recommended when using a venturi injector to achieve repeatable application situations. Positive displacement proportioners use a piston or diaphragm pump to inject the fertilizer stock solution into the irrigation line. Two types of these units are in common use. In small greenhouses, a water-powered 371

381 pump is used. In larger systems, an electric motor or a gas or diesel engine may be used to operate the pump. The advantage of the water-powered units is that the injector speeds up or slows down according to the flow of irrigation water, which maintains uniformity. The water-driven piston is directly connected to the fertilizer pump piston. Water drives one piston, which is linked to another piston (Fig. 20.3). The small water-powered units are available in several sizes; units can be portable or permanently installed. These units can be mounted to pass through all the irrigation water or installed in a parallel bypass loop to operate on part of the irrigation flow. Irrigation systems with constant flow rates work best for consistent results. The proportioner is selected by the irrigation flow rate; each size of proportioner is used for a range of irrigation flow rates. Dilution ratios are usually easy to change. Figure 20.3 Positive Displacement Proportioner Basic concept of a positivie displacement proportioner. A fixed amount of chemical is injected into a fixed amount of water as each piston makes a cycle. Caution - Do not assume that home stock solution recipes are correct. The size of the bag or the composition of the fertilizer mix may have changed but not the recipe. Errors have been found in recipes handed down from one generation to another, and the application rates have been different than expected. To test the nutrient solution, take water samples toward the end of the injection period to ensure that all parts of the system are carrying the nutrient-enriched irrigation water. Water moves at various speeds in different parts of a pipeline system. The nutrient-laden water will take more time to reach the last lateral line off a submain or manifold. If sampling takes place too early, you might end up sampling the water before the nutrients have reached the end of the system. Calibration of the proportioner enables you to verify if the amount of stock solution injected is correct for the amount of irrigation water that passes through the system. The easiest way to calibrate the unit for checking the dilution ratio is to place a measured amount of stock solution into a container at the input to the injector. Find a large enough reservoir to catch and measure the output of irrigation water plus the added stock solution for a short period, or use the before and after readings on the flow meter, if the irrigation system has one and it is working well. The goal is to measure the water that passes through the irrigation system while the stock solution is being pulled in by the injector. If the dilution ratio is 1:30, then 29 gallons of irrigation water should pass the injector while 1 gallon of stock solution is pulled in or pumped into the 372

382 irrigation line. Try to measure this carefully to confirm the accuracy of the proportioner. Make adjustments as needed to correct the injector. Electrical conductivity (EC) can be used to monitor an injector. For a given water supply and proportionermixed irrigation-fertilizer solution, there is an EC reading. The fertilizer is made of salts and therefore will have its own electrical conductivity when properly prepared. Mix carefully measured irrigation water and stock solution in the correct ratio (in a small batch) and check its EC several times. Record the average of these readings. Use the average reading as a guide when you test the irrigation water in the future. Be careful to determine if the EC meters function well for the range of values to be measured. Some fertilizer companies list testing guidelines, using EC readings, on the fertilizer bag. Remember that the clear irrigation water likely has an initial EC value of its own that is part of an overall mixture reading. Precision of the EC meter affects the accuracy of this method. Check to see if chemicals are compatible before mixing. More than one injector may be needed if several fertilizers are to be injected or if combining fertilizers at high concentration will cause precipitation. Have a competent laboratory test samples of your fertilizer-enriched irrigation water to be sure the concentration of nutrients is correct. Place the fertilizer injector before the filters in the irrigation system so that any chemical precipitates formed by the injected chemicals are caught by the filters and do not cause emitter or nozzle clogging. 373

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384 Chapter 21 Care and Calibration of Injector Pumps Chuck Schuster, Extension Specialist Introduction This section will cover how to care for and maintain fertilizer injector pumps or proportioners and discuss several methods of calibrating these pumps for effective and efficient application of nutrients and other materials on your plants. Proper care and calibration will prevent under or over application of nutrients and other treatments needed for appropriate plant growth. Injectors or proportioners are pumps which automatically mix dissolved concentrated materials like fertilizers or other chemicals into a solvent such as water. The material is injected into the water at a specific rate or ratio. For instance, at an injection rate of 1:50 the injector will pump 1 part of concentrated material into 49 parts water equaling a total of 50 parts of final solution. The concentration of the dissolved material can be by manipulated by adjusting the injection ratio setting. Often concentrations are expressed on a percentage basis or on a parts per million basis so it is important to know these units and some mathematical procedures to be able to calculate the correct injection rate. Parts of a Pump It is important to know the various parts of your displacement injector system (Fig. 21.1). Irrigation water flows from left to right. An external filter is necessary to filter any abrasive particles in the water before entering your pump. A check valve is placed in-line between the filter and the pump. This is a one-way valve. It only allows water to move in one direction (an arrow on the valve should point to the pump), and prevents any fertilizer water from reversing direction back into your water source. Located on the lower portion of the injector is the proportioner system which allows you to adjust the rate of your fertilizer injection. Within the body is the piston which moves with water flow. An internal filter can be found on this model. O-rings can be found throughout the injector. Piston Piston Internal filter Direction of flow Check valve O-ring Proportioner External filter Proportioner Figure 21.1 Parts of an Injector System 375

385 Routine Maintenance A poorly operating injector can over or under apply material which may waste material, money, or cause damage to the plants. It is therefore important to make sure that the injector is in good working order and is calibrated to assure a reliable concentration. There are several types of injector pumps and all have many working parts. Parts must be inspected on a regular basis (Table 21.1). 1.Filters, usually placed at the beginning of the hose located in your concentrate container, should be inspected for clogging daily. Many soluble fertilizers have some insoluble ingredients which may plug the filter, slowing or preventing concentrate from being injected properly (Fig. 21.2). Other filters seen on this model should be cleaned as frequently. Input water quality should be considered when selecting the filtering system used on the fresh water line prior to entering the injector pump. Frequent cleaning of filters can prevent flow rate problems. Figure 21.2 Concentrate Filter Check filter daily. It should be free of foreight material to allow for the free flow of conentrate through the screen 2. O-rings used to seal parts can tend to dry out and crack, creating leaks. The high salt or solvent concentrations can deteriorate O-rings and other rubber seals. They should be checked on a monthly basis. You can lubricate O-rings and seals with a silicon based lubricant but never use petroleum jelly (Vaseline) because it tends to dissolve rubber. Abrasive materials in suspension may cause wear to pistons and seals over time. 3. Stock tanks should be cleaned each time after being emptied to remove salts and insoluble materials that can build up over time. This material may be small enough to fit through strainers and cause internal wear of the injector. Tables 21.1 Maintenance Schedule for Injector System Daily Weekly Monthly Yearly Check filters * Check O-rings * Calibrate * Or at least 2x per year Stock tank * Before refilling Calibrating Injectors There are two methods for calibrating injectors; the Dilution-Ratio Method or the Electrical Conductivity Method. Each method is effective and relatively easy for ensuring that your injector is functioning properly and giving you the correct injection rate. The Dilution-Ratio Method: This method is the simplest and can be performed with the least amount of materials. The method calculates the fraction of injected liquid that flows into a known amount of clear water. 376

386 The materials you will need are: 1) Five gallon bucket 2) A measuring container with incremental volume measurements 3) An EC meter (Fig. 21.2) 4) Calculator To calibrate with the Dilution-Ratio Method 1. Place suction tube into measuring cup 2. Run injector to purge air bubbles 3. Fill measuring cup to capacity and note total volume 4. Turn on water to the rate used in fertilization 5. Start collecting output into five gallon bucket 6. Stop water flow when either a. the five gallon bucket is full, or b. the measuring cup is empty 7. Determine the amount used from the measuring cup or the amount collected in the five gallon bucket in gallons Use the following formula to calculate injector ratio: Injector Ratio = Gallons of Water Collected x 128 Ounces Per Gallon Ounces of Water Used From Measuring Cup Example: You have collected 5 gallons of water and use 10 ounces from the measuring cup 5 gal x 128 oz = oz The ratio is 1:64 Figure 21.3 An EC meter Electrical conductivity (EC) calibration requires an EC meter. The Electrical Conductivity (EC) Method: With this method you will need an electrical conductivity meter. Each type of fertilizer has a specific electrical conductivity based on the desired concentration you make. However, each type of fertilizer will have a different EC for the same application rate. You cannot use the same EC value for two different fertilizers even if you are mixing to the same concentration. For instance a at 200 ppm nitrogen will not have the same EC as a at the same rate. Most soluble fertilizers will have a table with dilution rates and corresponding EC for each rate. There are several accepted units for electrical conductivity. The most common is the mho (pronounced mō). This unit is commonly found of bags of soluble fertilizer as mmhos/cm (milli mho per centimeter which is one thousandth of a mho). However, another unit is the Siemen (pronounced Sē-men). It is often used with these units; ds/m (deci Seimen per meter) or ms/cm (milli Seimen per centimeter). There is no need to convert values between these units. 377

387 The materials you will need are as follows: 1. Electrical conductivity meter 2. Standard solution for calibration of meter 3. Plastic measuring cup To calibrate with the Electrical Conductivity Method 1. Run water for at least 5 minutes with fertilizer turned off 2. Collect sample of clear water in plastic measuring cup and measure electrical conductivity 3. Record measurement 4. Begin fertilizer injection and let run for at least 2 minutes 5. Measure conductivity of fertilizer solution 6. Subtract electrical conductivity reading for clear water from electrical conductivity reading for fertilizer solution 7. Record this number 8. Using label from manufacturer, check calculated reading to provided value 9. Adjust injector or concentration in stock tank accordingly 10. Re-test solution It is important to test the electrical conductivity of your clear water first because it has naturally occurring electrical conductivity. This clear water electrical conductivity value is subtracted from the electrical conductivity of the fertilizer solution to accurately define the electrical conductivity produced by the fertilizer alone. Using the fertilizer label, check the calculated electrical conductivity reading against the electrical conductivity value provided by the manufacturer. Adjust injector or concentration in stock tank accordingly. Once you have verified the injector ratio you can determine how much concentrated fertilizer (nitrogen in this example) is needed in a stock tank to deliver a certain concentration of material at a specific injection ratio with the following information: 1. The percent nitrogen in the fertilizer 2. Desired concentration of nitrogen in ppm (mg/l) 3. The size of the stock tank 4. Use a conversion factor of 75 which converts milligrams to ounces and liters to gallons Use the following formula to calculate amount needed in stock tank: ppm of N needed x injection ratio % N in fertilizer x Conversion Factor (75) 200 ppm x 100 = 13.3 oz / gal 20 x 75 Care and calibration of your fertilizer injectors is important for your plants and your greenhouse or nursery. In the long run, this management practice will save you time and money and give you piece of mind. Remember to keep records of your results each time you calibrate and perform maintenance. 378

388 Part 5 Greenhouse Structures and Environment Chapter 22 Chapter 23 Chapter 24 Chapter 25 Greenhouse Selection and Placement Greenhouse Growing Environment: Temperature and Humidity Greenhouse Systems Maintenance Greenhouse Substrates

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390 Chapter 22 Greenhouse Selection and Placement David S. Ross, Professor and Extension Agricultural Engineer Introduction A new or prospective greenhouse owner has important decisions to make when starting or expanding a greenhouse production system. Whether you are going to run a large or small operation, some of your most critical decisions will center on choosing a greenhouse that has high-quality glazing, an adequate and efficient heating system, a winter and summer cooling system, good internal air circulation, uniformly distributed and precisely supplied fertigation, and a computer or processor control system that maintains recommended temperature levels. The greenhouse structure may actually be the least costly item in the system; the environmental and materials handling equipment usually costs more than the structure itself. Materials handling equipment includes devices for mixing substrates, filling containers, and transplanting seedlings, plus the carts and conveyors for moving flats and containers around the growing areas and other laborsaving devices. Having all of these systems appropriately designed and installed significantly increases your chances for successful plant production. If you are expanding or planning to expand your operation, choose a well-designed gutter-connected greenhouse and a head house. Using a gutter-connected greenhouse instead of a series of single units of the same total area will save percent in energy costs. A large greenhouse will enable you to achieve labor and management efficiency. A well-designed and placed head house provides a work and storage area to support the plant growing (input) and plant selling (output) functions of the operation. In the head house the two functions must be separated; the flow of plants to the growing area must not interact poorly with the flow of plants going to market. The most significant expenses to keep under control are capital investment, energy, and labor. Maximizing profits requires that you are realistic about costs and that you keep your costs under control. Expected income must dictate the costs incurred. A high value crop produced several times a year will support a large investment. Producing only a fall and spring crop, however, may limit the kind of facility that you can afford. Although your production facility must provide a well-controlled environment, an energysaving cover (glazing), and labor-saving devices, your investment in the facility must take into account the expected income from the crop. You also need to consider the real cost of paying hired associates. Energy can quickly become the most significant cost factor for all operations whether they are large, small, efficient, inefficient or even a small hobby operation. Therefore, it is appropriate to emphasize energy as a major target for cost control. Unfortunately, beginning growers often ignore the real cost of labor and, even, the real cost of capital investment. Plant-growing sometimes starts as a hobby or as an inadequately planned venture capital activity. New growers sometimes purchase a greenhouse at a very low cost from a former grower or envision labor consisting of low-paid family members. 381

