Inspector Findings in Kentucky

Transcription

1 Inspector Findings in Kentucky Volume XII, Issue IV Office of the State Entomologist July Pests susceptible to controlbased on degree day forecasts ( )=Degree day ranges Taxus mealybug ( ) Black vine weevil ( ) Euonymus scale ( ) European elm scale ( ) Fall webworm ( ) Japanese beetle ( ) Leaf crumpler ( ) Lecanium scale ( ) Locust borer ( ) apply final spray Peach tree borer ( ) Pine needle scale ( ) Round headed apple tree borer ( ) apply final spray San Jose scale ( ) repeat applications because of overlapping generations Scurfy scale ( ) Spruce bud scale ( ) Two-spotted spider mite ( ) White marked tussock moth ( ) Willow aphid ( ) Yellow-necked caterpillar ( ) Picture key: 1-Pine tube moth 2- Orangestriped oakworm 3-pinkstriped oakworm 4-spiney oakworm 5-rust on Kentucky bluegrass 6-Brown patch Pictures 1,2,3,4 from insectimages.org

2 Page 2 Inspector Findings in Kentucky Oakworms From Insects and Diseases of Trees in the South US Forest Service Importance - These oakworms occur throughout the eastern United States. They are voracious feeders, and where abundant, quickly strip the trees of their foliage. Since defoliation takes place in late summer to fall, however, forest stands of white and red oak are generally able to survive with only minimal growth loss or crown dieback. The greatest damage is the aesthetic impact and nuisance the caterpillars create in urban areas. Identifying the Insect - The larvae of the orangestriped oakworm are black with eight narrow yellow stripes, the pinkstriped oakworm larvae are greenish brown with four pink stripes, and the spiny oakworm larvae are tawny and pinkish with short spines. Larvae are about 2 inches (50 mm) long and have a pair of long, curved "horns". The adult moths are a similar yellowish red, with a single white dot on each of the forewings. Identifying the Injury - Young larvae feed in groups, skeltonizing the leaf. Later they consume all but the main veins and usually defoliate one branch before moving onto another. Older larvae are less gregarious and can be found crawling on lawns and the sides of houses. Biology - Adult moths appear in June and July and deposit clusters of several hundred eggs on the underside of leaves. The eggs hatch within a week, and the larvae feed during July to September for 5 to 6 weeks. The pupae overwinter in the soil. The orangestriped and spiny oakworms have only one generation per year, while the pinkstriped oakworm has two generations. Control - Natural enemies generally prevent widespread defoliation. Chemical control may be needed for high value trees. Yellownecked Caterpillar Gregory Hoover, Penn State University The yellownecked caterpillar is a key pest of shade trees. It is widely distributed throughout most of the eastern United States. Generally, it feeds on basswood, paper and yellow birches, elm, honeylocust, oak, maple, mountain-ash, and walnut. This insect is also destructive on apple and other fruit trees. The adult is a reddish brown moth. The forewings are cinnamon brown and marked with irregular fine dark lines. Adults have a wingspread of about 50 mm. The larvae are black with four yellow stripes on each side (Fig. 1). Their bodies are covered with long fine whitish hairs. The head is jet black; the segment behind the head is bright yellow, hence its name. Mature larvae are about 50 mm long. When disturbed, larvae assume a threatening posture. Usually, they lift both the head and posterior tip of their bodies, making a distinctive U shape. Adults appear during June and July. Male moths may be attracted to lights. Females lay their white eggs in masses on the lower surface of leaves. Egg masses consist of 100 or more eggs. After hatching, young larvae congregate on foliage and feed in groups. During August and September mature larvae descend to the ground and burrow two to four inches into the soil where they overwinter as pupae. There is one generation per year. Larvae congregate near the ends of twigs and branches. Newly hatched larvae skeletonize the foliage. Defoliation first appears on the periphery of the tree crown. Mature larvae consume all the tissues of infested leaves, except the larger veins. Ornamental, shade, and fruit trees are seriously defoliated. Damage is seldom of importance to trees in a forest. There are several natural enemies that attack this pest. Birds such as robins feed on larvae. Predaceous bugs and parasitic flies may also attack this species. Monitor trees from mid-june through July for signs of this pest. Where possible remove foliage that contain white masses of eggs on the lower surface. If necessary, apply a registered formulation of an insecticide when larvae are small. Pine Tube Moth Rayanne D. Lehman, Penn State Univ. This minor pest of eastern white pine is best recognized by the symptoms it produces rather than by the appearance of the insect itself. Its damage is purely aesthetic and control is rarely warranted. Distribution and Hosts: Pine tube moth occurs in eastern North America, from Canada south to Florida and west to Wisconsin, throughout the range of its principal host, eastern white pine. A related species, the jack pine tube moth (Argyrotaenia tabulana), causes similar symptoms on jack, lodgepole, and whitebark pines in the Rocky Mountain states and the Canadian provinces of Alberta, Manitoba, and Saskatchewan. Identification: These small, slender moths have wingspans of 14 mm. Two off-white oblique lines are found on the reddish-orange forewings. When the moth is at rest, these wings conceal the smoky-colored hindwings and gray to tan

