Inspector Findings in Kentucky

Transcription

1 Inspector Findings in Kentucky Volume XV, Issue I Office of the State Entomologist April Inside this issue: Emerald Ash Borer Update Eastern Tent Catepillar Egg Hatch Hemlock Woolly Adelgid Update 2 Greenhouse Virus Threats 3 Caterpillar Control Guide 6 Tree and Shrub Insecticide List 7 Insect and Mite Control 8 Armored and Soft Scales 9 Nursery Inspection Update Picture key: 1: eastern tent caterpillar egg mass, 2: Phytophthera ramorum 3: hemlock woolly adelgid 4: gypsy moth traps 5: pine shoot beetle 6: emerging emerald ash borer Pictures from

2 Page 2 Emerald Ash Borer Update 2011 By Katie Kittrell, Nursery Inspector, University of Kentucky Eastern Tent Caterpillar Egg Hatch Is Underway By Lee Townsend, Extension Entomologist, University of Kentucky In 2010 we added 3 new counties to the list of EAB infestations. Two of those counties, Boone, and Woodford were already quarantined, but Boyd County (next to Greenup) has since been quarantined. Reminder: movement of ash material from a quarantined area to a non-quarantined area is prohibited unless you have a permit. This includes firewood, wood chips, nursery stock, pallets, and non-treated lumber. If you need to move ash material from a quarantined county to a non-quarantined county, call our office at Ash may move freely within Eastern tent caterpillar (ETC) eggs, which were laid last June, are hatching just as leaf buds are swelling on wild cherry trees. Newly hatched eggs are easy to identify by the small hole that the tiny larva chews as it makes its exit. The small caterpillars will stay near the egg mass for a short time before moving to feed on expanding leaves. Eggs will continue to hatch through early April, caterpillars will be active for the next 4 to 5 weeks. ETC grow and develop as long as the temperature is above 37F; the warmer it is the faster they will grow. Cold temperatures will slow them down but the tent and a general coldhardiness of the species will keep them from being affected drastically, even if temperatures drop below freezing at night. the quarantined counties. To move ash across state lines, contact Dean Daugherty with the USDA at We will be setting 6800 purple traps across the state to monitor the spread of EAB in Our trapping area has moved south of the quarantined counties. ETC populations in the region appear to have been gradually increasing over the past few years, which happens with many insects. It is too early to tell what the 2011 level will be but it is normal for insects to be very abundant in some parts of a county and at moderate to low levels in others. In about two weeks ETC tents should be about the size of baseballs and easy to spot in trees. If control measures are needed to reduce ETC numbers, steps should be taken before the caterpillars leave their trees. New Hemlock Woolly Adelgid Detection Knox County By Lee Townsend, Extension Entomologist The now too-familiar white egg sacs of the hemlock woolly adelgid were found last week at a site in Knox county. The extent of known infestations can be seen at welcome.html. Egg laying begins before the first wildflowers bloom in early spring. Small reddish brown nymphs (also called crawlers) that hatch from groups of up to 300 eggs in March disperse from the tree or settle near the base of needles, sink their sucking mouthparts into twigs, and begin to feed on sap. The crawlers have a distinctive white fringe around their sides, their white protective covering is secreted later. These adelgids mature over the next few weeks and lay 50 to 200 eggs that will hatch in mid-april to early May. These crawlers are present during the spring flush of hemlock foliage. They settle on new growth and are inactive during the summer. Development resumes in September and partially-grown HWA spend the winter on tree branches and twigs covered by the white woolly material that they secrete. Development resumes in late winter and continues until March when these adelgids mature and begin the two generation per year life cycle again. In one year a single adelgid female could produce 90,000 offspring.

