TPM/IPM Weekly Report

Transcription

1 TPM/IPM Weekly Report for Arborists, Landscape Managers & Nursery Managers Commercial Horticulture April 12, 2013 In This Issue... - Ambrosia beetles - Gymnosporangium rusts - Fire blight - Hemlock woolly adelgid - White prunicola scale - Sapsucker damage - Scab alert - Eastern tent caterpillars - Boxwood leafminer - Lichen on trees and shrubs - Indian wax scale and mantid egg case - Spider mites on cherry laurel Beneficial of the Week Weed of the Week Plant of the Week Degree Days Phenology Contacts for Questions Conferences Integrated Pest Management for Commercial Horticulture ipmnet.umd.edu Conferences Publications Archived IPM reports If you work for a commercial horticultural business in the area, you can report insect, disease, weed or cultural plant problems found in the landscape or nursery to sklick@umd.edu Coordinator Weekly IPM report: Stanton Gill, Extension Specialist, IPM for Nursery, Greenhouse and Managed Landscapes, sgill@umd.edu (office) or (cell) Regular Contributors: Pest and Beneficial Insect Information: Stanton Gill and Paula Shrewsbury (Extension Specialists) Disease Information: Karen Rane (Plant Pathologist) and David Clement (Extension Specialist) Weed of the Week: Chuck Schuster (Extension Educator, Montgomery County) Cultural Information: Ginny Rosenkranz (Extension Educator, Wicomico/ Worcester/Somerset Counties) Fertility Management: Andrew Ristvey (Regional Specialist, Wye Research & Education Center) Design, Layout and Editing: Suzanne Klick (Technician, CMREC) Ambrosia Beetles We pulled beetles from our ethanol alcohol baited Lindgren traps Tuesday morning and there were 112 Xylosandrus germanus adults in the traps. We also counted three Xylosandrus crassiusculus (granulated ambrosia beetles). Last week we had all zeroes in the baited traps. These two invasive species of ambrosia beetles have been reported on over 200 species of plants. Hosts include: beech, birch, holly, honeylocust, elm, chestnuts, linden, maple, oak, planetree, yellowwoods, sweetgum, tulip tree, and willow, Japanese silver bell trees, apple, ash, black cherry, black walnut, cedar, dogwood, grape, pear, pecan, pine, plum, poplar, and rhododendron. On Monday, we had our first ambrosia beetles showing up, but these beetles were mainly native species. With the sudden rise in temperatures we had a swarm of activity around the alcohol traps. If your nursery has had problems with these two species of ambrosia beetles, then in the next couple of days you need to get a protectant spray of Onyx (Bifenthrin) on the trunk of susceptible species of plants. Steve Frank, North Carolina State University, just presented his work on ambrosia beetle control in North Carolina. Steve found that a protectant spay of a pyrethroid such as bifenthrin gave protection for three weeks. We will continue to monitor adult activity and if they are still active in three weeks you might want to consider a second application to protect the trees.