3 Page 3 Inspector Findings in Kentucky body. This coloration effec-tively camouflages the moths when they rest near unopened buds. The pale green larvae reach 12 mm at maturity. Identification of pine tube moth is gen-erally accomplished through symptoms, rather than examination of larvae or adults. Life History: There are two generations of pine tube moth each year in Pennsylvania. Adults emerge from overwintering pupae in early- to mid-april, about the time spruce spider mite eggs hatch (personal observation). This is several weeks earlier than the May emer-gence reported in the literature (Johnson and Lyon 1988). The second generation adults are reported to appear in July. Eggs are deposited on the needles. Upon emergence, larvae spin silk and tie 5-20 needles together to form a tube. The caterpillars lie within this silk-lined tube, moving to the open end to feed on needle tips. When the tube walls (needles) have been eaten down to 1 inch, partially developed larvae will abandon their tubes and begin constructing new ones. First and second generation larvae are active from and growing degree days (base 50 0 F), respectively (Clark 1993). When feeding and development is completed, larvae pupate inside the needle tubes. Damage: Pine tube moth is a minor pest of eastern white pine. The damage caused is purely aesthetic and may even go unnoticed until the empty tubes turn brown in late sum-mer. Rarely, specimen white pines in a landscape may appear ragged due to the action of this pest. Control is generally not warranted and would be extremely difficult since the larvae are protected inside the needle tubes. Cottony Maple Scale & Its Management David Shetlar, Ohio State University The cottony maple scale, Pulvinaria innumerabilis (Rathvon), is a highly modified insect pest that commonly attacks silver and red maples in Ohio. The scales are usually first noticed when the females produce an egg sac which appears as a 1/4 to 1/2-inch long ball of cotton. Heavy infestations can result in branches being turned completely white with the egg sacs. Like most scale insects, the nearly mature insects, the adults and the eggs are resistant to pesticides and the anxious tree owner must wait until the correct time for management. Plants Attacked Cottony maple scales reach epidemic numbers on silver maple but noticeable populations can occur on red maple. It is also known to be able to survive on other species of maple, honey and black locust, white ash, euonymus, oak, boxelder, dogwood, hackberry, sycamore, beech, elm, willow, basswood, and poplar. Damage Normally, this scale is a mere curiosity and nuisance. The white egg sacs easily attract attention and the developing scales produce honeydew. Honeydew is the excess water and sugar excreted by many plant sap-feeding insects. Honeydew is commonly mistaken for "plant sap" being dropped on cars, sidewalks and lawn furniture lying under trees. When honeydew collects on leaves and branches, bees, wasps and ants are attracted to the area. If the honeydew is allowed to remain, molds called "sooty fungus" grow on the material, turning the surface a gray-black color. Occasionally, heavy outbreaks of this scale occur, usually on weakened or stressed trees. These outbreaks can cause the death of numerous small branches and occasionally the death of a tree. Description and Life Cycle Mature cottony maple scales are small, flat, oval, brown insects without obvious legs, antennae or wings. They are firmly attached to the twigs and branches of various trees and may be 1/4 to 3/8-inch in diameter. At maturity, the females produce the white, cottony egg masses (called ovisacs) over a period of several weeks. The "cotton" is really waxy threads and the ovisac may contain over 1,500 eggs. These eggs hatch from mid-june to August and the young nymphs are called scale crawlers. These microscopic crawlers are small, flat, oval insects with two distinct eyes, short antennae and tiny legs. The crawlers walk onto the leaves and tend to attach alongside the major leaf veins, usually on the underside. Here, the nymphs produce copious amounts of honeydew and grow by molting once. By this time the scales look like two different kinds, a translucent white to pink form and a larger, flat, tan form. These are males and female scales, respectively. In September, the male scales emerge as tiny winged gnat-like insects that move around on the leaves in search of females. After mating, the males die and the females soon withdraw their mouthparts and crawl back onto small twigs and branches. Here, the reinsert their mouthparts and settle down for the remainder of their life. These females first appear greenish with a white powdery coating and they are about 1/8- inch long. By winter, they have turned buff in color and in the following spring and early summer they turn a chestnut brown. When the sap