3 Page 3 The Viruses INSV and TSWV Are Threats to Production of Annuals and Vegetable Transplants in the Greenhouse By John Hartman, Extension Plant Pathologist, University of Kentucky Kentucky greenhouse growers are gearing up for production of bedding plants and vegetable transplants for spring sale. Production of these transplants may involve propagation of possibly infected overwintering stock, or movement of possibly infected plugs and transplants over long distances. Diseases caused by Impatiens Necrotic Spot Virus (INSV) and Tomato Spotted Wilt Virus (TSWV) are important causes of losses in Kentucky greenhouses producing transplants. Although the virus and thrips (the disease vector) are common, growers can avoid crop losses by aggressively controlling thrips and the viruses it spreads. INSV and TSWV are two different but closely related viruses causing similar symptoms. The most common and dramatic problems of greenhouse ornamentals in Kentucky have been due to INSV. This virus is usually the one causing disease symptoms on impatiens, New Guinea impatiens, begonias, petunias, snapdragons, cyclamen, cineraria and gloxinia. Both viruses are transmitted from plant to plant by western flower thrips. An adult thrips can infect a plant with virus after feeding for only 30 minutes. TSWV is very damaging to tobacco, tomatoes, and peppers, but it also attacks many ornamentals, most often dahlias imported from overseas, and chrysanthemums and (rarely) ivy geraniums. Both viruses have a very wide host range and both are vectored by western flower thrips. Virus Disease Symptoms. TSWV/INSV causes a wide variety of symptoms including leaf spot (Figures 1 & 2), stunting (Figures 3 & 4), foliage death (Figure 5), etches or ring spots on leaves (Figure 6), wilting, stem death, yellowing, and poor flowering. Symptoms are not very specific or consistent, and merely tell the grower that there is something wrong with the plant. Many other diseases and plant problems can cause symptoms that resemble TSWV/INSV. Virus symptoms may depend on time of year, type of plant, age of plant, plant physiological state, growing conditions at the time of infection, and strain of virus. In the U.K. Plant Disease Diagnostic Laboratory, positive diagnosis is made by testing infected plant tissue with an ELISA test based on a chemical reaction to the virus proteins. Separate tests are used to look for both TSWV and INSV because a plant may have either or both viruses. Managing INSV and TSWV on greenhouse ornamentals. Inspect incoming plant material such as plug plants for indications of thrips feeding injury, or for symptoms of TSWV or INSV infection. Most plant materials coming from suppliers are not guaranteed to be disease-free; thus your inspections are most important. Insist on good thrips control from your plant suppliers. Isolate incoming plants from all other plants in the greenhouse until certain they are free of the viruses. Separate cutting crops from seedlings. The disease frequently enters the greenhouse within vegetatively propagated plant material. Hanging baskets of infected cutting crops over seedlings can lead to bedding plant and vegetable plant losses, since the young seedlings are highly susceptible Immediately discard plants showing distinctive TSWV/INSV symptoms. Early destruction of a few infected plants may prevent an epidemic through all the susceptible plants in the greenhouse. If in doubt, throw them out. Infected plants cannot be cured. Do not vegetatively propagate infected plants. The virus can still be maintained in a crop through vegetative propagation even in the absence of western flower thrips.

4 Page 4 Plants may act as reservoirs of the virus. Flowering pot plant crops such as cyclamen can serve to carry the disease over from the fall to the following bedding plant season, as might weeds left under the benches. Eliminate weeds in and near the greenhouse which may harbor thrips and/or the virus. Consider using petunia plants as indicators to monitor for TSWV/ INSV and thrips feeding injuries; 'Calypso', 'Super Blue Magic' or Summer Madness' petunias may all be used as indicators of TSWV/ INSV. Use a yellow (NON-sticky) card to help attract the thrips to the petunias. Losses have been greatest with gloxinia, double flowered impatiens, New Guinea impatiens, begonia and cyclamen crops. Be particularly careful to keep these crops isolated from potential sources of virus. Be aware that vegetable and tobacco transplants are also susceptible to these viruses and can serve as reservoirs of infection. Manage the Western Flower Thrips (Frankliniella occidentalis). See the U.K. Plant Pathology fact sheet, PPFS-GH-2, entitled: Control of Tomato Spotted Wilt Virus and Impatiens Necrotic Spot Virus and Their Vectors, Western Flower Thrips, in Greenhouse Crops (available at plantpathology/ext_files/ ppfshtml/ppfs-gh-2.pdf). Perennial plant growers also need to aggressively attack TSWV and western flower thrips in both greenhouse and outdoor plantings, and must be aware that plants originating from greenhouse production but now planted outdoors may carry the virus. Even if the thrips do not overwinter in Kentucky, vegetatively propagating infected plants will maintain and spread the virus. Garden center operators must also be aware of the biology of TSWV and western flower thrips, especially if they keep herbaceous plants all year. Many perennials are also susceptible to the virus and attractive to thrips. An infected perennial will retain the virus until that plant dies. Figure 1. INSV-infected petunia leaves with circular necrotic spots. Figure 2. INSV spotting symptoms on New Guinea impatiens (upper left) and tomato leaves

5 Page 5 Figure 3. Stunting and necrosis of Gloxinia new growth caused by TSWV. Figure 4. Healthy (right) and stunted (left) geranium infected with INSV. Figure 5. Flat of New Guinea impatiens with spotted and necrotic foliage caused by INSV. Figure 6. Gloxinia ring pattern symptoms caused by TSWV (Texas A&M photo).