391 Free-standing or Gutter-connected New growers may ask, What style of greenhouse should I erect freestanding or gutter-connected? First, however, how large an enterprise are you planning? What crops will you grow? How many square feet of crops do you need for adequate income? Will your business be wholesale, retail, or both? For a new grower who wants to operate a productive unit while gaining experience, a 3,000- to 4,000-square-foot freestanding Quonset greenhouse is a good choice. For growers planning to have more than 20,000 square feet of greenhouse space, a gutter-connected structure is usually the best. If you are planning a space in the range of 10,000 to 20,000 square feet, a gutter-connected greenhouse is still likely the best choice. The greatest advantage of having a gutter-connected greenhouse as a production unit is ease of management: all crops and all laborers and the entire heating, cooling, and fertigation system is under one roof. When you enter one greenhouse, the entire crop or production unit is before you. With a series of small greenhouses, the manager must go into several greenhouses to check on watering, temperature, and the health and appearance of the crop and to handle all the elements necessary to managing a crop or labor force. Another advantage of a gutter-connected house is the ease of installing a retractable energy and shade screen. One automatically controlled screen can be used for both summer shading and winter heat conservation. While retractable screens can be added to a freestanding greenhouse, they are very costly and difficult to install and maintain. To evaluate the energy usage of a modest-sized operation, compare four freestanding 30-foot by 96-foot double-polyethylene greenhouses to a similar gutter-connected greenhouse, 120 feet by 96 feet with an 8-foot eave height. If the night set point is 60 F and the heaters are designed for an outside lowest temperature of 0 F, the four freestanding greenhouses will use 13,017 gallons of oil per year. The gutterconnected greenhouse will use 11,174 gallons, for a savings of 1,843 gallons. Adding an energy screen to the gutter-connected greenhouse can further reduce the oil consumption to 8,940 gallons, an additional savings of 2,235 gallons. Today, the recommended eave height is 12 feet; the additional height increases fuel costs about 10 percent but greatly improves the functionality of the structure. Gutter or Sidewall Height Greenhouses have risen in height from 8 feet to as high as 16 feet in recent years for several reasons. The added height offers valuable space for installing the following: at the top, a thermal blanket (heat curtain), a black-out curtain, and/or movable shade curtain; in the middle, hanging baskets on movable conveyors; and automatic boom watering systems underneath but above movable benches. Other combinations of equipment might use the space in these houses and the added height allows future flexibility. Another positive aspect of greenhouses with high ceilings is that heat rises. The heated air moves up above the plants and workers space and is drawn away by the ventilation system. The added height increases air volume for absorbing solar heat. The height adds only a little to the heating cost in winter, particularly for gutter-connected houses. Height works particularly well for naturally ventilated houses; if your greenhouse relies on natural ventilation, allow more vertical room for air movement. Historically, high houses and fan ventilation combinations have not been effective. Exhaust fans are still located to draw the air across the top of the crop. Open-Roof Greenhouses Problems of light reduction and ventilation have been solved by the adoption of a new style greenhouse structure. The open-roof style is being adopted by growers who use their house for growing through the 382

392 warm season of the year. The roof pivots at the gutter to open fully, so that the roof is positioned above the gutter when fully open. As the sun moves across the sky for a house oriented north-south, there is a period of time in midday when the crop receives full sunlight. At the same time there is no closed cover over the crop to trap the heat energy. Natural ventilation occurs and the crop temperature is nearly the same as ambient air outside the greenhouse. During summer storms or cold weather the greenhouse roof is in its closed position. Site Selection Because sunlight in the winter is most critical, make sure the site is free of any obstructions that will cast shadows on the greenhouse when the sun lies low in the sky during late December. Place the greenhouse away from the obstruction at a distance of at least 2.5 times the height of the obstruction. A slightly southsloping site positions the greenhouse well for receiving winter sunlight. A wind barrier on the north and west will lower the winter wind speed against the house and will help to reduce cold air infiltration. The site should have good drainage; having a location for a water retention pond helps to ensure some surface water management possibilities. Drainage is important for removing water from the roof and paved areas after heavy rains. Locate the site near electrical power, water, and telephone for utility hookup. A water source is very critical to the business; assess your water source options in advance of purchase or building. It is very important that you have the water tested to ensure water quality is good for the intended crops. Make sure the location has good access to roads and markets. If your greenhouse will be a retail outlet, accessibility for customers is very important. If wholesale production is planned, trucks need to have easy access to the facility from major roadways. Orientation An Important Consideration Greenhouse orientation is important in most areas because it affects factors such as direct beam light transmission, light distribution, ventilation effectiveness, rain entry through vents, and vent effectiveness. Orientation is generally more critical for gutter-connected structures than for Quonset houses that are fan ventilated. Also, orientation for effective natural ventilation should have a higher priority than orientation for maximum light or light uniformity. Achieving light uniformity is generally more important than achieving maximum light. For a Quonset or tunnel greenhouse, an east-west orientation offers a slight advantage for obtaining more light, but a northsouth orientation can do equally well in the Latitude of the mid-atlantic region. Structural members cast shadows and must be taken into account. Orienting a gutter-connected unit is much more critical because you want to avoid the continuous shadows cast by the gutters. A north-south orientation is best for gutters because the gutter shadows move as the sun moves from east to west. Row crops are best planted in northsouth rows, which keeps sunlight distributed uniformly on both sides of the foliage. Building Permits You may need to obtain building permits, which can take up to 6 months to acquire. Check what the zoning requirements are for your location. Some structures may be considered temporary and will not require permits. Others will be considered permanent and subject to the Code. Check the building code requirements for your county. Find out if you need permits for such items as sewage systems, driveways, and building on or near wetlands; find out how to obtain the permits. You may need to meet ADA (disability access) requirements. Check with local government authorities before starting the project. 383

393 Facility or Business Layout Develop a business plan that covers the first 5 to 10 years of the operation. Plan a greenhouse range the greenhouse building, the head house, and any other support buildings to show both the current construction and the space to expand into at some future date. Depending on the type of business, plan such activities as the flow of incoming supplies, the flow of plants through the production process, and the flow of materials out to market; show the flow of these activities on a map of the site. If you will be operating a retail business, show the flow of people and parking. If the business will be wholesale, show the separate handling of incoming and outgoing materials. Design the flow of material through the greenhouse so that planting activities do not interfere with gathering orders for sales. Initially, you may want to plan a central head house or warehouse for seeding, transplanting, and repotting operations as well as shipping tasks. As the business grows, you can plan a separate facility for gathering orders and shipping. A goal of the business plan should be creating a facility that will enable the business to grow in an organized manner. Avoid getting boxed in so that one operation must cross paths with another. Look ahead to mechanization of operations. Allow space for expansion of supply storage. Glazing Double-glazing should generally be chosen over single-glazed sheets of plastic, fiberglass, or even glass, in order to reduce your heating requirement by 40 to 50 percent. Plastic films made for greenhouse use by reputable manufacturers are, by far, the most popular and time-tested plastic glazing in North America. The value of both UV inhibitors and infrared (IR) absorbers is well documented. Maximum light transmission is most important during the darkest days of winter. During the rest of the time, high light may be detrimental to production if ventilation is not adequate for removing the high heat load. While single sheets of glass have the highest transmission of light, at 92 to 93 percent, proper framing around the glass reduces the light level to about 70 percent. With crop wires, overhead pipes, and a little dirt, no more than 55 to 60 percent of outdoor light reaches the crop. You can achieve light levels of 55 to 60 percent at crop level by using double-cover polyethylene films or structured panels of acrylic and polycarbonate if your framing is well designed. Environmental Systems Heating, cooling, air circulation, and automatic control systems are important. These topics are covered in Chapter 23. Automation and Computer Control Personal computers are widely available and offer much more than just the ability to control the environment. Computers also enable you to keep records of the environment used to produce a crop and much more. It is important to be able to sense and control temperature within 1 degree Fahrenheit and to have a controller that can make changes as appropriate for maximum crop growth. 384

394 Chapter 23 Greenhouse Growing Environment: Temperature and Humidity David S. Ross, Professor and Extension Agricultural Engineer Introduction A uniform and controlled environment is essential for maximum crop production. Under certain conditions, the environment can also be ideal for insects and diseases. The goal of a good growing environment is to provide the ideal conditions for the crop, while avoiding conditions that are particularly favorable to insect and disease growth. Energy efficiency is also important for maximizing plant growth at the lowest cost. A plant s environment in a greenhouse comprises many parameters. Temperature, humidity, light, air movement, and carbon dioxide concentration are among the more important parameters (Albright, 1999). This chapter discusses temperature and, to a limited extent, humidity control. Although growers are able to reduce humidity in cold weather by ventilating and can wet floors to raise humidity, most growers do not control humidity. Fuels Natural gas, propane, and fuel oil are commonly used fuels for heating greenhouses. In some areas, hardwood chips or sawdust are readily available for combustion. A few landfills and methane generators produce methane that is used for the cogeneration of heating energy and electricity. Some operations may burn used oil, yellow grease (fat) or other alternative fuels. The choice of fuel is largely based on local availability, price structure, and burner cost. Compare the cost per 1 million BTUs of each fuel. Consider the combustion efficiency of the heating equipment and its compatibility with the heat distribution system that will be used. Heating Heating the greenhouse uniformly is critical for even plant growth. Regardless of the type of heating system used, the heat energy must be distributed throughout the greenhouse, particularly around the foliage of the crop. During the heating season, the proper operation of the heating equipment and the continuous air circulation equipment is important for growth management. Heating Methods Several different methods deliver heat energy to the plants. Forced hot air produced by small unit heaters or by large furnaces is a popular way of distributing heat in small individual houses and in many gutterconnected ranges. Larger operations use a central boiler system that utilizes two or three small- to mediumsized boilers to provide hot water or steam in stages as required for maintaining the temperature. Pipes placed along the perimeter or under gutters carry the steam or hot water to heat greenhouse air. A third method places the heating in the root zone through hot water tubing or pipes. A fourth method of heating uses propane gas fired infrared burners; heat from the burning gas is radiated down onto the foliage of the crop. The initial heating occurs at the top foliage but the foliage and other objects warm the air indirectly. Infrared heating may leave the air around the containers and root zone cooler than other methods that use air to carry the heat. Consider the crop when you select a heating system. 385

