Volume VI1, Issue 4 OFFICE OF STATE ENTOMOLOGIST July 2003 Pests susceptible to control-based on degree day forecasts ( )=Degree day ranges

• Taxus mealybug (1800-2100) • Black vine weevil (500-2100) • Euonymus scale (900-2100) • European elm scale (900-1200) • Fall webworm (1800-2100) • Japanese beetle (900-1200) • Leafcrumpler (1800-2100) Columbine leaf miner damage Eastern shoot borer larva in tip of pine Pine tube injury • Lecanium scale (900-1200) • Locust borer (1800-2100) apply final spray • Peach tree borer (1800-2100) • Pine needle scale (1600-1700) • Round headed apple tree borer (500-1700) apply final spray • San Jose scale (500-2900) re- Locust borer Pine tube moth larva Fourlined plant bug Hemlock scale peat applications because of overlapping generations Left: Spruce bud • Scurfy scale (1300-1500) scale • Spruce bud scale (1500-2100) Right: White marked tussock • Two-spotted spider mite (900-2100) moth • White marked tussock moth (1800- 2100) • Willow aphid (1600-2900) • Yellow-necked caterpillar Elongate Hemlock hemlock scale, Nuculaspis wingless, and are enclosed (1600-2200) tsugae (Marlatt), and the in an elongate, parallel- Scale hemlock woolly adelgid, sided cover that is light yel- US Forest Service Pub NA-PR-01-02 Seasonal Appearance of Orna- Pg 2 Adelges tsugae Annand. low to brown, translucent, mental Pests The elongate hemlock scale, Mixed infestations of scales and about 2mm long. The Pine Shoot Borers Pg 3 Fiorinia externa Ferris, native and adelgids can greatly male cover is elongate, Dogwood Anthracnose Present Pg 3 to Japan, is a pest of eastern hasten hemlock decline. white, and about 1.5mm in some Landscapes hemlock, Tsuga canadensis, Hosts: Elongate hemlock long. Adult males are light Early Case of Rust on Ky Blue- Pg 4 and Carolina hemlock, T. scale is known to develop brown, about 1.5mm long, grass caroliniana , in the Eastern and reproduce on 43 spe- have legs and wings, but are United States. It has been feeble-flying . Crawl- Leafminer Flies Pg 4 cies, representing 7 genera found in the District of Co- of native and exotic coni- ers are legged first-stage Wet Spring Favors Diseases of Pg 5 lumbia and in nine states from nymphs that hatch from Annuals & Perennials fers, including 14 species Virginia to southern New that are native to the United translucent eggs within the Pine Tube Moth Pg 5 England and west to . F. States. Spruce and fir tend female cover. Crawlers are 4-lined Plant Bugs Spot Mint Pg 6 externa attacks the lower sur- to be even more susceptible soft bodied, lemon-colored, face of the hemlock needle, than hemlock, although it and about 0.1mm long. Sec- Brown Patch Activity in Pg 6 where it removes fluids from ond-stage nymphs are en- Turfgrasses has not yet spread into the the mesophyll cells through natural ranges of these other closed in an oval, amber- White Pine Tip Burn Pg 7 piercing and sucking mouth- native conifers. colored cover, and are soft

Bagworms Have Hatched Pg 7 parts. Elongate hemlock scale bodied, sedentary, and vary sometimes occurs with two Description: Adult females in size from 0.1mm to Hemlock Looper Pg 7 other exotic pests - a circular are soft-bodied, legless, 1.0mm. Degree Day Accumulations Pg 8 PAGE 2 INSPECTOR FINDINGS VOLUME VI1, ISSUE 4

Hemlock Scale con’t eggs within her cover. When crawlers healthy condition will discourage the hatch, they exit through a small open- buildup of scale populations. For exam- Life History: The elongate hemlock ing at the posterior end of the cover. ple, hemlock have shallow roots and scale completes two generations each Elongate hemlock scale usually over- are consequently susceptible to year in the Southern and Mid-Atlantic winters, either as an egg or as an in- drought, so ornamental trees should be States, but usually only one in the seminated adult female. watered during dry periods. However,