2 Follow up to the Ambrosia Beetle Activity Alert we sent on Tuesday: The Heat Is Bringing Them Out Ethyl alcohol infused tree bolts were set out in Frederick County. They were checked on Tuesday and ambrosia beetles were found rapidly drilling into the heartwood. Hopefully anyone who wants to protect their susceptible nursery trees got their bifenthrin (Onyx) application on the trunks of the trees. This protective spray should provide three weeks of control. Maria Rojas sent in samples from Darnestown and Frederick County on Thursday morning. Xylosandrus germanus was found at the Frederick County site and X. germanus and the granulate ambrosia beetle was found at the Darnestown site. These reports confirm that we have a lot of flight activity of these two invasive species of ambrosia beetles this week. Gymnosporangium Rust Diseases The rain today and the warm weather earlier in the week is making conditions pretty ideal for gymnosporangium rust diseases. Glenn Gladders, Delaware Forest Service, had his first report of cedar-apple rust today. David Clement, HGIC, found galls starting to sporulate today in Howard County. Cornell University has a good fact sheet on this disease with control suggestions. Here is excerpt from the factsheet: Before apple can be infected, adequate moisture must be present in a temperature range of 8-24 C (46-75 F) to allow for formation of basidiospores on cedar galls. Then, the basidiospores will infect apple when susceptible leaf and fruit tissues are wet for certain lengths of time at specific temperatures. Leaves are most susceptible to infection when 4-8 days of age, and fruit are susceptible from tight cluster through bloom. Susceptible apples and pear can receive an application of Manzate or Mancozeb. Gymnosporangium gall just starting to sporulate (April 12, 2013) Photo: David Clement, HGIC The information from Cornell University is available at Fire Blight Fire blight (Erwinia amylovora) for the last 3 springs has been causing dieback of branches in many nurseries. Rainy periods during open bloom time and warm, humid weather have made conditions ideal for the spread of this bacterial disease. Bees carrying pollen from plant to plant often carry the bacterial disease in the soft tissue of the bloom and it progresses from the flower down into the branches. Fire blight is destructive to nursery trees such as Amelanchier, crabapple, apple, and quince trees and is the most serious pear disease in the Eastern United States. In the past 3 years significant losses to the apple industry have resulted due to this disease. In 2013, we saw heavy dieback in Amelanchier in nurseries. The disease can attack some 75 species of plants in the rose family. Fire blight also occurs frequently on pyracantha, spirea, hawthorn, and mountain ash. In fruit trees, the disease can kill blossoms, fruits, shoots, limbs, and tree trunks. Certain varieties of apple are more susceptible than others. Susceptible varieties include Gala, Ginger Gold, Braeburn, Jonathan, Rome, Yellow Transparent, and Idared. Some apple varieties such as Enterprise, Goldrush, Topaz, Liberty and Freedom have been selected to be resistant to fire blight. For information on the life cycle and management of this disease, go to the Cornell University fact sheet at 2

3 Hemlock Woolly Adelgid Alisa DeGeorge sent a photo of hemlock woolly adelgid with eggs under the fluffly, white wax. Look for activity of the reddish brown crawlers over the next few weeks. Control: Small trees (under 20 ft) that can be thoroughly covered with a spray can have an application of 2% horticultural oil or insecticidal soap applied to crawlers or newly settled crawlers. Acetamiprid (Tristar) can be applied as a foliar spray. Imidacloprid (Merit) can be applied as a soil drench or soil injection. It takes 60 days for imidacloprid to become toxic in the plant before controlling the pest. Make sure the soil has adequate soil moisture at the time of application. Do not apply imidacloprid during drought conditions unless the area is thoroughly irrigated after an application. Applications can be made in the fall or early spring. Dinotefuran (Safari) can be applied as a soil drench. It takes about 2-3 weeks for uptake of dinotefuran. Hemlock woolly adelgid Photo: Alisa DeGeorge White Prunicola Scale on Cherry Laurel Examine your customers cherry laurels. We are receiving a lot of photos of branches encrusted with white prunicola scale, Pseudaulacaspis prunicola. This armored scale has been taking off on cherry laurel over the last couple of years. It also gets on cherry and lilac and we have seen an increase in this scale on these plants. It has also been reported on boxwood as well. The fertilized females have round covers and overwinter. The body of the female under the cover is a yellow-orange color. Females usually start producing crawlers in early to mid-may and these crawlers are usually emerging for at least three weeks. There are usually have three generations per season. Davidson and Miller (Armored Scale Insect Pests) report the adults (2nd generation) starts in early June with these adults producing eggs by the last of June. Second generation crawlers should be out in early July with 2nd generation adults present by early August. The egg laying for the 3rd generation is around mid-august with crawlers by late August. This timeline gives a rough estimate of when to check for crawler activity. We will monitor in 2013 and try to fine tune this timing for you as the season goes progresses. We have several sites that we will be monitoring so we can tell you when the crawlers emerge. Control: If your cherry laurel is still dormant, then a 3 4% horticultural oil can be used to reduce the overwintering female populations. When crawlers are present, use either Distance or Talus to control the early life stages. Overwintering female cover removed to show body underneath Heavy infestation of white prunicola scale on cherry laurel 3