4 Page 4 Inspector Findings in Kentucky Begins to flow in the spring, the females continue to grow and they again produce considerable amounts of honeydew. By late May to early June, the females have matured and they begin to produce their ovisacs. Control Hints This pest has numerous parasites and predators that normally keep its populations in check. However, every few years, these natural controls seem to fail and the cottony maple scale can reach epidemic proportions. Unfortunately, weak trees can be severely damaged during these outbreak years. Healthy trees often loose a few small branches and have no apparent long term problems. What makes management of this scale more difficult is the fact that insecticide applications may actually cause the scale problem to continue longer than normal. This is caused by poor timing of a pesticide application that kills most of the parasites and predators but allows survival of the resistant scale stages. Strategy 1: Cultural and Biological Control - Silver maples in restricted street lawns or suffering other stresses from drought, compacted soils, poor fertilization, etc. are the ones most likely to exhibit major branch or crown dieback. Improving the tree growing conditions will significantly help the trees survive the cottony maple scale attacks until the natural predators and parasites build up to effective levels. The most important predators are several black lady beetles that have two red spots on the upper surface. The most common one, Hyperaspis signata, has a larva that looks like a mealybug. Both the adults and larvae enter ovisacs to dine on the egg masses. This causes the ovisacs to have a very tattered look by mid- July. All of these lady beetles continue to dine on the nymphs that settle on the leaves. The settled nymphs are also attacked by several tiny wasps. These lay eggs in the nymphs and their developing larvae devour the pest from the inside out. Affected scales often turn brown or black and have tiny round emergence holes on their back surface. Strategy 2: Use "Soft" Pesticides - Soaps and horticultural oils can be very effective in managing the freshly settled crawlers. These materials also have a minimal adverse affect on the adult lady beetles and parasites already in settled crawlers. Insecticidal soaps or 1.5% horticultural oil must be applied thoroughly to the leaves, both to the underside and upper surfaces, in order to kill the scales. Soaps and oils only kill the pests on contact. Application of soaps or oils should be made in mid-july and again in early August, if additional crawlers are found. Strategy 3:Standard Insecticide Applications - Several insecticides are registered for control of scale crawlers and newly settled crawlers. These pesticides, again, often need to be applied in sufficient spray quantity to wet both the leaf upper and lower surfaces. Apply registered products in mid-july and again in the second week of August for best control. See OSU Extension Bulletin 504 for insecticides currently registered for scale crawlers. Strategy 4: Dormant Oils Sprays - Dormant oil sprays have been traditionally used to manage many scales on ornamental trees. Unfortunately, many maples are sensitive to these oil sprays and significant small branch dieback or spring leaf drop can occur, if the dormant oil was applied after the maple sap has begun to flow. Brown Patch by Paul Vincelli, Extension Plant Pathologist, University of Kentucky Brown Patch, also called Rhizoctonia blight, is a common infectious disease of turfgrass. All turfgrasses grown in Kentucky lawns can be affected by Brown Patch. However, this disease is usually destructive only in tall fescue and perennial ryegrass during warm, humid weather. While Brown Patch can temporarily harm a lawn's appearance, it usually does not cause permanent loss of turf except in plantings less than one-year old. Brown Patch disease is sometimes responsible for poor turf quality, but it is not the only cause of brown spots or bare patches in lawns. You may need to consider other possible causes of thinning or dead grass. These include: -improper fertilization -chemical injury -mower problems -dog or insect injury -localized dry spots -poor soil drainage -excessive thatch -competition from other plants -buried objects Symptoms Areas affected by Brown Patch are initially roughly circular, varying in size from one to five feet or more. During early morning hours, fine strands of grayish, cobwebby fungal growth (mycelium) may be evident at the margin of actively developing patches. This "smoke ring" disappears quickly as the dew dries. As an outbreak progresses and diseased patches coalesce affected areas may lose the circular appearance and become irregular or diffuse. On blades of tall fescue, lesions resulting from very recent infections are olive-green; as they dry, lesions become tan and are surrounded by a thin, brown border. Brown patch in perennial ryegrass causes blades to wither and collapse. Lesions initially are dark green or grayish green but quickly become tan as decayed leaves dry.