Northeast. Its life stages are Damage to Hemlock: applications of nitrogen fertilizer and broadly overlapping every- Scale populations build broad-spectrum insecticides can exac- where, so crawlers can be slowly on healthy trees, erbate the pest problem. Nitrogen en- found throughout the spring but much more quickly hances the survival, development rate, and summer. Crawlers are the on stressed ones. Feed- and fecundity of F.externa, which re- only stage capable of dispers- ing by elongate hem- sults in higher scale densities on fertil- ing and establishing new in- lock scale causes foli- ized trees than on untreated ones. Also, festations. Dispersal between Close-up view of hemlock scale age to turn yellow and inadequate pesticide application can trees is primarily by wind and drop prematurely. Die- cause resurgence in scale populations birds. Females have three back of major limbs, which progresses by eliminating natural enemies. The stages of development after the egg, from the bottom of the tree upwards, aphelinid parasitoid, Aspidiotiphagus while males have five. Within a day or usually occurs after scale density citrinus Craw, consistently kills more two after hatching, crawlers of both reaches about 10 individuals per nee- than 90 percent of each generation of sexes settle beneath the thin waxy cuti- dle. Trees often die within the next 10 elongate hemlock scale in Japan. In the cle on the lower surface of the youngest years, but some survive longer in a se- northeastern United States rates of hemlock needles and begin to feed. The verely weakened condition with only a parasitization are inconsistent (5-96 first-stage nymph for both sexes se- sparse amount of foliage at the very top percent) because the life cycles of A. cretes a cover around itself as it grows. of the crown. These weakened trees are citrinus and F. externa are not synchro- It then molts into a second feeding unsightly and have little chance for re- nized. Two coccinellid beetles, the stage, continues to grow and add to its covery. They often fall victim to secon- twice-stabbed ladybird beetle, Chilo- cover. The second-stage female then dary pests, such as hemlock borer and corus stigma (Say), and Microweisea molts into the adult feeding stage. The Armillaria root diease, and are readily misella (LeConte), also attack F. ex- second-stage male molts into a non- broken and thrown by wind. Control: terna in North America, but not fre- feeding prepupa and spins a cocoon, Outbreaks of elongate hemlock scale quently enough to control scale popula- where it pupates before it emerges as often intensify following infestations of tions. Nevertheless, when broad spec- an adult. The adult male mates with the hemlock woolly adelgid, drought, or trum or poorly applied pesticides elimi- female and dies soon thereafter without other stresses that have weakened the nate these enemies, scale populations feeding. The adult female lays about 20 trees. Therefore, maintaining trees in often rebound dramatically.

Seasonal Appearance of Ornamental Pests and Normal Time Frame to Apply Control Measures (for the month of July) From the University of Tennessee Agricultural Extension Service PB 1589, Frank Hale, University of Tennessee

Hosts Pests Pine Pine tube moth, pine Maple cottony maple scale July (early) webworm, bagworms Oak kermes scale, obscure Arborvitae Fletcher scale, bag- Silver maple cottony maple scale, scale worms bagworms Pine pine tortoise scale, Elm elm leaf beetle Spruce pine needle scale Pales, northern pine Euonymus euonymus scale, bag- Walnut walnut caterpillar and white pine wee- worms Yew (taxus) black vine weevil, vil adults Flw’r fruit trees San Jose scale, bag- Fletcher scale Yew (taxus) black vine weevil,