395 Closed and pressurized or separated combustion furnaces (80 85 percent or more efficient) are becoming more popular for new and replacement applications. Closed combustion uses outside air piped in for combustion and a blower removes the cooler exhaust gases out a separate pipe. More heat is extracted from the combustion gases via better heat exchangers, and the air (oxygen) for combustion comes from outside, not from inside the greenhouse. Warm, moist, pesticide-laden greenhouse air does not pass through the combustion side of the furnace s heat exchanger. The heat exchanger is less likely to rust out; leaking heat exchangers are responsible for combustion gases entering the greenhouse and causing crop damage. Furnace Efficiency Check the efficiency of the furnace before purchasing it. A furnace may be 80 percent efficient, which means that 80 percent of the heat energy goes to heat the greenhouse and 20 percent is lost out the flue, carrying the combustion gases away. The hot combustion air causes the draft that moves the combustion gas up the chimney. Closed-combustion furnaces use fans to move the air and thus do not require a large temperature difference. Efficiencies of percent are available. Avoid Air Pollution from Heaters Vented and Unvented Do not use unvented heaters because the combustion gases may contain enough impurities from the fuel to cause the formation of toxic combustion products. Some crops, such as tomatoes, are very sensitive to products of combustion. The damage on the plant foliage may lead one to believe insects, diseases, or pesticides are responsible. Symptoms on tomato are curling, twisting, white spots (SO 2 ), and stunting of new growth. Existing heaters may be causing crop damage from combustion gases leaking into the greenhouse. Today s tighter plastic houses require an outside source for makeup air to feed the combustion process. On a cold winter night when the heater is running continuously, the oxygen can be depleted in the greenhouse in 2 or 3 hours. Provide fresh air to the heater through a pipe about the same size as the flue pipe. Run the pipe from outside the greenhouse wall to near the combustion chamber. Outside, an elbow turned downward with screening on the end of the pipe outside will keep out rain and animals. For the regular common heating system, a good upward draft in the exhaust flue is required to pull air in for combustion and to move fumes out of the house. Air currents flowing over a greenhouse roof affect the functioning of the flue pipe. The chimney (flue) height must extend 3 feet above the ridgeline for a flue pipe at the ridge. Flue pipes exiting from any other locations must be 2 feet above a 10-foot horizontal line drawn to any part of the roof structure from the flue location. The flue pipe must initially be high enough to allow a 10-foot horizontal line to reach to the roof from the top of the flue, to that you will then add on 2 feet. This gives adequate clearance above the roof for positive draft without the pipe needing to be above the ridgeline. A cap on the chimney will help to reduce downdrafts, a common cause of fumes inside the greenhouse. All sections of the stovepipe must be tight to prevent leaks. Leaks of raw fuel can affect plants. Tomato plants are good indicators of sulfur dioxide and ethylene, two combustion gases that harm plants. Leaks in the heat exchanger may be the source of air pollutants. Using a bright light inserted into the inside of the heat exchanger, inspect heat exchangers for rust and holes. Look inside for rust and look around the outside for holes through which light can pass. Some dismantling may be required to do the inspection. Sizing the Heating System Physical factors affect the size of the heating system. These include the surface area of the greenhouse through which heat is lost, the temperature differential between the desired inside air temperature and the lowest outdoor air temperature, and the heat loss coefficient or rate of heat loss through the outside wall and cover materials. An inside nighttime temperature difference of 60 F is usually used for the temperature 386

396 differential. The heat loss coefficient expresses the heat flow in BTUs per square foot-hour- F. When multiplied together for the coldest situation, the result is the number of BTUs per hour of energy needed to maintain the desired temperature. This is the output heat requirement for a furnace for that house. Heat moves throughout the greenhouse by conduction, convection, and radiation (Fig. 23.1). To summarize, the basic equation for conductive heat transfer (output size of furnace) is surface area (square feet) times temperature differential (degrees Fahrenheit) times heat loss coefficient (BTU per square foothour- F). The result of this equation is the BTU/hour of output heat required from the furnace for the coldest night. Solar radiation Infrared radiation Air infiltration Conduction Figure 23.1 Greenhouse Heating Modes of heat exchange between a greenhouse and its surroundings. Example: For a 30-foot by 96-foot Quonset greenhouse with a ridge height of 13 feet, the outside surface area is roughly 4,300 square feet. The greenhouse is covered with a double layer of film plastic. The endwalls can be double film plastic or twin-wall polycarbonate or acrylic sheet. The heat loss coefficient, U, equals The temperature differential is 60 F (70 F inside, 10 F outside). These are the components for the conductive heat transfer equation, Q. A tight house is assumed so an air infiltration component will be included by slightly over-sizing the heating system. The heat loss for this greenhouse is Q = 4,300 square feet times 60 F times 0.70 = 180,600 BTUs per hour. This is the heat output required from the heater. At 80-percent efficiency, the heater or furnace will have a fuel input of 225,750 BTUs per hour (180, ). To allow for some infiltration air exchange, select a total heater capacity of 250,000 BTUs per hour. Rather than having one large unit, two smaller units are desirable, which enables one heater to still provide partial heat should one of the two heaters fail. Two heaters, each rated at 125,000 BTUs per hour, are fine. At 80 percent efficiency, each puts out 100,000 BTUs per hour. Energy Conservation Energy can be conserved by using an air-inflated double polyethylene cover or by using one of the doublelayer rigid materials available, such as double-layer acrylic and polycarbonate rigid covers. The heat loss coefficient reduces from U = 1.2 for a single-layer cover to U = 0.70 or less. This heat loss coefficient term alone makes a major change in the heat loss. Reducing air infiltration and the loss of heated air will lower costs. 387

397 Continuous Air Circulation Continuous movement of the air around the greenhouse during the heating season helps to mix the air and maintain a uniform temperature. Under stagnant conditions the air stratifies, with warm air rising and cool air settling to the bottom where the plants are located. Fans will break up this stratification. Air circulation helps to eliminate cold air pockets where moisture might condense. Carbon dioxide is delivered to the foliage if the air velocity is great enough to wash the surface air film away. If the air is dry, the free moisture on the leaf is carried away, reducing the threat of disease development. Air circulation is an important IPM tool for reducing environmentally induced problem areas where disease could develop. Keep air circulating continuously during the heating season. When ventilation becomes the dominant activity in warm weather, the air circulation system can be turned off for the warm season. The frequent air exchange by ventilation dominates the air movement in the house. Two methods of air circulation are in use the fan jet system and the horizontal airflow fan (HAF) system Fan Jet System The older system, the fan jet uses a pressurizing fan to push air down a plastic tube with holes along its length. The fans and the holes are sized to distribute air uniformly along the length of the house. The air returns back to the end of the house along the floor. This system has been replaced by the horizontal airflow (HAF) fan system because the fan jet uses more energy and requires the perforated tube to be replaced. The older system is recommended for long, narrow houses of less than 20 feet wide. Horizontal Airflow (HAF) Fan System The horizontal airflow fan system is recommended for low-energy, efficient air distribution. Small, lowhorsepower circulating fans create and maintain a slow circular airflow in the house, providing uniform temperature and good air circulation around the plants. The recommended total fan capacity is between 2 and 3 cfm (cubic feet per minute) per square foot of floor area. The larger amount is used in houses with hanging baskets or other restrictions to air movement. In a typical 30-foot by 96-foot house the airflow capacity is between 5,760 cfm and 8,640 cfm. Four HAF fans, each with a capacity of 1,500 to 2,000 cfm will do the job in this size house. HAF fans are installed 10 to 20 feet from the ends of an individual house in diagonally opposite corners. Two additional fans are installed 40 to 50 feet in front of the first fan to continue the push on the air mass. In gutter-connected houses two or three adjacent bays may be paired together so the air goes in one direction in them and then reverses direction in adjacent bays. The goal is to reduce the number of interfaces between opposing airflows. The basic idea is to get the air mass moving and to keep it moving (Fig. 23.2a and 23.2b.) Ventilation and Cooling Greenhouse ventilation may be required year-round to maintain the desired temperature, provide carbon dioxide for crop production, and remove excess moisture. Ventilation systems are very important in greenhouse management and may not be given enough attention by some growers. There are different ventilation requirements for each season and the choice of fans and a control system determine the grower s ability to maintain desired environmental conditions year-round. Natural and mechanical ventilation are two types of greenhouse ventilation systems. Natural ventilation depends on differences in temperature and wind pressures to move air in and out of the house. Mechanical ventilation is air movement driven by fans pulling air through the house from inlets on the opposite side of the greenhouse. Heat may be reduced by using shading to block the solar radiation from the house. Shading reduces both the heat load and the light received by plants. Evaporative cooling using a fan and pad system and natural transpiration through plants are two more ways of reducing heat. 388

398 Motorized inlet louver Exhaust fan Figure 23.2a HAF Fans Two HAF fans for horizontal circulation in greenhouses up to 60 feet long. Motorized inlet louver Exhaust fan Figure 23.2b HAF Fans Two additional HAF fans are added in greenhouses more than 60 feet long. Shading Shading is an important issue in ventilation and house cooling. Shading can reduce the heat gain in the structure and reduce the amount of ventilation required. Reduce the light to a level that is compatible with the crop; this shade will help to reduce the temperature rise. Place shade fabric over the exterior of the house or apply latex shade paint to the outside. Install moveable shade curtains inside the greenhouse and open and close as needed. Natural Ventilation Natural ventilation occurs when temperature differences or favorable wind conditions are present to cause adequate air movement. During cool weather the warm greenhouse air will rise and go out the roof vent while cool air enters the side vents to replace the warm air. The large temperature differentials drive the air movement. In the summer, temperature differentials are not as large; because the outside air is quite warm initially, air movement is not as great. Wind direction and aerodynamic factors make a difference between acceptable and unacceptable systems. Select your site carefully and orient the greenhouse to gain maximum benefit. 389

399 Roof vents Side vent Side vent Figure 23.3 Natural Greenhouse Ventiliation Natural ventiliation using ridge and sidewall vents, motorized for automatic control. To achieve air movement, natural ventilation systems use side and ridge vents, automatic or roll-up sides, or just ridge vents. Costs for natural ventilation may be lower than for mechanical ventilation, but success depends largely on nature and greenhouse orientation; also, with natural ventilation temperature control is limited. Some newer styles of houses are designed with roofs that open to any structural barriers that trap heat energy inside. Older ridge vent and sidewall vent systems should be staged with the ridge vent initially opening in increments (variable vent opener) during cold weather which allows warm air to escape and cool air to enter. If this is not adequate, then the sidewall vents should open in stages to allow cool air to enter while warm air escapes through the roof vent. Two to four stages of vent opening are desirable (Fig ). The new open-roof greenhouses utilize natural ventilation and have the advantage of the roof opening completely; the result is little restriction of air exchange and little structural shading of the crop. Mechanical Ventilation Mechanical ventilation uses exhaust fans and inlet louvers of specific sizes to achieve the correct ventilation rates. This system can be automated using thermostats, controllers, and computers. The negative aspects include higher initial costs and higher operating costs. The positive aspect is that you can increase your control over the operation. Ventilation systems used year-round are designed to provide at least one greenhouse volume air change per minute. This means the ventilation system changes the entire volume of air in the greenhouse each minute or more frequently. Calculate the volume by multiplying the floor area in square feet by the average height of the structure. Ventilation guidelines (of the American Society of Agricultural and Biological Engineering (ASABE)) vary from 8 to 12 cfm per square foot of floor area, in which 8 to 12 relates to the average height (in feet) of the building. Factors such as semi-permanent shading, thermal blankets for shading, and no use of the house in hot weather must be taken into account. Houses not used in hot weather may be adequately ventilated in cooler weather with a three-quarter volume change of air per minute. Some argue 390

400 that hot weather and higher inside temperatures can come in early spring, which upsets production schedules for those not prepared to move enough air. Summer ventilation requires the maximum air movement to avoid excessive heating of the greenhouse. Changing the air once a minute (one air volume per minute) keeps the air exiting the greenhouse to within 8 to 10 F of the air entering the greenhouse. Ventilate small greenhouses (air volume less than 5,000 cubic feet) at a rate of 1.5 air changes per minute for summer use (Fig ) Winter ventilation is needed on bright, sunny days to reduce the temperature and humidity of the air and to exchange air for replenishing the carbon dioxide. As the outside air is much cooler than the inside air, a slow rate of air exchange allows the incoming air to mix into the greenhouse air, achieving the desired result, without losing a lot of heat energy. The objective is to have an exchange rate of 20 to 30 percent of the air volume. In smaller greenhouses two-stage fans will allow several levels of ventilation. Motorized inlet louvers Exhaust fans Figure 23.4 Mechanical Greenhouse Ventilation Mechanical ventilation uses exhaust fans and motorized inlet louvers to change the air about once a minute remove solar heat gain in summer. Staging Mechanical Ventilation Staging ventilation is critical for good management. A minimum of two stages is desirable. A stage is the percentage of the total fan capacity being used at one time. A two-speed fan has a low speed capacity of about 70 percent of high speed. Staging scenarios are shown in the following options using two or three fans: Option 1. Two single-speed fans Stage 1 50% fan capacity (one fan) Stage 2 100% fan capacity (two fans) Option 2. One single-speed fan and one two-speed fan Stage 1 35% fan capacity (two-speed fan on low speed) Stage 2 50% fan capacity (two-speed fan on high speed) Stage 3 100% fan capacity (both fans on full speed) 391