4 Sapsucker Damage Jeff Schwartz sent in these pcitures of viburnum with rows of wounds on the branches. This is sapsucker damage. Steve Arrington, Sun Nurseries, also reported this damage on 20-year old sugar maples planted as street trees. Steve noted that three out of twelve had this damage. This migratory bird does the damage in the fall before it migrates south for the winter. They seem to favor viburnum stems. Sapsucker damage on leatherleaf viburnum Photo: Jeff Schwartz, Ashton Manor Environmental Sapsucker damage on sugar maple planted as a street trees Photo: Steve Arrington, Sun Nurseries Sapsucker damage on Ilex x Nellie Stevens Photo: Steve Castrogiovanni, Mead Tree Experts Scab Alert Many of you have customers with home tree fruit plantings or susceptible crabapples and might find this alert from Penn State University useful in your work. Penn State Extension is reporting that Green tip is here and the next ten days are forecasted to be ideal conditions for apple scab infection. Growers are encouraged to apply protectant fungicides during this critical period. More details are available at The 2013 Spray Bulletin for Commercial Tree Fruit Growers is a spray guide for Maryland, West Virginia and Virginia and is available at 4

5 Eastern Tent Caterpillars Eastern tent caterpillars continue to hatch and develop in Maryland. Marie Rojas, IPM Scout, found very early instars in small tents in the crotches of various species and cultivars of Malus in Frederick County. Control: Remove and destroy the tents. Bacillus thuringiensis (Bt) can be used on young caterpillars. Other options include Confirm (tebufenozide), Acelepryn (chlorantraniliprole), and Conserve (spinosad). Boxwood Leafminer Marie Rojas, IPM Scout, is finding boxwood leafminer activity in Beallsville.The boxwood leafminer have not pupated yet. They are in Buxus Green Mountain. Leafminer has also been reported to still be in the larval stage in Ellicott City and Silver Run. The larvae are yellow and turn orange when they start to pupate. Look for puffy areas where the leafminer larvae are feeding. Cut into these damaged leaves to check for the stage of this insect. Adult emergence is ususually in late April in Central Maryland. Control: Imidacloprid or dinotefuran (Safari, Transtect) Larval and pupal stages of boxwood leafminer Lichen on Trees and Shrubs Marty Adams, Bartlett Tree Experts, brought in an azalea sample that had been in a landscape for about 40 years. Several in the group were covered with lichen. Bryan Lilly, Natural Elements LLC, also reported lichen on old azaleas (100+ years old). He noted that they are heavily covered in lichen from ground to tips. Lichen is most often on trees and shrubs in declining or poor heath. The lichen does not cause plant damage. Improving air circulation and good plant vigor are the best defenses against lichen. Lichen are an indicator of good air quality. Lichen on azalea Indian Wax Scale and Praying Mantid Egg Case Craig Greco, Yardbirds, Inc., sent this photo of a small hawthorn with both indian wax scale and an egg case of a Carolina mantid. The Carolina mantid is a native predator. We have been receiving steady reports of both of these insects this spring. Look for hatching mantids in early to mid May. 5