5 Volume XII, Issue IV Page 5 In Kentucky bluegrass, infected leaves exhibit elongated, irregular, tan lesions which are surrounded by a yellow or brown border. Disease Cycle Brown Patch is caused by infection of grass foliage and crowns by Rhizoctonia fungi. Rhizoctonia solani is a very common soilborne fungus and is the cause of Brown Patch symptoms in most instances. Rhizoctonia zeae can also cause Brown Patch in tall fescue under very hot, humid conditions. Rhizoctonia fungi survive the winter as tiny, brown, resting bodies (sclerotia) in the soil and thatch layer of the lawn. When environmental conditions are favorable for growth, the sclerotia germinate and produce cobwebby fungal mycelium, which is the active phase of the fungi. Rhizoctonia fungi often harmlessly colonize organic matter in the thatch. However, when stressful conditions weaken the grass, Rhizoctonia can infect the plants and cause disease. Leaf infections are the most common phase of Brown Patch, but infections of crowns and roots sometimes occur, particularly in seedlings. Rhizoctonia colonizes infected tissues and then forms new sclerotia, thus completing its life cycle. Factors Affecting Disease Development Host Tall fescue and perennial ryegrass are the lawn grasses most susceptible to Brown Patch under Kentucky conditions. Fine fescues (hard fescue, creeping red fescue, chewings fescue, and sheep fescue) and zoysia are all moderately susceptible to the disease. Occasionally, Kentucky bluegrass lawns can be affected by Brown Patch, although this grass is less susceptible than others. Seedlings of all grasses are more susceptible to infection than established plantings. Weather Brown Patch is most destructive when the weather is humid and temperatures are stressful to the grass. Thus, in cool-season grasses such as tall fescue and perennial ryegrass, the disease is most severe under high temperatures (highs above 85 F, lows above 60 F). Conversely, in warm-season grasses such as zoysia, Brown Patch is most severe in humid weather with moderate temperatures (45-70 F). Cultural Conditions Application of high levels of nitrogen fertilizer, particularly during spring and summer, favors development of Brown Patch by producing lush, succulent growth that is very susceptible to Rhizoctonia infection. Other factors increase disease severity by creating a humid environment favorable for growth of Rhizoctonia fungi. These factors include: overwatering, watering in late afternoon, poor soil drainage, lack of air movement, shade, a high mowing height, and overcrowding of seedlings. Excessive thatch, mowing when wet, and leaf fraying by dull mower blades also can enhance disease severity. Management Fertilization Apply the bulk of nitrogen fertilizer to cool-season turfgrasses in fall and early winter rather than spring or summer. Fall fertilization increases overall root growth of cool-season grasses and reduces their susceptibility to several diseases. A single fall application may be applied in November; if making two applications, October and December are good times to fertilize. Avoid overfertilizing, particularly with fertilizers high in nitrogen. Maintain adequate levels of phosphorous and potassium in the soil. Do not attempt to cure summertime outbreaks of Brown Patch with nitrogen fertilization, as this will simply aggravate the disease. Mowing Set a mower height of no greater than 2 1/2 inches. A mower height greater than this aggravates Brown Patch by reducing air circulation and allowing more leaf-to-leaf contact, conditions which permit greater fungal growth during humid weather. Mow regularly to promote air circulation and rapid drying of the turf, making the lawn environment less favorable for fungal growth. To avoid stressing the grass, mow often enough so that no more than onethird to one-half of the leaf length is removed at any one mowing. In tall fescue lawns, reducing the mower height to 2 inches or less can further reduce outbreaks of Brown Patch. However, keep in mind that lawns mowed this closely must be mowed frequently. In an actively growing tall fescue lawn mowed at 2 inches, it may be necessary to mow several times a week to prevent removal of more than one-half of the leaf length at one mowing. Never scalp the lawn from 4 inches down