401 Option 3. Small fan near peak of house; two single-speed fans Stage 1 20% fan capacity (small fan near peak of house) Stage 2 40% fan capacity (one large single-speed fan) Stage 3 80% fan capacity (two large single-speed fans) Stage 4 100% fan capacity (all fans running) Four stages of ventilation add a little cost to the system but allow more flexibility and better control. Note in Option 1 above: any winter ventilation will cause a large air exchange because at least 50 percent of the available capacity must be used. Cold air will enter quickly and the house will cool quickly from one end to the other until the thermostat senses the cooling and turns off the fan. Thermostat placement and HAF fan operation are critical to managing this scenario. Option 2 includes one two-speed fan, which on low speed provides about 70 percent of the fan s full speed capacity. Cold air enters the greenhouse more slowly than in Option 1 and has time to mix with the inside air; heated air is not drawn out of the house as quickly. Stage 2 has the same fan on high speed and Stage 3 has the addition of the second fan. This is an improvement because Stage 1 has a lower air-flow rate. Option 3 places a small exhaust fan and louver in the peak of the house to remove a small amount of warm air during winter ventilation. The slowly entering cold air has time to mix with the inside air. The temperature change of the inside air occurs more slowly than in the other two options. Moist or hot air can be removed without rapid disruption of the indoor environment. The larger two fans then come on in Stages 2 and 3 to pull air across the house uniformly. In Stage 4 the small fan comes on again to provide 100 percent capacity. Ventilation must respond to changing temperatures inside the house as the cloud cover changes. Moisture control requires that cold air be brought into the house and warmed up so it can hold more water. It may be raining outside but the cool air is actually drier than the warm inside air. Air moisture-holding capacity increases greatly as the outside air is heated and water is absorbed for venting to the outside. Multiple staging keeps temperature and moisture control manageable. Inlet Louvers The location and size of inlet louvers is also important for achieving success. During cold weather the air entering the greenhouse is cooler and heavier than the inside air and will settle to the floor. Size inlets to provide an air velocity of 700 feet per minute (fpm), which is 1.4 square feet per each 1,000 cfm of fan capacity. The required inlet area (square feet) can be calculated by dividing the ventilation fan capacity (cfm) by 700. At 700 fpm the outside air flows into the house to mix properly with the warm air. Evaporative Cooling Regular ventilation uses outdoor air at ambient temperature. On a hot day the air entering the greenhouse from outside may already be warmer than the desired inside temperature. By the time the air exits the house it is very warm. Two options for providing cooler air use evaporative cooling. Evaporation of water reduces the temperature of incoming air by up to 20 F on a day with low humidity. However, you need to consider the local relative humidity over the season to learn the benefit or lack of benefit of evaporative cooling. In Maryland, the benefit of evaporative cooling is low on humid days when the air temperatures are highest. You can use high-pressure nozzles to fog the house, particularly near the inlet louvers, to provide moisture for evaporation. Evaporative cooling occurs when the water in the fog takes heat out of the air to warm itself and convert it into water vapor (gas). (Water takes 1,100 BTUs out of the air to evaporate 1 pound of water that is at 80 F.) Removing the heat from the air causes the cooling. The moisture added to the air raises the humidity of the air. The solar heat load on the house reheats the air as it moves the length of the greenhouse. Continuous air exchange generated by exhaust fans removes the warm, moist air and pulls more air through 392

402 the house to keep the process going. Unless the relative humidity is high, several degrees Fahrenheit of cooling can be achieved. Evaporative cooling pads are sized to the maximum fan airflow to minimize the restriction to airflow. Water trickles down onto the top of the pad and moves down through the pad material to wet the entire surface. The evaporative cooling occurs at the surface of the pad. The exhaust fan pulls the air through the house. Plants are evaporative coolers. A full greenhouse of large plants creates an excellent evaporative cooling system as the plants transpire through the leaves. A combination of variable shade along with transpiration from highly productive plants can be a very effective cooling system. Winter Moisture Control One use of ventilation is to dry the house in the evening to reduce the free moisture that may condense on the foliage overnight as the plant surfaces cool. Moisture that forms on foliage supports disease development. Botrytis is an ever-present disease in the greenhouse. A cool greenhouse (55 65 F) at 98 percent humidity for 8 hours and relative humidities above 80 percent in the late afternoon are cause for concern. Relative humidity is measured using both a wet bulb thermometer and a dry bulb thermometer. A psychrometric chart allows you to read the relative humidity quickly and easily. This instrument (psychrometer), which is not expensive, is a tool most greenhouse operators find useful. For a few more dollars, models with fans blow air over the wetted wick of the wet bulb thermometer. The wet bulb temperature is the temperature of the air after evaporative cooling has reached equilibrium. Air must pass over the wick faster than 9 feet per second from a fan or by using a sling psychrometer whirled by hand to create the evaporation. In a house with dense foliage or when crop watering occurs late in the day, drying the house in the evening may be necessary for removing free water. Water may be caused by plant transpiration or plant watering. This drying process reduces excessive condensation on the inside cover of the greenhouse. When the air cools down to the nighttime setting, the wet bulb temperature goes up along with the relative humidity. The dew point is the temperature at which moisture starts to condense out of the air (100 percent humidity); at the dew point the wet bulb temperature and the dry bulb temperature are the same. Motorized inlet louver Figure 23.5a Winter Moisture Control Cool air is mixed into warm air by HAF fans while warm, moist air is removed by a low flow rate exhaust fan. 393

403 Exhaust fan HAF fans Motorized inlet louver HAF fans Furnace unit Heat Figure 23.5b Greenhouse Air Exchange After air exchange, cool air is heated to increase its moisture-holding capacity. Follow these steps to perform the drying process: First, vent the house to remove at least part of the house s volume of moist air (Fig. 23.5a.). A small exhaust fan works best and removes the air in a few minutes. Then, turn on the heating system to warm up the cold air that has replaced the air you removed (Fig. 23.5b). At no time should the incoming air lower the house temperature too much. HAF fans are great for mixing the air to maintain adequate and uniform temperatures. After a few minutes of circulating this heated air around the greenhouse and through the foliage, vent some of this air from the house. The fresh air entering the house will be warmed and drier than the air you removed. Sensors and Controllers Capillary coil thermostats have been used for many years as simple control devices for both heating and cooling equipment. Low-cost thermostats have a differential of 3 to 5 F from the set point. This means the thermostat set for 70 F (5 F differential) may respond anywhere between 65 to 75 degrees. Because this wide range does not offer good control, you must set a second thermostat at a temperature outside this range to avoid a conflict between heating and cooling. Two thermostats (set at 65 F and 70 F) with a differential of 3 to 5 degrees could actually function on the same temperature, causing both the heating and cooling equipment to operate at the same time. Figure 23.6 Control Sensors Aspirated insulated box with control sensors. 394

404 There is no reason to use the inaccurate sensors. An electronic thermostat with a small differential of plus or minus 1 F costs a little more, but it provides the necessary precision and control to maintain accurate temperatures. The savings in energy cost alone may pay the cost difference in a short time. Several thermostats are needed to handle the multiple stages of heating and ventilation. Coordinating all the settings is a challenge, particularly if all the thermostats are not in the same location. Aspirated sensors are important for accurate temperature measurement. Place thermostats in a box through which a small fan draws greenhouse air. The box blocks the sensors from direct exposure to heating by the sun. The airflow helps to ensure that the sensors are exposed to the same greenhouse air temperatures (Fig ). More accurate control is available using microprocessor-based controllers, which handle specific segments of the environment. Thermistor and thermocouple temperature sensors are used for faster and more accurate temperature measurements in aspirated boxes. A solid-state integrated circuit monitors environmental data in the greenhouse and creates output signals. These signals activate equipment based on a set of internally programmed instructions. The microprocessor, a simple, low-cost device that is reliable and accurate, works well in the greenhouse environment. Greenhouse controllers are available in many sizes and have advantages over older equipment. All components are located in one waterproof enclosure, which lessens moisture and dust problems and reduces maintenance. Installation time is decreased because all relays, switches, and controls are prewired. Sensors are remote and can be mounted several hundred feet away from the control box. Fuel usage is reduced because of more accurate sensing and control. The simplest controller, such as the Wadsworth Step 50A, is designed to provide heating and ventilation integration for one greenhouse or zone. It has three cooling stages, a set point, and two heating stages. The differential temperature between stages is adjustable, and the unit has day and night temperature settings. A night lockout will disable one or more cooling stages. An adjustable time delay between stages prevents rapid cycling of equipment. For a single house, most manufacturers have a basic controller like this one. Increased capability, mainly in greater number of stages, is available in other controllers, including the Wadsworth Step 500; the Growmate Series from Greenhouse Systems, Inc.; the Davis Engineering DIFtrol 24A; and Acme-Groton II from ACME Manufacturing. The next step up from the basic controller are units that control temperature and other environmental factors and equipment, such as irrigation systems and shade/heat retention curtains. Most of these controls are connected to a computer for central programming and system reporting. Controllers come with switching relays wired for each stage. The relays can be connected directly to low-power equipment, such as motorized shutters, vent operators, and steam or solenoid valves. Equipment with motors that draw large amounts of power when starting require motor starters or contactors that are activated by the relay. The starter prevents electric arcing that would destroy the relay. Some manufacturers can supply prewired boxes with power relays. These simplify installation. There are a number of features to look for in good controllers: override switches for providing manual control, accuracy of from half a degree to 1 F, fixed or differential temperature steps between stages, daynight settings, time delay between stages, temperature display, indicator lights to show which equipment is on and which stage is activated, programmable night cooling lockout, aspirated sensor box, and vent control. Controllers range in price from $600 to $1,400. This compares to $50 each for five or more thermostats that might be necessary. Motor starters are $40 to $80, depending on size. Better control of the greenhouse environment means higher-quality plants at less cost. Controllers are designed to give the precision control that ordinary thermostats cannot provide. 395

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406 Chapter 24 Greenhouse Systems Maintenance Chuck Schuster, Extension Educator, University of Maryland Heating System Maintenance The heating system is a very important part of a greenhouse system. Proper maintenance can help prevent many of the common problems that may arise when we are busy doing other work. Prepare and maintain the heating system for use before it is needed. Consider your fuel type, typically propane or fuel oil, and in some cases products including yellow grease. Fuel oil systems are used in many different settings. Fuel oil can be used in overhead mounted burners to heat water in a boiler as an example. It is important to prepare the fuel oil systems by replacing the filter on each unit at least annually. Quality of fuel can be evaluated when looking at the filter. If sludge is found in the filter bowl, check the height of the draw line coming from the oil tank. It should not remove oil from the extreme bottom of the tank. Water will settle in the bottom helping to form this sludge. Fuel additives can help remove this water from the tank and burn it through the system. Protecting the tank from temperature extremes can also be very useful. On the heating unit itself, locate and remove the spray nozzle. In some cases a good cleaning can add life to the nozzle. If it appears the spray pattern is not even, replace the nozzle. It is helpful to keep a spare of the proper flow rate and angle in the supply cabinet, this will prevent long outages if something should occur during the peak need period. Adjust the igniter electrodes to the manufactures specifications. This is different for different burners. Propane systems require an annual check on the condition of regulators. Regulators can freeze during extremely cold weather. One propane source indicates it is useful to protect from moisture with a cover. As with oil burners, check the burn pattern and efficiency during operation. Many heating units are located in individual greenhouses. This potentially leads to media and rust buildup in the heat exchanger. Remove covers, cleaning the heat exchangers, removing as much foreign material as possible, this will increase efficiency. Use caution not to damage the exchangers, do not attempt to scrape rust free, use a brush or low pressure compressed air. Vacuum out as much debris as possible. The chimney removes exhaust gases from the heater to the outside. No matter what the fuel source, evaluate the condition of the chimney, and repair or replace as needed. Check chimney caps to determine that no debris has gotten in the chimney to prevent free flow of the exhaust gases. Worn, damaged or extremely rusty chimney pipes should be replaced. Failure of the chimney can lead to a carbon monoxide buildup which can be harmful for the workers and plants in the greenhouse. A CO detector may be a useful addition to the tool kit when plant growth seems to be lagging behind what is expected. The thermostat is often the most overlooked part of the heating and ventilation system. These should be protected from direct sunlight, and from irrigation water. Do not place them where they will be improperly influenced by opening and closing of ventilation shutters, near doors, or other opening that allow outside air to enter. Thermostats should be checked using a Maximum and Minimum Thermometer. Watching the high and low temperatures in a structure and comparing them to the settings on the thermostat can help determine if the thermostat is malfunctioning. 397