worms July (mid) mealybugs, Fletcher Hemlock hemlock scale, pine scale Barberry barberry webworms needle scale, bag- Bittersweet euonymus scale July (late) worms Euonymus euonymus scale, Hemlock hemlock looper Honeylocust mimosa webworm winged euonymus Honeylocust mimosa webworm Linden cottony maple scale, scale Juniper juniper tip midge bagworms Flw’r fruit trees San Jose scale Oak oak skeletonizers Oak flatheaded apple tree Honeylocust mimosa webworm Yew (taxus) black vine weevil borer, bagworms VOLUME VI1, ISSUE 4 INSPECTOR FINDINGS PAGE 3 Pine Shoot Borers lier. Such injury may be confused with the shoot behind a needle fascicle and This article is from Johnson & Lyon’s book that of the white pine weevil. develops through five instars within the “Insects That Feed on Trees and Shrubs” 2nd As the larva develops, it cuts into the shoot over a period of 42-55 days. The edition. Control recommendation from Ohio wood at the base of the burrow but larva is dirty white and has a dark head. State Christmas Tree Fact Sheet by Dave Shetlar leaves the bark intact. The weakened It can be as long as 13 mm. When fully shoot droops or breaks-this is often the developed, the larva chews an exit hole Editor’s note: this pest is different from the first symptom of attack by the pest. and drops to the ground. A light brown Federally regulated pest, pine shoot beetle The loss of needles and the reduced pupa is then formed in a loosely woven Nine or more species of tip and shoot size of the terminal leader are quite im- cocoon either in the top few inches of portant to the Christmas tree grower. A the soil or in debris. attack pine. The eastern pine shoot borer, Eucosma gloriola leader size of 20-35 cm is desirable. Though this pest can be locally severe, Heinrich, is a native of North America. After an eastern pine shoot borer at- little work has been done to develop It may be found throughout the natural tacks its host, only 7.5 to 10 cm stub control products or timing schemes. may remain. range of white pine, including eastern Option 1: Biological Control - Con- Canada south to and Vir- The shoot borer overwinters as a pupa serve Native Parasites - Apparently, a ginia and west to Minnesota and Mani- in the soil. Adults emerge any time parasitic wasp kills a good number of toba. The major host plants are 4 to 10 from late April to early June, depend- the eastern pine shoot borer larvae. In- year old white, Scotch and red . ing on the geographic location. Moth secticide sprays applied in Christmas Other hosts include the Austrian, jack, emergence in some areas seems to oc- tree plantations for control of other in- mugho, and pitch pines and, on occa- cur shortly after the Scotch pine buds sects probably reduce this parasite's sion, Douglas-fir and other conifers. burst open. The adult moth has a wing- effectiveness. Therefore, apply insecti-

Damage to the plant is caused by larval span of 14-15 mm. During the day, the cides only when necessary. Option 2: feeding and tunneling in the pith of rests on the shaded inner foliage Chemical Control - Insecticide Sprays - new shoots. Either the leader or or lat- of the pine. Eggs are laid on twigs or Sprays using registered insecticides eral shoots are attacked, but more often on needle sheaths and can be found sin- should be applied in early May when the latter. Foliage on mined shoots gly or in twos and threes. These eggs the eggs are hatching and the larvae are fades and turns red in the summer, al- are round, flattened, pale yellow, .5 entering new shoots. Systemic insecti- though smaller twigs may redden ear- mm in diameter, and hatch in 10-15 cides applied in mid-May will kill the days. The newly hatched larva enters young larvae within the shoots.

Dogwood Anthracnose scape trees and also on some fruit mote rapid foliage drying early in the crops, they are not all caused by the day. Present in Some Landscapes same fungus. Each host plant has its John Hartman, Extension Plant Pathologist, own anthracnose fungus, so, for exam- ---Prune out and destroy dead wood and University of Kentucky ple, don't assume that anthracnose of leaves as they occur, and prune trunk Dogwood anthracnose, caused by the sycamore or strawberry is a threat to sprouts in the fall. fungus Discula destructiva, is appear- nearby dogwoods. ing with greater frequency this ---Protect trees from drought by watering spring in many Kentucky Kentucky growers at least once a week during dry periods. flowering dogwoods and gardeners should Do not use overhead sprinklers for water- (Cornus ). Cool, know how to grow ing; wet foliage favors infection. wet spring weather may and maintain healthy be contributing to the dogwoods. Good ---Maintain a 2-4 inch layer of mulch greater disease levels growing practices are over the root zone of the tree (but not observed this year. Dog- important in prevent- against the trunk) to help maintain soil wood anthracnose causes ing loss of dogwoods moisture and to protect trees from lawn- leaf spots, leaf blight, from anthracnose. mower injury. and lower branch die- Consider the follow- back and is most com- ing: ---Diagnose and treat insect and disease monly observed in for- problems appropriately. ested regions where na- ---Do not transplant tive understory dogwood trees are dogwood trees from the wild. Purchase ---Plant disease resistant dogwoods such threatened. This spring, anthracnose is healthy trees from a reputable nursery. as C. florida 'Appalachian Spring' or ori- also present in landscape trees, espe- ental dogwoodsAdult (Cornus lacebug kousa ) for high cially those growing in shaded loca- ---Anthracnose is favored by a moist risk sites such as those with heavy shade tions. Although anthracnose diseases environment. Select a planting site and nearby diseased trees. are common this year on other land- with a sunny eastern exposure to pro- PAGE 4 INSPECTOR FINDINGS VOLUME VI1, ISSUE 4