6 Page 6 Caterpillar Control Guide for Landscape Trees & Shrubs By Lee Townsend, Extension Entomologist, University of Kentucky Caterpillars are the immature stages of moths and butterflies. Egg-laying habits of the female moths affect the degree of feeding damage that can occur. Some species lay dozens to hundreds of eggs in a single mass resulting in lots of caterpillars feeding on single plant or in a small area. One egg mass can lead to significant leaf loss, stress, or unacceptable aesthetic damage to a single tree or shrub. In contrast, females of other species lay single or just a few eggs at a time but scatter them over a plant or an entire landscape so that feeding by the caterpillars same number of caterpillars may go unnoticed. Some caterpillars have very specialized feeding behaviors. For example, leaf tiers and leaf rollers use silk to bend and hold portions of a leaves into cylindrical living spaces that provide optimum temperature and humidity as well as protection from natural enemies. A few caterpillars are leaf miners; they feed inside leaves or needles. Sheltered caterpillars are protected from natural enemies and many insecticides. The caterpillar or stage of many species typically lasts for 3 to 5 weeks; about 90% of their feeding occurs during the last few days of their development. As a result, feeding damage appears to occur overnight although the insects have been present for some time. Regular inspection of foliage will aid in early detection of potentially damaging infestations. Caterpillars are cold-blooded so their feeding and development varies with air temperature, increasing during warm periods but slowly during cooler periods. This also can affect the impact of control measures. Full-grown caterpillars usually stop feeding and leave their host plant to pupate and complete their development to the adult stage. Some species, like tent caterpillars, wander for a time before and may be a temporary nuisance as they climb on houses and other structures. These large caterpillars usually are not killed by insecticide applications, even when they are sprayed directly. Caterpillar control considerations New landscape plantings should be protected from excess leaf loss to feeding caterpillars. Even moderate defoliation can make these trees and shrubs susceptible to stress from other pests or unfavorable environmental conditions, or reduce winter hardiness. Established, healthy trees are more able to withstand damage over one or two seasons. Also, their size may make an insecticide application impractical. Tolerating light to moderate caterpillar infestations (10% to 30% defoliation) on healthy, established trees and shrubs gives a chance for natural enemies to provide some control and allows a balance to develop in the landscape. Use of a broad-spectrum insecticide often causes greater or more lasting harm to beneficial insects than is does to plant feeders. Reduced natural control may lead to problems with other pests. Small caterpillars are more susceptible to insecticides than large ones that are nearly mature. Early detection of potentially damaging infestations usually means more effective control and less plant damage. Caterpillars are exposed to insecticides by eating residues on treated foliage or by coming in contact with spray droplets or treated surfaces. For example, Bt insecticides must be ingested to be toxic, simply spraying them on insects will not provide control.

7 Page 7 Tree & Shrub Insecticide Common Name Reference List 2011 Compiled by Lee Townsend, Extension Entomologist, University of Kentucky Organophosphates and carbamates (1) Contact and stomach nerve poison, broad spectrum, short residual life. Acephate - Orthene Turf, Tree & Ornamental Insecticide, ACE- CAP, Acephate Pro, Lepitect (injection); Carbaryl -Bayer Complete Insect Killer for Gardens, Carbaryl; Malathion - Ortho Malathion Plus Insect Spray, Pyrethroid / pyrethrins insecticides (3) Long residual, quick knockdown, broad spectrum except aphids and mites, low mammal toxicity. Bifenthrin Onyx, Talstar; Cyfluthrin Tempo; Cyhalothrin Scimitar; Permethrin - Astro, Tengard Neonicotinyls (4a-c) Synthetic nicotine-type insecticide mostly sap feeders, some beetles and caterpillars. Dinotefuron Safari 20 SG Sap -feeding insects, some leaffeeding beetles, some leaf miners for EAB ww/ Pentra Bark Transtect; Imidacloprid Effective against sap-feeders, some borers Merit, Xytect,: Thiamethoxam - Meridian Spinosyns (5) Fermentation product from a soil microbe, rapidly degraded in sunlight, but is stabilized on leaf surfaces. Nicotinic not 4 Relatively selective caterpillars, flies, thrips, some beetles. Spinosad Conserve SC Avermectins (6) Chloride channel activator Emamectin benzoate Treeage; Abamectin Avid, Lucid - leafminers, mites, suppression of aphids, tends to be slowacting Juvenile hormone mimics (7) May affect eggs, pupae, and offspring production of adults. Pyriproxyfen Distance IGR scales, aphid suppression Microbial gut membrane distuptor (11) Microbial toxin Bacillus thuringiensis, Bt kurstaki, Bt aizawai Fermentation product from a soil microbe, caterpillars only, broken down by sunlight, short residual, small larvae Bt, Dipel, Thuricide Unknown (26) Azadiractin - short residual, moderate spectrum Azatin XL, TreeAzin injectible for EAB, caterpillars, sawflies Acaricides (6) chloride channel activator - Avid, Lucid, Aracinate (injection) (10) mite growth inhibitors Hexythiazox Hexygon DF (23) inhibits lipid synthesis - Spiromesifen Forbid active against eggs, mobile stages, and adults (25) neuroactive - Bifenazate Floramite SC Horticultural oil (summer and dormant) Pure Spray 10E Spray Oil, Sun Spray Ultra Fine Oil Insecticidal soap denatures proteins contact insecticide against soft-bodied insects M-Pede, etc. Beauveria bassiana Naturalis L insecticidal fungus