407 Ventilation Fans Maintenance Ventilation fans move air to prevent excess temperature buildup and potential disease issues. Turn power off to the unit before doing any service. Check each unit to determine condition of the drive belt and replace as necessary. Clean fan blades to remove any rust or dirt buildup, this will help preserve the bearings by keeping the blades balanced. Tubes should be evaluated when the greenhouse is nearly empty for ease of replacement. Check suspension supports because the more these plastic ventilation tubes are used, the more they will fatigue and tear. The inlet and exhaust louvers should be inspected to ensure proper closure when the fan is not operating. Louvers that do not close fully will allow heated air to escape and waste fuel. Inlet louvers are thermostatically controlled. These thermostats should be evaluated to determine open and closing temperatures and may need to be adjusted for different crops. Thermostats should also be protected from direct sunlight, irrigation moisture and not placed near vent opening or doors. Overhead Ventilation Maintenance Some greenhouses use overhead ventilation systems. These systems reduce fan noise and energy costs. Overhead ventilation can be manually controlled or by a thermostat. Check seals on this system when in the closed position. Review placement of thermostats as above. Irrigation Systems Maintenance A review of all irrigation system components is important. Each emitter should be tested for proper flow rate and pattern. Filters should be removed and cleaned, replacing filters as necessary or recommended by the manufacturer. Debris is not the only concern with filters and emitters, minerals in water may cause clogged filters, emitter pattern distortion and poor flat or pot coverage. This build-up can clog filters, effect emitters, and be problematic for fertilizer injectors. Visual evaluation is important. While crushed lines may not leak, flow rate is reduced which may impact flow at emitters or nozzles. Water lines should be tested, repaired and replaced as necessary. Review and the pressure regulator making adjustments to meet the needs of all of the emitters. Place a pressure gage on the end of the line to do a proper test. Controls should be tested and adjusted to maintain proper moisture levels. Mist bench controls should be tested and adjusted as needed. Fertilizer Injectors Maintenance Fertilizer injectors should be serviced as recommended in the owner s manual. Salts from soluble fertilizer can cause wear to moving parts as can minerals from the fresh water supply. Disassemble and carefully clean the injector. Reassemble using non silicon lubricants. The stock tank should be emptied and settled material clean out. Suction strainer should be cleaned and checked to determine if the screen is still intact. This prevents fertilizer that did not dissolve from being drawn into the injector and causing possible wear to the injector or clogging of the emitter. Calibration should be done at this time. After determining the ratio the operating injector ratio, check the output with actual fertilizer solution using an Electrical Conductivity (EC) meter. Adjust the injector ratio or change the fertilizer solution to correct it to the desired EC. Computer Controls Many greenhouses utilize computers to control various functions including ventilation fans, heat, louvers, mist benches and irrigation systems. These computers are often not located in the office or clean areas and risk being damaged by moisture or foreign debris which can decrease cooling or cause electrical problems. Check computer storage cabinet inlets and clean any restrictions so cooling air may enter. Inspect power connections, back-up batteries, and all input connections. Check the routes of all sensor wires for damage and proper shielding. If a phone backup is part of the system, check phone numbers and proper operation. 398

408 Glazing/ Covering Energy loss through damaged glazing is important to review. Replace all damaged glazing as necessary. Check end walls for air leaks, repairing as needed. Carts can damage doors and seals, repair as needed. Check seals on doors for a tight fit. Evaluate light transmission through glazing. Glazing or coverings that are dirty or poor quality can negatively affect plant growth and quality. When performing light transmission evaluation review the following. UV Visible Light Infrared Light Red Light Spectrum Blue Light Spectrum If transmission rate is below recommended standards consider options to improve light availability. To keep summer temperatures under control and reduce potential excess energy use, shade cloth can be installed. These can be applied to the outside of the structure, secured to the frame near the ground to prevent wind damage or installed inside the structure often on a motorized system. The shade cloth must be evaluated for overall condition, and replaced if necessary. Proper use of shade cloth will decrease energy usage from excess ventilation fan operation. Benches Clean and repair all benches before trying to fill the greenhouse. Remove asbestos benches where applicable. Remove damaged wood and replace with appropriate materials. Determine weight of plant material and moist media when considering sizing of supports for benches. Overhead Plant Systems Many greenhouses utilize over basket systems. Test motors and irrigation systems to these units prior to putting plants below or on the rack. Grease bearings where applicable, check motor to drive system belts, chains or gearboxes as outlined by the manufacturer. 399

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410 Chapter 25 Greenhouse Substrates Andrew Ristvey, Extension Educator Introduction This chapter will discuss the physical and chemical properties of soilless substrates or potting soils and will provide in-house tests to examine these properties for developing management strategies for better plant growth. Other terms for soilless substrates are organic substrates, media, or medium. Substrate Basics There are several important aspects of choosing a substrate for a nursery or greenhouse. Substrates, fertilizers, and irrigation water quality and quantity, are linked together and each has an effect on the other and on plant growth (Fig. 25.1). The way a substrate holds air, water and nutrients is vital to the health of the roots and consequently the growth if the plant. Changing one will affect the others. Choice of substrate will have an effect on fertility and irrigation management. The information here will help a grower understand substrates and develop management programs to suit the nursery or greenhouse operation. Substrate Plant Irrigation Fertilizer Figure 25.1 Substrate, Irrigation and Fertilizer Triangle Each affects the other and the health of the plants. Substrate Components There are a variety of organic and inorganic substrate components presently utilized in the industry, and each of which has its own physical and chemical properties. These components can be used individually or mixed together to create substrates with different physical and chemical properties suited to the requirements of a particular crop. Below is a list of typical components commonly found in most soilless substrates. Peat moss: There are several types of peat. Sphagnum is the most widely utilized as a main component in commercial mixes, because of its stability and high water holding capacity. Sphagnum peat usually has a low ph and often is amended with lime. Pine bark: Pine bark is another popular component, used especially for increasing the pore size and aeration in a substrate. Pine bark is relatively stable because it is made of lignin, a material not easily degraded by microorganisms. There are different grades and sizes of pine bark that undergo various aging processes. One should inquire about these factors before buying. Ideally, aged or composted pine bark fines 401

411 of sizes no more than 3/8 inch are best. Bark should contain little to no cellulose (wood). Pine bark is known to reduce the effectiveness of plant growth regulators if applied as a drench. Coir: This is coconut fiber and has been studied extensively as an alternative to peat moss because of the environmental issues surrounding peat extraction. Coir has a high water holding capacity and is easier to rewet than peat. Depending on its source, coir may have very high chloride content. Consider lab analysis to determine chlorine contents before use. Perlite: Perlite is a commonly used substrate component often used as an amendment to increase the pore space in peat-based substrates. It is an inert volcanic silica that is expanded or puffed by exposure to high temperatures. Because of the internal pores within the perlite, it can actually hold water, however, most of that water is not available to plants. Perlite comes in different particle sizes from fine to course grade. Typically, medium and course grades are mixed with peat moss to make bedding- plant or propagation substrates. Vermiculite: Like perlite, vermiculite is a mineral extracted from mines and heat expanded. Vermiculite has desirable characteristics as an amendment for peat substrates as it optimally retains water and air. Rockwool: Fibrous material manufactured by liquefying basalt rock, steel mill slag or other minerals, and then spinning into fibers. It is very porous with a high water holding capacity with much of that water easily available to plants. Rockwool is good for hydroponic or subsurface irrigated crops. Use only the basalt rock-based material because it is the most inert and will not interact with nutrient solutions. Rockwool has a relatively high ph so fertility levels must be monitored. Since it is only useful for a few growing cycles, disposal can be a problem because of its bulky volume. Peanut Hulls: Peanut hulls are becoming a popular component in substrate mixes. Peanut hulls are approximately 37% lignin, and are slower to degrade than other materials with greater cellulose content. Rice Hulls: Rice hulls are also available for use as a substrate component. Rice hulls increase porosity when mixed with other components like pine bark or peat. However, some have experienced rice hulls settling and forming layers which restrict water infiltration throughout the substrate. Whole Tree: With the high demand for pine bark increasing and supplies dwindling, new substrates are being developed. Whole-tree is a substrate made from all parts of the tree, including the bark, wood and leaves. While research has shown that it can be safely used as a growing medium, it is primarily cellulose and may need up to 30% or more nitrogen to overcome nitrogen drawdown from microorganism competition. Other Common Substrate Components and Amendments Sand: Concrete grade sand is typically used to improve ballast (increase weight) to prevent blow-over when using light weight mixes like peat. However, the extra weight may also increase shipping costs and increase the workload on labor. Concrete grade sand is recommended because it has large particles and is washed of silt or clay particles. Therefore drainage can be increased if used. Smaller sand particles may help to increase water holding capacity. Lime: Comprising of mostly calcium carbonate (calcitic) or calcium magnesium carbonate (dolomitic), this material is used to buffer organic substrates and regulate ph. Dolomitic lime is most often used because it provides both calcium and magnesium. There are different grades of lime. Pulverized lime has small particles and is very reactive, quickly adjusting, buffering and raising ph in substrates, however it has little 402

412 longevity when incorporated. Pelletized lime is pulverized lime with a dissolvable coating. Its longevity is only slightly longer than pulverized lime. Granular lime has larger particle sizes than pulverized or pelletized lime, and therefore less reactive but with greater longevity. Granular lime can be mixed with pulverized lime to get the benefits of both quick reactivity and longevity for buffering. The addition of lime should be based on water quality, specifically, the alkalinity of the irrigation water. Gypsum: Used to add calcium and sulfur to substrates without increasing or decreasing ph. Typically found in most commercial substrates along with dolomitic lime. Other Nutrient Amendments Also, the addition of other nutrient amendments can be made, including granular micronutrient amendments. A variety of metal (nutrient) chelates, especially for iron, are used to improve nutrient availability. Chelates differ in form and effectiveness. The ph level can have an effect on the availability of the chelated nutrient. Iron sulfate was used in the past to manage the ph level. However, it can increase EC dramatically, and is short lived in organic substrates, quickly leaching out with irrigation water. One popular amendment called superphosphate is no longer recommended as an addition to soilless substrates. Superphosphate leaches from soilless substrates very quickly. Phosphorus is a pollutant in fresh water systems and is a very problematic nutrient. There are now better methods to apply phosphorus contained in low phosphorus soluble fertilizers and slow or controlled release fertilizers. Choosing a Substrate Based on physical and chemical properties, choose a substrate that fits the growing system. Most commercial substrates are developed for particular growing conditions and are labeled for specific uses. For the most part, commercial brands can be relied upon to give consistent substrate properties based on plant needs, however to be on the safe side, before planting, send a sample to a laboratory for analysis or at the very least, check ph and EC of each lot purchased. See monitoring methods in sections 3.2 and 6.0 below. Some substrates have preincorporated amendments that increase EC to over 2.5 ds/m, which can be initially high if irrigation is not immediately applied after planting. Physical Properties What are the key factors that determine how a substrate holds air and water? These properties are Air-Filled Porosity (AFP) and Water Holding Capacity (WHC). Air-Filled Porosity is the amount of air, by volume, that a substrate holds after irrigation and after drainage. Water Holding Capacity is the amount of water, by volume, that a substrate holds after irrigation and drainage. There are many factors that determine AFP and WHC in organic substrates, but specifically the direct factor is the porosity and pore size created by the components of the substrate. Pore size and the distribution of pores in soilless substrates influences AFP and WHC. While particle size plays a direct role in soils, there is less influence of particle size to AFP and WHC in soilless substrates. While it is true that large particles like pine bark create large pores, the bark itself also has internal pore space that holds water. However this water may not necessarily be available to plants. Of course, substrates with a lot of small particles will have a high WHC. So, to some extent, particle size does play a role in AFP and WHC, but it is the composition of the substrate itself that is the primary factor. Capillary forces are the attraction of water to surfaces strong enough to overcome gravitational forces. The smaller the pore space the stronger the capillary force, and the more water a substrate will hold, including internal pores within large particles. 403