6 Spider Mites On Cherry Laurel Marie Rojas reported that on a site visit to a homeowner s landscape in Silver Spring, there was a whole row of Prunus laurocerasus heavily stippled from high spider mite populations. She noted that this was the first time she has ever seen spider mite damage on cherry laurel. Marie did point out that these plants were planted around a patio in the back yard, which was in full blazing sun and heavily over-mulched with shredded hardwood, so it was a super-stressful situation for them. Cryptomeria Scale and Japanese Maple Scale Marie Rojas checked sites with cryptomeria scale (on Abies koreana) and Japanese maple scale (on Stewartia pseudocamellia, Styrax japonicus, and Malus). Both scale are in the adult stage at this time. No eggs are present under the female covers. Beneficial of the Week, Paula Shrewsbury Pseudoscorpions are in the same class as spiders Arachnida. They are flat, pear-shaped and have two long claws with pincers that strongly resemble those of scorpions. This sounds scary but fortunately they are quite small in size (only 2 to 8 mm in length) and do not have a stinger tail as do true scorpions. While recently sampling ash trees as part of our emerald ash borer biological control project, Dave Jennings (a post doc leading the project) came across one of these cool pseudoscorpions crawling around on the bark of an ash tree. There are more than 3,000 known species of pseudoscorpions and they can be found worldwide. In general, pseudoscorpions are beneficial because they feed on prey such as small caterpillar and beetle larvae, mites, ants, small flies, and even book lice (indoors). They are pretty interesting little creatures. Pseudoscorpions have a venom gland, usually beneath one of the fingers of their pedipalps (pincers), which produces a poison used to catch and immobilize their prey. During the digestive process pseudoscorpions pour a somewhat corrosive fluid over its prey which liquefies the prey making it easier for the pseudoscorpion to consume. Pseudoscorpions also spin silk from a gland in their jaws. They use this silk to make a type of cocoon for mating and a place to spend the winter. Psuedoscorpions may live 2 to 3 years as adults. The species we found is an arboreal species and I am hoping it will eat some emerald ash borer eggs! To see a photo of a pseudoscorpion, go to Weed of the Week, Chuck Schuster Warm weather has certainly settled upon us this week. I observed a landscape management crew out working in the beds preparing them for the war on weeds and was pleased to see that the mulch had been pulled back and that the pre-emergent herbicide was being applied below the mulch. This will provide a great deterrent to weed growth. Coupled with an appropriate mulch (it was ready to go down after the application of herbicide) season long weed free landscape beds will be the appreciated by all. Broadleaf dock, Rumex obtusifolius, is showing itself currently in many landscape and turf settings. Also known as broad-leaved dock, bitter dock, bluntleaf dock, dock leaf or butter dock. I came across a very showy patch during a recent outing in Howard County. This Broadleaf dock - notice the red veins Photo: C. Schuster, UME perennial weed, very similar to curly dock, has a yellow to orange colored taproot, forms a large basal rosette, and produces a single upright stem that can reach a height of more than forty inches. Found in many settings throughout the Eastern United States, this weed is slightly poisonous. The milky sap can also cause dermatitis or blistering of the skin. The leaves have a slightly wavy edge, the lower leaves have a petiole and a red vein. Leaves progressively become smaller as they are produced up the flowering stalk or stem. The flower stem is a 6