8 Page 8 Insecticide Recommendations for Insect and Mite Control on Trees and Shrubs Compiled by Lee Townsend, Extension Entomologist, University of Kentucky This list is intended only as a starting point. Check the label for information on rates and cautions on phytotoxicity. Adelgids Bifenthrin, Insecticidal soap, imidacloprid + fluvalinate, imidacloprid Aphids Acephate, azadiractin, Beauveria, bifenthrin, carbaryl, cyfluthrin, g- cyhalothrin, l-cyhalothrin, dimethoate, malathion, permethrin, insecticidal soap, imidacloprid + fluvalinate, imidacloprid Beetles Acephate, azadiractin, Beauveria, bifenthrin, carbaryl, cyfluthrin, g- cyhalothrin, l-cyhalothrin, imidacloprid + fluvalinate, permethrin, spinosad Borers Carbaryl, dinoteofuran, permethrin, imidacloprid Caterpillars Acephate, azadiractin, Bacillus thuringiensis, Beauveria, bifenthrin, carbaryl, cyfluthrin, g- cyhalothrin, l-cyhalothrin, imidacloprid + fluvalinate, permethrin, spinosad Lace bugs Acephate, azadiractin, Bt, bifenthrin, carbaryl, cyfluthrin, g- cyhalothrin, l-cyhalothrin, imidacloprid + fluvalinate, insecticidal soap, imidacloprid Leafhoppers Azadiractin, bifenthrin, Carbaryl, cyfluthrin, g-cyhalothrin, l- cyhalothrin, imidacloprid + fluvalinate, insecticidal soap, imidacloprid Leaf miners Acephate, carbaryl, g-cyhalothrin, l-cyhalothrin, dimethoate, imidacloprid + fluvalinate, permethrin, spinosad, imidacloprid Mealybugs Azadiractin, Beauveria, bifenthrin, Carbaryl, cyfluthrin, g-cyhalothrin, l-cyhalothrin, imidacloprid + fluvalinate, malathion, permethrin, Mites Azadiractin, Beauveria, bifenthrin, carbaryl, dimethoate, permethrin (spider mites), spinosad (spider mites), insecticidal soap Plant bugs Azadiractin, Beauveria, bifenthrin, Carbaryl, l-cyhalothrin, insecticidal soap, malathion, Scale crawlers Acephate, azadiractin, cabaryl, cyfluthrin, g-cyhalothrin, l- cyhalothrin, dimethoate, imidacloprid + fluvalinate, imidacloprid + fluvalinate, insecticidal soap Sawflies Azadiractin, bifenthrin, g- cyhalothrin, l-cyhalothrin, imidacloprid + fluvalinate, spinosad, imidacloprid (suppression) Thrips Azadiractin, Beauveria, bifenthrin, cyfluthrin, g-cyhalothrin, l- cyhalothrin, dimethoate, permethrin, imidacloprid + fluvalinate, malathion, spinosad, insecticidal soap, imidacloprid (suppression)