413 Other Factors Affecting AFP and WHC of the Substrate Age: Substrate degrade as they age which increases the amount of small particles and decreases pore size. The aging process will typically increase WHC and decrease AFP. It is not recommended to reuse a substrate for successive growing cycles. This avoids the need to adjust irrigation management among pathogen problems carried on from the last use. Container Geometry: Given the same substrate, smaller and squatter containers will hold more water than larger taller containers on a percent volume basis. Handling: Poor handling habits of substrates can reduce the pore size of the substrate. Smaller pores will increase WHC and reduce AFP. For example, when placing plugs in pots, do not compress the substrate around the plug and do not stack trays or pots on top of each other. This compresses the substrate and reduces pore size and AFP. Allow irrigation water to naturally compress the substrate around the roots. Field Test for AFP and WHC An in-house field test can determine AFP and WHC of substrates in containers. This test uses water to determine the percent volume of AFP and WHC by taking weight measurements. This test can be done before plants are placed in containers or with a plant in the container to test how the substrate has changed over the growing cycle. The latter method is especially helpful if plants have been in a container for over one year. Note that one gram (a unit of mass) of water is equal to one cubic centimeter or one milliliter (a unit of volume) and mass can be converted to volume with the metric system. If a metric measuring device is not available, ounces can be converted to grams (One ounce equals twenty-eight grams). What is needed: 1) A typical growing container; 2) A scale that can measure at least 15 pounds or 7 kilograms or a beaker to measure water volume; and 3) A measuring device that utilizes the metric system of measurement Steps: 1. Find a common container, tape the holes and weigh it. Record the weight as W4. 2. Fill the container with water to the level of which it is typically filled with substrate and weigh it. Record the weight as W3. Alternatively, directly measure the volume to which the container is filled. 3. Fill the container with substrate to the level of the water in the first measurement. The substrate should not be completely dry, in fact, the next step will go quicker if the substrate is moist. Most organic substrates repel water when completely dry. 4. Slowly add water to the container, saturating the substrate and allowing the water to evacuate the air. Water should be visible at the top of the substrate. Weigh the container and record the weight as W1. 5. Remove the tape and allow the water to drain for an hour, letting the substrate come to container capacity. Weigh the container making sure to keep the container level. Tipping the container will allow more water to come out. Record the weight as W2. Alternatively, the water can be captured and be directly measured as the volume that came out of the container. 6. % AFP = (W1 W2) (W3 W4) x If the volumes have been recorded directly, the volume of water that came out of the container is the AFP. Calculate % AFP by dividing the volume that drained from the total volume of the container and multiplying by To test for WHC dry the same substrate in an oven for 48 hours at 180 F. Weigh the substrate and record as W5. 9. % WHC = (W2 (W5 +W4) W3) x 100. Remember to do the math inside the ( ) first, then subtract from W2, and then divide by W3. Multiply by

414 Recommendations For this field test, substrates growing annuals and plugs in small containers, it is recommended that AFP is around 15 to 20%. IF the AFP is any lower than that, then the roots should be monitored often. For containers greater than 1 pint and substrates with pine bark, AFP s should be between 20 and 35%. Some nurseries choose to have AFP s greater than 35% mainly when growing fine-rooted ericaceous species like azalea. These highly porous substrates hold very little water and leach quickly. In this case, the irrigation manager needs to water these plants often in short durations. The irrigation manager should manage irrigation carefully as these highly porous substrates are prone to leaching and nutrient loss. Chemical Properties Organic substrates are not inert, although they are not as chemically reactive as soils. Since soilless substrates are comprised mainly of organic components, they have more cation exchange capacity (CEC) and less anion exchange capacity. Cations are positively charged ions and include most of the micronutrients and many macronutrients. They include iron, magnesium, calcium, potassium etc.. The anions are negatively charged ions and they include nutrients like sulfur in the form of sulfate, phosphorus in the form of phosphate and nitrate. Anions are not held by organic substrates and are easily leached. The most important nutrients for management are both anions; nitrate and phosphate which is why an irrigation manager must know the water holding capacity of their substrate to prevent leaching. Another important factor that plays a role in nutrient availability is ph. Both CEC and ph affect nutrient availability. Substrate Cation Exchange Capacity Cation exchange capacity (CEC) is the ability of the soil or soilless substrate to exchange cations. Since many nutrients are cations, it is a direct relation to fertility. Buffering capacity is also associated with CEC as this helps substrates to resist sudden changes in ph. The more aged or humified (biologically aged organic matter) components in the substrate, the higher the CEC. Organic substrates, including those with sphagnum peat or aged pine bark typically have good CEC. Substrate ph Nutrient availability depends on ph in soils and in soilless substrates. ph is the amount of hydrogen ions (H+) in an aqueous solution (water) and ranges from 0 (most acidic) to 14 (most basic). The amount of hydrogen ions are exponentially and inversely related to the ph value. There are 10 times more hydrogen ions in a solution with a ph of 2 than in a solution with a ph of 3, a 100 times more than a solution of 4 and 1000 times more than a solution of 5. Since the hydrogen ion is positively charged, it interacts with nutrients, making them more or less available for uptake by plants depending on the ph level. For instance, low ph makes iron and manganese more available and high ph makes the same nutrients less available (Table 25.1). In soilless substrates it is recommended that the ph be between 5.5 and 6.2 for optimal nutrient availability, but the ph may need to be adjusted for a specific plant s needs (Fig. 25.2). Table 25.1 Effects of ph on Nutrient Availability in Soilless Substrates Nutrient Availability Soluble: available to plant roots Insoluble: not available to plant roots Highly soluble: toxic levels Very low ph (less than 5.0) Magnesium, calcium Manganese, iron, copper, zinc, boron Low ph ( ) Manganese, iron, copper, zinc, and boron Molybdenum, calcium, magnesium, sulfur Optimum ph ( ) Maximum availability of essential nutrients High ph (6.4+) Molybdenum, magnesium, calcium Phosphorus, iron, manganese, copper, zinc, boron 405

415 Species Crossandra Eustoma Astilbe Calendula Campanula Crocus Dianthus Exacum Freesia Hyacinth Narcissus Pentas ph Range I I I I I I I I I I I I I I I I I I I I I I I I I I I Celosia Dianthus Gernaium Marigold, Afr. Rununculus Amaryllis calceolaria Dracaena Easter Lily Ivy, English Oxalis Pepper, Orn. Sunflower African Violet Christmas cactus Hibisucus Kalanchoe Aster, Garden Begonia Caladium Clerodendrum Echinacea Primula Rose Chrysanthmum Hydrangea (Pink) Impatiens, NG General Crops Bougainvillea Poinsettia Gerbera Gloxinia Streptocarpus Pansy Petunia Salvia Snapdragon Vinca Cyclamen Orchids Hydrangea (blue) Azalea I I I I I I I I I I I I I I I I I I I I I I I I I I I Figure 25.2 Suggested Substrate ph ranges for specific greenhouse crops in soilless substrate. Source: Whipker, B.E., W. Fonteno, D. Baily, and T. Calvins. N.d. Recording, Interpreting, and Managing Substrate ph. In PourThru Nutritional Monitoring Manual. North Carolina State University. 406

416 Irrigation Water Quality: Effects on Substrates Water alkalinity is the amount of carbonates and bicarbonates dissolved in the irrigation water. The higher the alkalinity, the greater the buffering against change in ph as carbonates absorb hydrogen ions. However, a water supply can have too much alkalinity (above 150 ppm) which can eventually increase the ph in a substrate, leading to certain nutrient deficiencies like iron or manganese. The addition of an acid injection system can alleviate problems with alkalinity. Be sure to have the irrigation water tested to determine alkalinity. Check with an extension agent for help in determining what actions to take, whether it is acid injection or through amending a substrate with lime. Managing Substrate ph There are several biological and cultural reasons that cause ph to increase or decrease apart from irrigation water quality. Some plants like zonal geraniums, marigolds and tomato naturally acidify the substrate so they require slightly higher ph substrates than other species. Other species like petunias, pansies and vinca naturally increase substrate ph. Nitrogen fertility plays a large role in substrate ph. The use of nitrate increases the ph of substrates and the use of ammonium acidifies substrates. If there is a requirement for one of these in the fertility management, especially for the use of nitrate, it is recommended that consistent substrate monitoring be part of the management strategy. Amending Substrates and Adjusting ph Since ph plays an important role in nutrient availability, some modifications may need to be made to substrates if they are being mixed at the nursery. Preincorporating (mixing before potting) amendments to control ph, cation exchange capacity, or nutrition is commonplace for nurseries that have decided to make their own mixes. After planting there are methods for managing substrate ph including use of specific fertilizers. Lowering ph Organic substrates, especially sphagnum peat moss and pine bark are naturally acidic, so little needs to be done pre-planting to maintain low ph. Some amendments have been used in that past including elemental sulfur or iron sulfate. However, the most effective methods for keeping ph low are using acid fertilizers or acid injection (typically with 35% sulfuric acid). Remember that, sulfuric acid is a very strong acid which requires great care in handling. Recommendations for sulfuric acid injection are based on the water test and the meq/l of alkalinity shown on the test results. Eleven ounces of sulfuric acid (35%) per 1000 gallons of water are required mitigate each meq/l of alkalinity. This procedure may need to be adjusted depending on the irrigation water s ph. For a quick remedy, an iron sulfate drench at 1.5 lbs per 100 gallons can be used but this dramatically increases EC and can damage foliage if applied on leaves. Care must be taken and EC monitoring is essential. Increasing ph - Liming Substrates The main reason to add lime is to buffer the substrate from rapid changes in ph. There are two main types of lime, dolomitic with both magnesium and calcium carbonates and oxides. Calcitic lime only contains calcium carbonate and oxide. Dolomitic lime is usually recommended because it contains both calcium and magnesium in the correct proportions for plants. There are three types of liming materials. Pulverized lime is powdered lime. It has a quick affect but does not last long in the substrate. Pelletized lime is pulverized lime with a sticking agent that dissolved with water. Its longevity is only slightly longer than pulverized lime alone. Granular lime has larger particles so it lasts much longer than pulverized lime. It is recommended 407

417 that for crops that stay in the nursery for longer than 6 months, a mixture of pulverized and granular lime be incorporated. So is there a magic formula or rate of lime for all substrates? The answer is no. Actually, liming depends on something apart from the substrate. The most important factor the substrate manager must consider is water quality and water alkalinity. Liquid lime is most often used as a management tool for immediate increase ph in substrates that have become too acidic during the growing cycle. It is mixture of lime and water. It is typically used at a rate of between 1 and 4 quarts of lime to 100 gallons of water and applied directly to the surface of the substrate. The higher the concentration of lime, the more effectively it raises the substrate ph. Residues on plant tissue should be rinsed immediately after to prevent burn. Substrate ph should be monitored within 24 hours after use and consecutively throughout the week after application. After 24 hours, if the ph range is above 7.0, irrigate plants to leach and continue to monitor. Chemical Properties Monitoring Monitoring ph and Electrical Conductivity (EC) in the nursery or greenhouse is a vital management strategy for ensuring plant root health. Electrical conductivity is a measurement of soluble salts in the media and can give an indication of the nutrient load in a container. However measuring EC is a management tool for quickly detecting problems. It cannot give any specific information about which nutrients are in the substrate or their concentration. There are several methods for testing for ph and electrical conductivity including the Virginia Pour- Through, Saturated Media Extract (SME), or a ratio of substrate and water as in a 1:1.5 dilution. The pourthrough is the easiest and least disruptive but may incur the most error. The SME will be most consistent but will require samples of media from the root area of the plants. It is most important to choose one method and continuously use it. With each of these methods, distilled water should be used. If distilled water is not available then irrigation water will suffice, but the EC of that water should be subtracted from the final EC result. High alkalinity water will skew ph results. The two tests most commonly used are the Virginia Pour- Through and the SME, which are explained below. Some growers have hand held probes that can be stuck directly into the substrate, although the substrate must be moist for consistent results. Monitoring should be done on a frequent basis, but at least during times of low humidity and hot temperatures, as soon as amendments are incorporated into substrates, or even over winter when warm temperatures exist in the greenhouses or overwintering houses. Maryland Pour Through This method should be performed after an irrigation event when the containers are at or near saturation. Place a tray under the plant container to collect water. For a 6 inch diameter container, pour about 3 ounces (approx. 100 ml) of distilled water evenly over the top of the substrate, or enough to collect about 2 ounces (approx. 60 ml) of leached water. Measure the EC and ph of the sample. For containers 1 pint and larger, tip the container 45 degrees and collect a sample of water from the drain hole, instead of pouring water into the container. Be sure there is enough sample to cover the probes electrodes. This process should be repeated on as many containers and in different places as possible to access the population of containers and determine where plants need water or nutrients. Saturated Media Extract (SME) Collect substrate from individual containers or collect any subsamples and combine. For smaller containers such as plug trays, plants will need to be sacrificed in order to obtain substrate samples. 408