Surprisingly Severe, Early Case of Rust on Ky Bluegrass given the kind of spring we've had, but Paul Vincelli, Extension Plant Pathologist, University of Kentucky summer is just beginning.) For these outbreaks of rust, I do recommend Normally rusts on foliage of cool- leaf. Since rust fungi are obligate para- maintaining adequate soil moisture season grasses occur in late summer sites (meaning they can only grow on through the summer. This will help and autumn in Kentucky. Early sum- live host tissue), they cease growing in maintain slow growth, giving the grass mer outbreaks, like the severe case that lawn clippings. Thus, maintaining ac- some chance against the disease; also, was diagnosed on Kentucky bluegrass tive turf growth through cultural prac- plants affected by rust need more water in the Bluegrass region tices combined than last week, are unusual. with regular mow- unaffected plants just to avoid wilting. This early and severe ing is usually suf- "Spoon-feeding" nitrogen by applying outbreak may indicate a ficient to manage 1/8 to 1/10 lb N/1000 sq ft every 10-14 rather high potential for the disease under days will also help the sward survive disease development Kentucky condi- until the end of August, when high later in the year, since tions. rates of soluble nitrogen will promote inoculum levels have Unfortunately, this recovery. built up already in is not a good time For high-maintenance swards where some sites. of the year to fer- managers wish to treat with fungicides, Foliar rust diseases on tilize cool-season Heritage and the DMI fungicides propi- cool-season grasses in grasses. The addi- conazole (Banner MAXX and related Kentucky are favored by factors that tion of moderate to high rates of nitro- products) and triadimefon (Bayleton slow the growth of the grass, such as gen will enhance summer diseases like and related products) are the most ef- low nitrogen or low soil moisture summer patch and may also weaken the fective, safe choices. Recognize that a status. Normally, in actively growing grass's resistance to temporary drought fungicide spray can only protect new turf, rust infections are mowed off be- stress. (I know it's hard to imagine growth from infection; it cannot cause fore they cause much damage to the such a thing as temporary drought, disease leaves to become healthy again.

Leafminer Flies blotch mines as they feed. Mature mag- ticulturist into an ongoing spray pro- gots crawl from the mine to pupate on a gram. James Baker & S. Bambara, Extension Entomologists, NC State University leaf nearby. There are several genera- For the leafminer flies of evergreen tions per year. Infested leaves look as hollies, timing of pesticide application Leafminers in the family Agromyzidae though they have been blighted by a is important for optimum suppression. are small and usually dark flies. Some disease and the appearance of the host If the leafminers appear to be getting species have yellow markings. These plant is ruined. out of hand, one strategy is to realize flies are fairly similar and are more eas- The holly leafminers make typical ser- that the adults emerge in the spring to ily recognized by their host plant and pentine mines in the leaves of hollies. lay eggs in new leaves. In early April the damage to the host plant than by the The maggots pupate at the large end of place several infested leaves in a dry insect itself. Some leafminer maggots the tunnel and the adult fly emerges plastic bag in the shade. When the make serpentine tunnels that increase in from a hole in the pupal skin and the small, dark flies are found in the bag, size as the maggots grow. Other species upper leaf surface. Each species of that is the perfect time to spray. Be- make blotch mines or mines that are holly has its own leafminer species. cause leafminers are usually protected intermediate. This note does not pertain Deciduous holly leafminers have sev- by the leaf surface on top and bottom, to the boxwood leafminer, a gall- eral generations per year, whereas the systemic pesticides (pesticides ab- forming fly belonging to a different leafminers of evergreen hollies have sorbed and translocated by the plant) family. only one generation per year. Leaf- should be given consideration for con- Leafminer flies are pests of columbine, miner maggots have parasites that often trol. The foliage of susceptible plants butterfly weed, chrysanthemum, ciner- decimate the leafminer population. should be observed for early signs of an aria, delphinium, gerbera daisy, holly, Control infestation. When tunnels are first no- impatiens, mist flower, verbena, water ticed, the following pesticides are rec- lily and other ornamentals. Because leafminers are plagued by ommended for control on annual and parasites, it may be better to rely on perennial flowers and hollies. Read and The larkspur leafminer causes blotch parasites to suppress leafminers than to mines in the leaves of delphinium, lark- follow labeling directions and warnings apply pesticides that might eliminate carefully! spur and aconite. Females lay their the parasites and force the amateur hor- eggs in the leaf and the maggots make VOLUME VI1, ISSUE 4 INSPECTOR FINDINGS PAGE 5