9 Page 9 Armored scales and soft scales By Lee Townsend, Extension Entomologist, University of Kentucky Scales can be divided into basic groups: soft scales and armored scales. Mature soft scales generally have rounded bodies and produce large volumes of a liquid waste called honeydew. These deposits give leaves an unnaturally shiny appearance and may attract many insects, especially ants, wasps, and flies. Also, sooty mold fungus can grow on these sugar-rich deposits, causing leaves and branches to be black.. Many species settle and feed on leaves during the summer and move to twigs and bark to spend the winter. Examples of common soft scales in Kentucky include calico, magnolia, tuliptree, and cottony maple scales. Most soft scales have one generation each year and overwinter as partly grown nymphs. In contrast, armored scales have relatively flat bodies and live beneath a distinctly separate protective waxy covering which they secrete. The covering or scale provides a shelter that protects the female s fragile body and eggs. It also is a shield against insecticide sprays. Most armored scale species remain on twigs or branches and do not secrete honeydew. Common species include euonymus, pine needle, and obscure scales. Most have several generations each year. Cultural control Scales tend to thrive on stressed plants. Following a recommended fertility program and watering regime will promote plant health. However, over-fertilization favors scale buildup. If practical, improve plant sites to reduce stress and promote growth. Severely prune back heavily infested branches and protect new growth with insecticide applications. Insecticidal Sprays Horticultural oils kill by suffocation or after penetrating overwintering stages of the insect. Consequently, they may not be effective where several layers of scale coverings have accumulated. Dormant oils are typically applied during February or March but may not be very effective against armored scales. Highly refined supreme, superior, or summer oils can be used on many trees and shrubs during the growing season. Read the product label for guidelines on plant sensitivity and temperature restriction before buying and using these products. Insecticidal soaps are long chain fatty acids that kill susceptible insects through direct contact. Like horticultural oils, they require thorough coverage. Soaps leave no residue so repeated applications may be needed for some pests. These products may burn the foliage of sensitive plants, such as Japanese maple, so check the label for information about the plant species that you intend to treat. A variety of natural and synthetic insecticides are labeled for use as sprays to control scale crawlers on landscape trees and shrubs. While the residual life of these products is generally longer than oils and soaps, timing, coverage, and precautions on damage to some plant species are very similar to those for oils and soaps. Systemic insecticides Imidacloprid (Bayer Advanced Garden Tree & Shrub Insect Control Concentrate) is applied as a drench around the root zone of infested plants. This water soluble insecticide is taken up by the roots and transported throughout the plant where it is ingested by sap feeding insects. This provides a means of scale control without reliance on sprays. However, it may need to be applied several weeks before crawlers are active for best results. Evaluating Control The success or failure of control efforts may not be readily apparent but here are some things to check. - Dead soft scales often fall off of the plant. Live scales should produce a liquid when mashed, dead scales will be dry and not "bleed" when crushed. - New foliage of infested plants should have a healthier appearance once the scale burden has been removed. Buds should break a little earlier than when the plant was infested and expanded leaves should have normal color and turgor. - Sooty mold and shiny leaves should gradually disappear from plants that were infested with soft scales.

10 Volume XV, Issue I Nursery Inspections and Surveys 2011 Katie Kittrell, Nursery Inspector, University of Kentucky Nursery inspections will begin again in April. As usual, we will begin with greenhouse growers and then progress to include farmer s markets, garden centers and nursery operations. Page 10 As a reminder, any plant material that you receive from out of state should be accompanied by a certificate of inspection. Furthermore, plants that come from a federally quarantined area will have a federal stamp affixed to them or other appropriate documentation. Examples are plants coming from a state that has imported fire ants or gypsy moth. Once again, we will be sampling plants for P. ramorum (formerly called sudden oak death). We will be sampling 20 locations throughout the state. Plants to be sampled include Rhododendron, Viburnum, Kalmia, Chamelea, and Pieris. Select vineyards across the state will be trapped for 6 different moths as part of a grape commodity survey. As usual, we will also be surveying for gypsy moth, pine shoot beetle, and hemlock woolly adelgid. Find us on University of Kentucky Department of Entomology Office of the State Entomologist S-225 Ag Science Ctr N Lexington, KY State Entomologist - John Obrycki, Ph.D Joe Collins: Emerald Ash Borer Coordinator, pest surveys & nursery licenses Carl Harper: Slow-the-Spread gypsy moth trapping coordinator, web design & phytosanitary certificates Address service requested Katie Kittrell: EAB compliance inspections, pest surveys, nursery inspections, newsletter Janet Lensing, PhD: State Survey Coordinator Jennie Condra: nursery inspections, pest surveys Phone: (859) Fax: (859) joe.collins@uky.edu carl.harper@uky.edu katie.kittrell@uky.edu janet.lensing@uky.edu