to 2 inches or less. During an active outbreak of Brown Patch in hot, humid weather, clipping removal can help eliminate a food base for the fungus. However, in the absence of an active disease outbreak, returning clippings to the lawn is a beneficial practice that returns nutrients to the soil. Keep the mower blade sharp. A dull blade shreds the leaves, creating an ideal site for infection. Irrigation When irrigation is necessary, wet the soil to a depth of at least four inches to promote deep rooting. Check the watering depth by pushing a metal rod or screwdriver into the soil. It will sink easily until it reaches dry soil. Avoid frequent, light waterings. These encourage the grass to develop

6 Volume XII, Issue IV Page 6 a shallow root system and frequently provide the surface moisture that Rhizoctonia fungi need to infect the leaves. If a disease outbreak is evident, water early in the day so that the leaves dry quickly. If the lawn is watered late in the day, the leaves may remain wet until morning, thus providing long periods of leaf wetness favorable for infectious fungi. Removing dew, by dragging a hose across the lawn or by very light irrigation during early morning hours, will reduce prolonged leaf wetness and remove leaf exudates that encourage disease development. Other Cultural Practices Avoid using excessive seeding rates when seeding or renovating a lawn, as overcrowding can aggravate an outbreak of Brown Patch. See the UK Extension Publication AGR-52, "Selecting the Right Grass for Your Kentucky Lawn," for information on seeding rates. Selectively prune nearby trees and shrubs to increase air movement and light penetration, thereby allowing leaf surfaces to dry more quickly. Avoid applying herbicides during an active outbreak, as these may aggravate the disease. Fungicides In an established lawn, fungicide sprays are not recommended to control Brown Patch. Cultural practices will usually do a great deal to reduce the disease. Even if an outbreak of Brown Patch occurs, crowns and roots of established plants often survive, and blighted turf begins to recover when cooler weather arrives. So an established, well-managed lawn often will recover from Brown Patch without fungicide applications. Probably the principal situation in Kentucky where judicious use of a fungicide in a home lawn is necessary is to control Brown Patch in a newly seeded lawn of tall fescue or perennial ryegrass. During the summer following a spring seeding, the immature plants can be easily killed by outbreaks of Brown Patch during hot, humid weather. Fungicide sprays may be helpful to protect tall fescue or perennial ryegrass lawns seeded the previous spring, to prevent loss of turf during the first season of growth. Under very high disease pressure, a fungicide spray may even be needed during the first summer following a seeding made the previous autumn, especially if the lawn was sown in late autumn. During the first summer of growth in a new lawn, inspect the lawn regularly during hot, humid weather and be prepared to have a certified pesticide applicator treat the yard if necessary. Cedar-Quince Rust Active in KY John Hartman, Extension Plant Pathologist, University of Kentucky Conspicuous symptoms of cedar-quince rust are appearing on fruits of hawthorn, serviceberry, and an occasional fruit of crabapple, backyard apple, and Callery pear in Kentucky landscapes. Cedar-quince rust, caused by the fungus Gymnosporangium clavipes, is one of three cedar rust fungi common to Kentucky. The other two are cedar-apple rust and cedar-hawthorn rust. Cedar rusts are widespread this year because wet spring weather favored infection of rosaceous hosts such as hawthorn and serviceberry from spores produced on infected cedars. Cedar-quince rust. Infection occurs during the spring, often when hawthorn and serviceberry trees are in flower. The inoculum (spores of the rust fungus) for these infections comes from nearby infected eastern red cedars and junipers. In spring, the fungus appears as a bright orange, gelatinous substance on these infected juniper twigs and branches. During the weeks after infection of hawthorn and serviceberry, when fruits are green and enlarging, rust-infected fruits begin to show tiny orange surface bumps indicating that they are