7 reddish brown color and is ribbed. The flowers occur in clusters of racemes on the upper one third of the flower stalk and have green sepals that as they mature turn to a reddish brown. The seeds are a reddish brown in color as well. The seeds have a serrated edge and will blow in the wind or be caught on clothing or animal hair and transported. The seeds can remain viable for many years. This perennial weed is difficult to control. When working in landscape settings, Snapshot (trifluralin and Isoxaben) and Gallery (Isoxaben) have been shown to provide good control. Post emergent control in landscapes will require products that include Burnout (Vinegar) glyphosate, clopyalid (Lontrel ), and fatty acid soaps. In turf, the use of 2, 4D or Dicamba have worked very well. Always remember that glyphosate used near roots or plant stem/trunks can lead to plant damage. 2,4D and Dicamba can volatilize and damage many species of trees and shrubs. Use proper care when using these products. Plant of the Week, Ginny Rosenkranz Spring is a time when rhododendrons bloom and Rhododendron Blue Baron is a very eye-catching cultivar. Blue Baron is a small-leafed evergreen rhododendron with flowers that are broadly funnel-shaped with wavy edges. They are held in a dome-shaped group of 5-20 and are a striking violet-blue in color. Blue Baron blooms in mid to late spring, April to May and grows well in USDA zone 6-8. Glossy green leaves are fine textured and can turn a bronze green during the winter months. Unlike many rhododendrons, the small leafed Blue Baron prefers to be planted in full or part sun, but will need moist but well drained rich, acidic, humus soils. Shallow rooted plants like the rhododendrons will need about 1-2 inches of mulch to control weeds and maintain soil moisture; too much mulch will bury the plant and stress the roots. Rhododendron Blue Baron is very compact, growing 3-4 feet tall and maturing to an ultimate height of 6 feet. Like many rhododendrons, the disease pests include Botryosphaeria canker, petal blight, azalea gall, powdery mildew. Insects include azalea lace bug, aphids and black vine weevil, Rhododendron Blue Baron Photo: Ginny Rosenkranz, UME Degree Days (As of April 11) Baltimore, MD (BWI) 93 College Park 125 Dulles Airport 107 Frostburg, MD 67 Martinsburg, WV 100 National Arboretum 125 Reagan National 125 Salisbury 132 To check degree day (DD) accumulations in your local area go to: 7

8 Plant Phenology: What is in bloom PLANT PLANT STAGE (Bud with color, LOCATION First bloom, Full bloom, First leaf) Dirca palustris (Eastern leatherwood) First bloom Silver Run (April 11) Lamium amplexicaule (henbit) First bloom Ellicott City (April 11) Lamium purpureum (purple deadnettle) Full bloom Ellicott City (April 8) Phlox stolonifera First bloom Columbia (March 31) Pyrus calleryana Bradford First bloom Full bloom Columbia (April 8) Clarksville (April 12) Ranunculus ficaria (lesser celandine) First bloom Ellicott City (April 8) Sanguinaria canadensis Full bloom Silver Run (April 11) Spirea vanhouttei First bloom Ellicott City (April 11) Sanguinaria canadensis Multiplex is a double flowering bloodroot Photo: Marty Adams Commercial Horticulture Industry Contact for Help With Plant Problems Diseases: Karen Rane: rane@umd.edu, Go to to find out how and where to submit suspected disease samples to her lab. Insects: Stanton Gill: sgill@umd.edu, (cell) or (office) Paula Shrewsbury: pshrewsb@umd.edu, Brian Clark: bpclark@umd.edu, (Brian covers Prince George s County) Weeds: Chuck Schuster: cfs@umd.edu, Soil Substrates Plant Fertility: Andrew Ristvey: aristvey@umd.edu, Horticulture: Ginny Rosenkranz: rosnkrnz@umd.edu, ext 106 (Wicomico, Worcester and Somerset counties) For questions from homeowners and master gardeners, contact the Home and Garden Information Center, or , or your local Extension office. 8