418 Grow extra trays for monitoring purposes and disperse them throughout the growing area to have representative samples within the nursery or greenhouse. Collect about 1 pint (about 500 mls) of substrate. Add distilled water until substrate just becomes saturated with water just appearing at the top of the substrate. Be consistent with the appearance and it will not matter to what level the water saturates the substrate. Let the sample equilibrate for at least 30 minutes Carefully place probe in saturated media and measure EC and ph in sample. Dilution This method is simpler in procedure than the SME. Take one part substrate, by volume and add 1.5 parts water. Allow to sit for an hour and test liquid portion. Detailed documentation is the most important action next to monitoring. Keeping records provides a history of cultural environment for use later if or when problems arise. With all these monitoring programs, develop a habit of regular record keeping, and always have records easily available. Table 25.2 Interpreting Electrical Conductivity Values From Different Methods These EC recommendations are adapted from On-site Testing of Growing Media and Irrigation Water, a British Columbia Ministry of Agriculture fact sheet revised in Values have been adjusted to meet present fertility strategies. Values differ greatly within Indication levels, and merely serve as a guideline. Experience is necessary with each of these methods. 1:5 1:1.5 SME Pour Through 1 Indication 0 to to to to 0.50 Low nutrient levels may not be sufficient for some plants. High-end of range suitable for seedlings and salt sensitive plants to to to to 2.0 Normal Standard root range for most established plants. Lower-end of range typical for normal fertility to to to to 4.6 High suitable for salt tolerant plants but mid to high end of this range may damage roots to to to to 6.5 Very High May result in salt injury, reduced growth and root death. Dilution or Leaching by irrigation necessary. > 1.1 > 3.5 > 4.5 > 6.6 Extreme Immediate leaching is required. 1 Due to the variability of the Pour Through technique results, growers should always compare their results to the SME method to establish acceptable ranges. 409

419 Making Home-Made Substrate Start by finding components like the ones listed at the beginning of this chapter that will give adequate moisture retention, but are porous enough to permit the exchange of oxygen. The mix should have a low initial electrical conductivity, and should have some ability to freely exchange nutrients with the plant roots. The substrate should be stable, able to resist breaking down, and free of pathogens. Finally, a substrate that is reliably consistent with these properties from batch to batch is important so continual adjustment of management strategies, especially irrigation will not be necessary. Some typical recipes are as follows: Germination and annual mixes should have a relatively high water holding capacity because the plants are growing in small containers with limited volume like plug trays or cell-packs. Plant containers larger than plug and cell packs may require substrate components with larger particle sizes like pine bark. The following are typical substrates with a wide range of component ratios by volume, depending on the plants being grown or the containers in which they are grown. Germination, Annual, and Bedding Mixes for plug trays and cell packs 0-20% Pine Bark, 40-80% Sphagnum Peat, 10-40% Perlite, with dolomitic lime and gypsum Perennial Mixes for containers 1 gallon or less in size: 25-60% Pine Bark, 40-60% Sphagnum Peat, 0-40% Perlite with dolomitic lime, and gypsum Woody Shrubs and Trees for containers of a gallon or more % Pine Bark, 0-30% Sphagnum Peat, 0 to 20% concrete grade sand, with dolomitic lime, and gypsum. Other components or amendments that may be considered for incorporation in the mix are nutrients in the form of controlled release fertilizers or micronutrient charges. Substrates with pre-incorporated controlled release fertilizers should be utilized quickly and should not sit for more than a week or two. Substrates exposed to rain and sun, particularly with large piles, incorporated controlled release fertilizer may begin to release fertilizer salts into the substrate. A very high electrical conductivity may result and this could kill tender new roots after potting. Be sure to consistently monitor substrates with preincorporated fertilizers for ph and EC, especially before potting. Surfactants or wetting agents are often utilized in commercial substrates to aid in irrigation, especially if substrates become dry. Consider using these materials to help get the substrates wet after potting, and to assist irrigation during the crop cycle. They are available in liquid and granular form. Monitoring Equipment, Care and Calibration Hand held ph and EC sensors are available from a variety of manufacturers. These are necessary for substrate monitoring. Most good ph and EC probes need care and calibration. Many are made of glass membranes, which need to remain moist and be contained in a special buffer solution. After purchasing a ph and EC probe, remember to also purchase electrode buffer solution, and calibration solutions for both electrical conductivity and ph (7.01 and 4.01). Different EC meters require different calibration solutions. Remember to inquire about which calibration solutions to purchase for the EC probe as they come in several different strengths. 410

420 References Bailey, D. and T. Bilderback Alkalinity Control for Irrigation Water Used in Nurseries and Greenhouses. HIL # Day, S.D., J.R. Harris, and S.B. Dickinson Basic Overview of Soils and Substrates. In Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. Eds. Lea-Cox, J., D. Ross, and A. Ristvey. College Park, Maryland. Day, S.D., S.B. Dickinson, and J.R. Harris Physical Properties of Substrates. In Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. Eds. Lea-Cox, J., D. Ross, and A. Ristvey. College Park, Maryland. Dickinson, S.B., J.R. Harris, and S.D. Day Substrate, Materials and Ecology. In Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. J.D Lea-Cox and D. Ross (Eds.) University of Maryland, College Park, Maryland. Dickinson, S.B., S.D. Day, and J.R. Harris Chemical Properties of Substrates. In Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. Eds. Lea-Cox, J., D. Ross, and A. Ristvey. College Park, Maryland. Handreck, K.A. and N.D. Black Growing media for ornamental plants and turf. 3rd ed. University of New South Whales Press. Randwick, Australia. 448p. Wallach R Physical Characteristics of Soilless Media. In Soilless Culture: Theory and Practice. Eds. Raviv, M. and J Heinrich Lieth. Elvselvier, Boston. Pp

421

422 Part 6 Appendix Appendix A Appendix B Appendix C Selected Resources Conversion Factors Images of Insects, Diseases, Weeds and Abiotic Problems

423

424 Appendix A Selected Resources Resources Available for Greenhouse Production The following is a selection of resources for commercial horticulture production. Included here are books, fact sheets, magazines, and websites applicable to greenhouse production and pest management. This list is by no means complete. Land-grant university extension websites have publications sections with a wealth of information about commercial horticulture. Internet searches can be an effective way to find additional information. Greenhouse IPM Publications Herbaceous Perennials Production: A guide from propagation to marketing (NRAES-93) Integrated Pest Management for Bedding Plants: A Scouting & Pest Management Guide Cornell University New England Greenhouse Floriculture Guide: A Management Guide for Insects, Diseases, Weeds, and Growth Regulators Guide to Insects and Related Pests of Floriculture Crops in New England New England Vegetable Management Guide UMass Extension Bookstore Rutgers Greenhouse Cost Accounting and Software Websites University of Maryland College of Agriculture and Natural Resources IPMnet: Commercial Ornamental Horticulture, University of Maryland Extension Home and Garden Information Center, University of Maryland Extension California Department of Pesticide Regulation, Environmental Monitoring and Pest Management Suppliers of Beneficial Organisms in North America (1997): 415

425 Crop Data Management Systems (CDMS) - Pesticide labels online Biological Control A Guide to Natural Enemies in North America (Cornell University) Maryland Nursery, Landscape, and Greenhouse Growers Association Maryland Department of Agriculture Plant Industries and Pest Management Links to pesticide regulation, plant protection, and weed control NPIC Product Research Online (NPRO) University of California: Floriculture and Ornamental Nurseries - Biological Control Disease Test Kits Test kits for Pythium, Rhizoctonia and Phytophthora Neogen Corporation 620 Lesher Place, Lansing, MI , INSV Test Kits Agdia, Inc County Road 6, Elkhart, Indiana, , Hydros, Inc. Envrionmental Diagostics - Disease test kits: Substrate Testing Laboratories University of Delaware Soil Testing Program, , 152 Townsend Hall, 531 S. College Avenue, Newark, DE, , Virginia Tech Soil Testing Laboratory, , 145 Smyth Hall (0465), Blacksburg, VA 24061, A&L Eastern Agricultural Laboratories, Inc., , 7621 Whitepine Road, Richmond, VA 23237, Pennsylvania Agricultural Analytic Services State University Laboratory University Park, PA

426 JRPeters Laboratory Testing Services 6656 Grant Way, Allentown, PA , North Carolina State University Horticultural Substrates Laboratory 152 Kilgore Hall, Box 7609, Raleigh, NC , Disease Testing Laboratories: A sample of any plant suspected to be infected with disease can be sent to a commercial laboratory. Viruses can be detected via laboratory assays, such as Tomato spotted wilt virus and Impatiens necrotic spot virus, both transmitted by thrips. These two viruses can cause disease in many plants, with symptoms that can be mistaken for nutritional disorders, fungal diseases, or other problems. Other viruses that most often occur in ornamentals are cucumber mosaic virus (transmitted by aphids), and tobacco and tomato ringspot viruses (transmitted by nematodes), seeds or by propagating infected plants. Agdia Testing Services: ELISA and PCR disease testing County Road 6 Elkhart, Indiana , Penn State Plant Disease Clinic Sara May, Coordinator 220 Buckout Laboratory, University Park, PA , srm183@psu.edu, University of Delaware Plant Diagnostic Clinic Nancy Gregory, Diagnostician 151 Townsend Hall, Newark, DE , University of Maryland Plant Diagnostic Lab Karen Rane, Director 4112 Plant Sciences Building, College Park, MD , VPI Plant Disease Clinic Mary Ann Hanson and Elizabeth Bush, Co-Directors Department of Plant Pathology, Physiology, and Weed Science 106 Price Hall, Blacksburg, VA , Sources for Pesticide Information, Biologicals Chemical & Pharmaceutical Press, Inc. s Greenbook Pesticide labels ( Crop Data Management Systems, Inc. Pesticide labels ( EXTOXNET The EXtension TOXicology NETwork Pesticides: Toxicology, Technical Information from UC Davis, Oregon State Univ., Michigan State, Cornell Univ., Univ. of Idaho, Environmental Protection Agency s Office of Pesticide Programs, 417

427 Appendix B Conversion Factors Multiply By To Obtain Multiply By To Obtain Acres Hectares Kilograms 1,000 Grams Acres 43,560 Square feet Kilograms Pounds Acres 4,840 Square yards Kilograms per meter Pounds per foot 2 Acres Square miles Kilograms per meter Pounds per inches 2 Acres 4,047 Square meters Kilograms per meter Grams per centimeter3 Acres Hectares Kilograms per meter Pounds per foot 3 Atmospheres 14.7 Pounds per inch2 Kilograms per meter Pounds per inches 3 Atmospheres 10,333 Kilograms per meter2 Kiloliters 1,000 Liters Centimeters Feet Kilometers 100,000 Centimeters Centimeters.3937 Inches Kilometers 3,281 Feet Centimeters.01 Meters Kilometers 1,000 Meters Centimeters 10 Millimeters Kilometers.6214 Miles Centimeters Mils Kilometers 1,093.6 Yards Cubic centimeters Cubic feet Kilowatt hours 3,415 BTUs Cubic centimeters Cubic inches Kilowatt hours Horsepower hours Cubic centimeters.0001 Cubic meters Kilowatts BTUs per minute Cubic centimeters Cubic yards Kilowatts Horsepower Cubic feet 28, Cubic centimeters Kilowatts 1,000 Watts Cubic feet 1,728 Cubic inches Liters 1,000 Cubic centimeters Cubic feet Cubic yards Liters Cubic feet Cubic inches Cubic centimeters Liters Cubic inches Cubic inches Cubic meters Liters.001 Cubic meters Cubic inches Cubic yards Liters Cubic yards Cubic yards 764,600 Cubic centimeters Liters.2642 Gallons Cubic yards 27 Cubic feet Liters Quarts (fluid) Cubic yards.7646 Cubic meters Lux.0929 Foot-candles Feet Centimeters Meters 100 Centimeters Feet 12 Inches Meters Feet Feet.3048 Meters Meters Inches Feet.333 Yards Meters.001 Kilometers Foot-candles Lux Meters 1,000 Millimeters Gallons Liters Meters Yards Gallons 128 Ounces (fluid) Milligrams.001 Grams Gallons 8 Pints (fluid) Milligrams Kilograms Gallons 4 Quarts (fluid) Milligrams per liter 1 Parts per million Gallons per minute.134 Cubic feet per minute Milliliters 1 Cubic centimeters Gallons per minute Cubic feet per second Milliliters.001 Liters Gallons per minute Liters per second Millimeters.1 Centimeters Grams.001 Kilograms Millimeters Inches Grams 1,000 Milligrams Millimeters.001 Meters Grams Pounds Ounces (fluid) Cubic inches Grams per liter.1336 Ounces per gallon Ounces (fluid) Gallons Grams per liter.0334 Ounces per quart Ounces (fluid) Liters 418