infected with cedar-quince rust. As summer progresses, infected fruits enlarge abnormally and are covered with small white papery tubes called aecia and a dusting of orange rust spores. This fungus also infects shoots and twigs of crabapple and hawthorn and also hawthorn thorns, causing these plant parts to appear as swollen, dead shoot tips. Infected serviceberry and hawthorn fruits and other plant tissues produce spores from the aecia which are blown by the wind and can infect nearby junipers and eastern red cedars. Almost two years later, the fungus matures on juniper and produces spores to infect the rosaceous host. Cedar-quince rust (G. clavipes) does not form rounded galls on cedar like cedar-apple and cedar-hawthorn rust but instead forms perennial, spindle-shaped swellings on the twigs, on which a gelatinous, bright orange mass of spores is borne in the spring. There will be no additional cedarquince rust infections of hawthorns and serviceberries this year, but next spring, if the weather is wet, expect more rust infections on these hosts.

7 Volume XII, Issue IV Page 7 Destructive Diseases Common on Turfgrasses in Kentucky By Paul Vincelli, Extension Plant Pathologist, University of Kentucky The following is a list of diseases that are common in Kentucky on the host grasses indicated. This list includes only common diseases, and is not meant to provide a comprehensive list of all diseases diagnosed on The quiet may seem unusual but welcome as Brood XIV adults fade away. One part of their legacy will become more visible as twigs and branches begin to flag, the result of breaking due to egg-laying wounds made recently by females. Eggs turfgrasses grown in Kentucky. Kentucky Bluegrass: Leaf spot/melting out Necrotic ring spot Powdery mildew Red thread/pink patch Rust Summer patch Periodical Cicada Winds Down by Lee Townsend, Extension Entomologist, University of Kentucky In recent years, calico scales have become rampant on several landscape plants, including honeylocust, hawthorn, hackberry, sweet gum, yellowwood, dogwood, flowering crabapple, and sugar and Norway maples. Infestations are so heavy in some cases that entire twigs and stems are covered by the scales and the trees are in decline. Mature calico scales, Eulecanium cerasorum, are large, black and white globular-looking insects about the size of a pencil eraser. They have a soft, leathery body and when crushed ooze a gummy, hatch 6 to 10 weeks after they are deposited so clipping and removing flagged twigs (and the inserted eggs) may give some reduction in the numbers of nymphs that fall to the ground under individual trees and enter the soil to feed on tree roots. This may be useful Calico Scale & Borer Alert by Mike Potter and Dan Potter, Dept. of Entomology Univ. of KY wax-like fluid. The immobile, adult female is the life stage observed during the spring, attached to twigs and stems. Some people mistake them for ladybugs, which are roughly the same size. Like other scale insects, the calico scale feeds by sucking plant juices. Heavy infestations can cause premature leaf drop, branch dieback and, coupled with other stresses, eventual tree death. The mature females are now dying. Underneath them are thousands of eggs which have begun hatching into crawlers. Tall Fescue: Brown patch Dollar spot Pythium blight, Cottony blight Red thread/pink patch Rust Bermudagrass: Dollar spot Rhizoctonia large patch Spring dead spot Perennial Ryegrass: Brown patch for small trees with moderate or greater flagging that are still becoming established in the landscape. Cicada nymphs will be too small for the first few years to have an impact but by about the 6 th year (2014) could be removing enough sap to reduce tree vigor. Research had not shown a benefit to treating the soil under trees to kill nymphs The crawler stage prefers to suck plant juices from the leaves (further stressing the plant), and also excretes copious amounts of honeydew. The sticky honeydew and resultant sooty mold are cosmetically unappealing and can stain patios and car finishes, and attract wasps and other nuisance pests. Another reason to take action against the crawlers is that they can become wind borne, spreading the infestation to other trees nearby. Management It s too late to impact the mature