9 Training for Lawn Fertilization Certification in Maryland Maryland s new Fertilizer Law is designed to protect the Chesapeake Bay from excess nutrients entering its waters from a variety of urban sources, including golf courses, parks, recreation areas, athletic fields, businesses and hundreds of thousands of suburban and urban lawns. Nutrients, primarily nitrogen and phosphorus, are key ingredients in lawn fertilizer. When it rains, excess nutrients can wash off the land and into the streams and rivers that feed the Chesapeake Bay. Once in our waterways, excess fertilizers fuel the growth of algae blooms that block sunlight from reaching Bay grasses, rob the water of oxygen and threaten underwater life. Lawn fertilizer now accounts for approximately 44% of the fertilizer sold in Maryland. While certain restrictions on fertilizer use have been in place for farmers since 2001, additional stakeholder involvement is needed if Maryland is to meet the new nutrient reduction goals outlined in its Watershed Implementation Plan (WIP) to restore the Bay. Maryland s new lawn fertilizer law affects fertilizer manufacturers and distributors, lawn care professionals and homeowners. Beginning October 2013, all lawn care professionals must be certified in order to apply fertilizer in Maryland. Once the exam is taken and passed, then the license will be good for a calendar year. Re-certification conferences will be offered so people can renew their license. At this point you must obtain 2 nutrient management credits to renew the license. MDA has information posted on this law at: The University of Maryland Extension, Montgomery County is offering a 4 hour program for Lawn Fertilization Certification in Maryland on April 16, 2013 at the Montgomery County UME Office from 9:00 am 1:00 pm. Cost will be $20.00 per person Contact Chuck Schuster at cfs@umd.edu or call to register Operator Certification for Writing Nursery Nutrient Management Plans April 17th, 2013 Wye Research and Education Center, 124 Wye Narrows Road, Queenstown, MD July 10th, 2013 Central Maryland Research and Education Center, A Homewood Road, Ellicott City, MD Nursery Operator Certification for writing nursery nutrient management plans will be offered in two separate programs to accommodate growing season schedules. These training programs will assist you in writing a nutrient management plan for your nursery or greenhouse operation. You must write a nursery nutrient management plan if you use fertilizers and you gross over $2500 per year in sales. With this certification, you will be able to sign-off and submit your own plan. Call Andrew Ristvey (410) x113 for directions to Wye Research and Education Center and the Central Maryland Research and Education Center. 9

10 Each program consists of a Training Day and an Exam/Signoff Day. The Training Day will consist of learning the plan-writing process. After the Training Day you will have about 4 weeks, during which time you will study the Nursery Nutrient Management Training Manual and develop your plan. The Exam/Signoff Day will be for taking the exam and going over your newly developed plan. The process is relatively simple for small (or low-risk) operations, so if your operation size is less than 5 acres, we would strongly encourage you to think about becoming a certified operator. If your operation is larger than 5 acres, we would still encourage you to become a certified operator, even though the nutrient management process may be a little more complicated. Drs. John Lea-Cox and Andrew Ristvey will be happy to help you write your water and nutrient management plan. The first Training Day will be April 17th, 2013 at Wye Research and Education Center. We have scheduled the Exam/Signoff Day for May 15th at Maryland Department of Agriculture in Annapolis, MD. After passing the exam, you will be able to sign off on your plan and submit it. The second program s Training Day will be July 10th, 2013 at Central Maryland Research and Education Center just outside Ellicott City. We will schedule an Exam/Signoff Day for this program on the 10th of July. To express your interest in taking this training, please contact Mike Webster, Maryland Department of Agriculture at (410) Upcoming Programs MNLA Nursery Field Day June 20, 2013 Location: Waverly Farm, Adamstown, MD Contact: MNLA, CONTRIBUTORS: Stanton Gill Extension Specialist sgill@umd.edu Paula Shrewsbury Extension Specialist pshrewsb@umd.edu Karen Rane Plant Pathologist rane@umd.edu Chuck Schuster Extension Educator cfs@umd.edu Ginny Rosenkranz Extension Educator rosnkrnz@umd.edu David Clement Plant Pathologist hgic.umd.edu Andrew Ristvey Extension Specialist aristvey@umd.edu Brian Clark Extension Educator bpclark@umd.edu Thank you to the Maryland Arborist Association, the Landscape Contractors Association of MD, D.C. and VA, the Maryland Nursery and Landscape Association, Professional Grounds Management Society, and FALCAN for your financial support in making these weekly reports possible. Photos are by Suzanne Klick or Stanton Gill unless stated otherwise. The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by University of Maryland Extension is implied. University of Maryland Extension programs are open to all citizens without regard to race, color, gender, disability, religion, age, sexual orientation, marital or parental status, or national origin.