428 Multiply By To Obtain Multiply By To Obtain Grams per liter 1,000 Parts per million Ounces (fluid) Milliliters Hectares Acres Ounces (fluid) 2 Tablespoons (fluid) Hectares 107,000 Square feet Ounces (fluid) 6 Teaspoons (fluid) Inches Centimeters Parts per million.001 Grams per liter Inches Feet Parts per million 1 Milligrams per kilogram Inches.0254 Meters Parts per million 1 Milligrams per liter Inches Yards Parts per million.013 Ounces per 100 gallons Parts per million.0083 Pounds per 1,000 gallons Quarts (fluid).9463 Liters Pints (fluid) Cubic centimeters Quarts (fluid) Milliliters Pints (fluid).0167 Cubic feet Quarts (fluid) 32 Ounces (fluid) Pints (fluid) Cubic inches Quarts (fluid) 2 Pints (fluid) Pints (fluid).125 Gallons Square centimeters Square feet Pints (fluid).4732 Liters Square centimeters.1550 Square inches Pints (fluid) 16 Ounces (fluid) Square centimeters.0001 Square meters Pints (fluid).5 Quarts (fluid) Square centimeters 100 Square millimeters Pounds Grams Square feet Acres Pounds Kilograms Square feet 929 Square centimeters Pounds 16 Ounces Square feet 144 Square inches Pounds per cubic foot Grams per centimeter 3 Square feet.0929 Square meters Pounds per cubic foot Kilograms per meter 3 Square feet.111 Square yards Pounds per cubic foot Pounds per inch 3 Square inches Square centimeters Pounds per cubic inch 27,680 Kilograms per meter 3 Square inches Square feet Pounds per cubic inch Pounds per centimeter 3 Square inches Square millimeters Pounds per cubic inch 1,728 Pounds per foot 3 Square meters Acres Pounds per foot Kilograms per meter Square meters Square feet Pounds per inch Grams per centimeter Square meters Square yards Pounds per square foot Kilograms per meter 2 Square millimeters.01 Square centimeters Pounds per square foot Pounds per inch 2 Square millimeters Square inches Pounds per square inch Kilograms per centimeter 2 Square millimeters Square meters Pounds per square inch Kilograms per meter 2 Square yards Acres Pounds per square inch 144 Pounds per foot 2 Square yards 9 Square feet Quarts (fluid).0334 Cubic feet Square yards 1,296 Square inches Quarts (fluid) Cubic inches Square yards.8361 Square meters Quarts (fluid).25 Gallons 419

429 Appendix C Images of Insects, Diseases, Abiotic Problems and Weeds Insects: Beneficial Insects and Organisms Aphids Caterpillars Fungus Gnats Shoreflies Leafminers Mites Mealybug Scale Thrips Whitefly Diseases: Foliar Diseases Root Rots Weeds: Abiotic Problems: 420

430 Aphidius wasp with cabbage aphids Photo: Suzanne Klick Aphidius wasp mummies (parasitized aphids) Photo: Suzanne Klick Lady bird beetle larva on cabbage Photo: Suzanne Klick Adult lady bird beetle, Hippodamia convergens Photo: Suzanne Klick Lacewing, Chrysoperla sp., larva Photo: Suzanne Klick Lacewing, Chrysoperla sp., adult Photo: Suzanne Klick 421

431 Syrphid fly larva Photo: Suzanne Klick Syrphid fly adult Photo: Suzanne Klick Aphidoletes (fly midges) feeding on aphids Photo: Suzanne Klick Minute pirate bug nymph Photo: Stanton Gill Sachet containing predators of thrips Photo: Suzanne Klick Whitefly infected with Beauveria bassiana Photo: Stanton Gill 422

432 Distorted foliage from aphids feeding on zinnia Photo: Suzanne Klick Honeydew and aphid cast skins on snapdragon Photo: Suzanne Klick Sooty mold from aphids on celosia Photo: Suzanne Klick Root aphids on aster roots Photo: Shannon Wadkins Cabbage aphid with characteristic waxy coating Photo: Suzanne Klick Close-up of green peach aphid (peach color form) Photo: Suzanne Klick 423

433 Petunia damaged by European pepper moth larva Photo: Suzanne Klick Webbing caused by European pepper moth larva Photo: David Clement Wilting caused by European pepper moth larva Photo: Suzanne Klick Girdling of poinsettia by European pepper moth Photo: Suzanne Klick European pepper moth larva Photo: Suzanne Klick European pepper moth caught in pheromone trap Photo: Suzanne Klick 424

434 Imported cabbageworm, Pieris rapae, larvae Photo: Suzanne Klick Imported cabbageworm, Pieris rapae, adult Photo: Suzanne Klick Imported cabbageworm pupa Photo: Suzanne Klick Cabbage looper larva Photo: Shannon Wadkins Corn earworm, Helicoverpa zea, larva Photo: Suzanne Klick Cross-striped cabbageworm, Evergestis rimosalis Photo: Suzanne Klick 425

435 Variegated fritillary, Euptoieta claudia, larva Photo: Suzanne Klick Variegated fritillary, Euptoieta claudia, butterfly Photo: Suzanne Klick Yellowstriped armyworm on mum Photo: Suzanne Klick Heavy infestation of fungus gnats on yellow cards Photo: Stanton Gill Fungus gnat larva feeding on pansy at base of stem Photo: Suzanne Klick Fungus gnat damage on poinsettia cutting Photo: Suzanne Klick 426

436 Shorefly adult Photo: Suzanne Klick Leafminer damage on gerbera Photo: Suzanne Klick Leafminer damage on cabbage Photo: Shannon Wadkins Blotch leafminer damage on mum Photo: Suzanne Klick Blotch leafminer larva found in mum leaf mine Photo: Suzanne Klick Broad mite damage on sweet potato vine Photo: Suzanne Klick 427

437 Heavy webbing on mum from spider mites Photo: Shannon Wadkins Stippling damage on calla lily from spider mites Photo: Suzanne Klick Twospotted spider mites and eggs Photo: Shannon Wadkins Mealybugs in cryptic areas of New Guinea impatiens Photo: Suzanne Klick Mealybug on heliconia Photo: Suzanne Klick Longtailed mealybug on palm Photo: Suzanne Klick 428

438 Brown soft scale Photo: Suzanne Klick Cactus scale on Opuntia dillenii Photo: Suzanne Klick Hemispherical scale on palm Photo: Suzanne Klick Fern scale on staghorn fern Photo: Suzanne Klick Slug damage on dahlia Photo: Suzanne Klick Slug on bottom of pot Photo: Suzanne Klick 429

439 Streaking from thrips feeding on gerbera daisy Photo: Shannon Wadkins Western flower thrips in gloxinia flower Photo: Suzanne Klick Female western flower thrips Photo: Stanton Gill Echinothrips damage on New Guinea impatiens Photo: Suzanne Klick Echinothrips Photo: Suzanne Klick Cuban laurel thrips Photo: Shannon Wadkins 430

440 Whitefly infestation on sunflower Photo: Suzanne Klick Greenhouse whitefly, Trialeurodes vaporariorum Photo: Shannon Wadkins Greenhouse whitefly, Trialeurodes vaporariorum Photo: Suzanne Klick Greenhouse whitefly, Trialeurodes vaporariorum Photo: Suzanne Klick Pupal stage of Bemesia tabaci whitefly Photo: Suzanne Klick Bemesia tabaci whitefly on poinsettia leaf Photo: Suzanne Klick 431

441 Alternaria on zinnia Photo: Suzanne Klick Stunting/mottling from Angelonia flower break virus Photo: Suzanne Klick Bacterial leaf spot on zinnia Photo: Suzanne Klick Bacterial blight on gerbera foliage Photo: Suzanne Klick Botrytis on geranium flower Photo: Suzanne Klick Botrytis on geranium foliage Photo: Suzanne Klick 432

442 Geranium leaf infected with Botrytis Photo: Suzanne Klick Botrytis elliptica leaf spot on lily Photo: Suzanne Klick Black root rot, Thielaviopsis sp., on petunia Photo: Stanton Gill Black root rot, Thielaviopsis sp., infecting petunia Photo: Suzanne Klick Downy mildew infecting basil Photo: David Clement Downy mildew spores on underside of basil leaf Photo: David Clement 433

443 Downy mildew causing poor growth on coleus Photo: Suzanne Klick Downy mildew on upperside of coleus foliage Photo: Suzanne Klick Downy mildew on underside of coleus foliage Photo: Suzanne Klick Japanese anemone infested with foliar nematodes Photo: Suzanne Klick Impatiens necrotic spot virus (INSV) on orchid Photo: Suzanne Klick New Guinea impatiens infected with INSV Photo: Karen Rane 434

444 Garden impatiens infected with INSV Photo: Suzanne Klick New Guinea impatiens infected with Myrothecium Photo: Ethel Dutky Uneven stem growth from poinsettia scab infection Photo: Stanton Gill Poinsettia scab infection on poinsettia leaves Photo: Stanton Gill Heavy powdery mildew infection on sedum foliage Photo: Suzanne Klick White powdery mildew spores on gerbera leaves Photo: Suzanne Klick 435

445 Powdery mildew on zinnia foliage Photo: Suzanne Klick Pseudomonas sp. infection on celosia Photo: Suzanne Klick Pseudomonas sp. infection on tomato Photo: Suzanne Klick Wilting poinsettia plant due to Pythium root rot Photo: Suzanne Klick Close-up of poinsettia roots infected with Pythium Photo: Suzanne Klick Pythium root rot on salvia plugs Photo: Suzanne Klick 436

446 Vinca stem damaged by Rhizoctonia Photo: Suzanne Klick Webbing at base of lisianthus caused by Rhizoctonia Photo: Stanton Gill Chrysanthemum white rust on topside of foliage Photo: Karen Rane Chrysanthemum white rust on bottom of foliage Photo: Karen Rane Rust spores on the underside of a snapdragon leaf Photo: Suzanne Klick Yellowing/spotting caused by rust on snapdragon Photo: David Clement 437

447 Tobacco mosaic virus symptoms on petunia Photo: Karen Rane Tobacco mosaic virus symptoms on calibrachoa Photo: Karen Rane White mold infecting plants in hanging basket Photo: Suzanne Klick Pepper foliage infected with Xanthomonas Photo: Suzanne Klick Cold damage on Aglaonema foliage Photo: Shannon Wadkins Cold damage on petunia in hanging basket Photo: Shannon Wadkins 438

448 Oedema on primrose foliage Photo: Suzanne Klick Oedema on geranium leaves Photo: Suzanne Klick Iron chlorosis on pansy Photo: Suzanne Klick Spray damage on poinsettia foliage Photo: Suzanne Klick Iron/manganese toxicity on geranium due to low ph Photo: Suzanne Klick Bird s nest fungus in pot Photo: Suzanne Klick 439

449 Moss growing in pot Photo: Suzanne Klick Spurge that germinated in pot of begonias Photo: Suzanne Klick Groundsel under benches harboring aphids Photo: Suzanne Klick Groundsel that has gone to seed Photo: Suzanne Klick Weeds, with insect damage, under bench Photo: Suzanne Klick Oxalis, a common greenhouse weed, in flower Photo: Suzanne Klick 440