females, which turn brown and die just before crawler hatch. However, the underlying Dollar spot Gray leaf spot Leaf spot & melting out Pythium blight, Cottony blight Red thread/pink patch Rust Poa annua Anthracnose Pythium root rot Summer patch Zoysia Rhizoctonia large patch as they fall to the ground and enter the soil. The annual or dog day cicadas are still to come but will be barely noticeable compared to what many have experienced during the past few weeks where the periodical cicada has been very abundant. eggs have hatched, and the crawlers are settling on the leaves. The yellowish, newly-hatched crawlers are tiny, but under close inspection their movement will be visible to the naked eye. Insecticide applications, timed to coincide with emergence of young crawlers, will break the cycle of development and help alleviate further plant stress. The most effective insecticides for crawler control are pyrethroids such as TalstarOne, Tempo (= Bayer Advanced Lawn & Garden Multi Insect Killer), and Scimitar (= Spectracide Triazicide). Sevin also can be used. So-so control of crawlers can also

8 be achieved with 2% horticultural oil or insecticidal soaps. Thorough coverage of infested twigs, branches and adjoining leaves is important. The hatching period lasts several weeks so a second application 2 to 3 weeks after the first may provide more complete control. Calico scales overwinter on the bark as mid-sized nymphs. To further reduce the likelihood of problems occurring next year, it may help to follow up with a dormant oil application in fall or winter to trees that were heavily infested with calico scales this year. Four serious pests of landscape trees dogwood borer, bronze birch borer, flatheaded appletree borer, and honeylocust borer are flying. The dogwood borer is the most serious pest of ornamental dogwoods, especially stressed trees in full sun. The bronze birch borer is a severe pest of European white or paper birch, especially cultivated trees under stress. Flatheaded appletree borers are major pests of red maples, hawthorns, flowering crabapple, and several other hardwoods, especially those which are newly transplanted or under stress. Honeylocust borers are serious pests of transplanted and established urban trees with limited root zones. Mated females of all four species fly to host trees and lay eggs on the bark. Management -- Borers rarely injure healthy trees or shrubs growing in their natural environments. When transplanted into landscape settings, every effort should be made to minimize plant stresses such as drought, soil compaction, sun scald, lawn mower/weed trimmer injuries, etc. Because newly planted trees are under considerable stress, preventive sprays are advisable during the first 2-3 growing seasons after planting. Proper timing is important in order to have a lethal residue of insecticide on the bark to intercept newly-hatched larvae before they burrow into the tree. If you haven t already done so, now is the time to apply protectant sprays for all four species. Astro (permethrin) and Onyx (bifenthrin) are effective. Susceptible trees should be sprayed to runoff on the trunk and main scaffold limbs. A second application, three weeks after the first, provides extended protection. Degree Day Totals through May 25, 2008 Bardstown 1354 Bowling Green 1571 Covington 1175 Henderson 1400 Huntington WV 1290 Lexington 1264 London 1416 Louisville 1495 Mayfield 1359 Paducah 1583 Princeton 1579 Quicksand 1359 Somerset 1267 Degree Day Totals through June 27, 2007 Bardstown 1778 Bowling Green 1915 Covington 1635 Henderson 1797 Huntington WV 1690 Lexington 1676 London 1762 Louisville 1748 Mayfield 1746 Paducah 1937 Princeton 1991 Quicksand 1742 Somerset 1554 Office of the State Entomologist S-225 Ag Science Ctr N Lexington, KY State Entomologist John Obrycki, Ph.D Joe Collins: nursery inspections, newsletter, pest surveys & phytosanitary certificates Carl Harper: Slow-the-Spread gypsy moth trapping coordinator, nursery inspections, web design & phytosanitary certificates Katie Kittrell: nursery inspections- Western KY Janet Lensing, PhD: nursery inspections, State Survey Coordinator Phone: (859) Fax: (859) Princeton Phone: (270) ext joe.collins@uky.edu carl.harper@uky.edu katie.kittrell@uky.edu janet.lensing@uky.edu