Wet Spring Weather Has Favored Many Diseases of structures, which can be seen with a hand Annuals and Perennials lens. Septoria affects carnation, chrysan- John Hartman, Extension Plant Pathologist, University of Kentucky themum, daisy, marigold, peony, phlox and other hosts. Cool wet weather, cloudy skies and sum, bleeding-heart, bluebells, butter- high humidity during the past month or cup, candytuft, corydalis, evening Bacterial Blights. Wet weather has fa- so have favored several diseases of per- primrose, forget-me-not, ornamental vored dissemination of several of the ennial ornamental plants in the garden. tobacco (the species causing tobacco bacterial diseases, particularly those The following are some of the diseases blue mold), ornamental raspberry, which do well in cool weather. Species that have been observed recently in the phlox, poppy, rocket, rose, salvia, snap- such as Pseudomonas often cause shoot plant disease diagnostic laboratory or in dragon, stock, sweet-pea, and veronica. blights in cool, wet weather and some the field, or that might be observed in -Basidiophora causes downy mildew of Xanthomonas species cause leaf spots. Kentucky during this time. asters and goldenrod. Although there has not been much fire blight this year, species of Erwinia may Downy Mildew. Downy mildew dis- Botrytis Blight. Caused by the fungus be causing soft rot diseases in some in- eases are caused by obligate parasite Botrytis cinerea, botrytis blight is also stances. Bacterial blights of rose-of- oomycete fungi that form mycelium in called gray mold. The fungus generally Sharon (Pseudomonas) and of canna plants and sporulate in great numbers is weakly parasitic, growing on senes- (Xanthomonas) have been observed. through stomata. The sporangia make cent parts of many different host plants. Carnation, chrysanthemum, delphinium, white, gray, or violet patches usually In wet and humid weather, the fungus gladiolus, nasturtium, sunflower, and on the undersides of leaves. Downy decays affected plant parts and pro- many other ornamentals can also be hosts mildew diseases occur on many differ- duces powdery gray to tan sporulation to Pseudomonas. Xanthomonas (causing ent kinds of plants. For the most part, on rotted tissues. This spring, Botrytis leaf spots and blights) and Erwinia each disease is caused by its own spe- gray mold has been observed on bego- (causing soft rots) have very wide host cies of downy mildew fungus. Downy nia, rose, peony, periwinkle and other ranges among ornamentals. mildews are favored by cool, overcast, hosts. This fungus has a very wide host and moist weather - conditions which range including such ornamentals as Powdery mildew. Powdery mildew is a were in abundance this spring. In addi- anemone, aster, begonia, calendula, threat all season long when there is high tion, this disease is favored by avail- carnation, chrysanthemum, dahlia, ge- humidity. Almost all perennial and an- ability of soft, succulent host tissues. ranium, lily, marigold, peony, prim- nual ornamentals, too numerous to list Favorable weather conditions also pro- rose, rhododendron, rose, snapdragon, here, are moted succulent growth this spring. sunflower, zinnia and many others. susceptible to one or another powdery mildew. Along with wet weather this Downy mildew of foxglove and core- Fungal Leaf Spots. Black spot is well- opsis, caused by species of Plasmopara spring, long periods of high humidity developed on susceptible roses. Cerco- favored powdery mildew of many garden and of Potentilla, caused by species of spora and Septoria leaf spots have also Peronospora have been observed. plants. been observed. The fungus Cercospora Some other downy mildew hosts in- is an imperfect fungus and it generally Because of disease-favorable weather, clude: causes somewhat circular spots with Kentucky gardeners and County Exten- -Different species of Plasmopara cause tan centers. Different species of Cerco- sion Agents may be seeing a more than downy mildew of anemone, Centauria, spora cause leaf spots that affect calla usual accumulation of spots, blights, and fleabane, geranium, hepatica, Impa- lily, calendula, columbine, geranium, mildews this spring. In many cases, tiens, Rudbeckia, and sunflower. hollyhock, and rose. Septoria species there is little that can be done to save al- -The downy mildew fungus Bremia cause, spots, blotches, and blights. In ready affected plants and in most cases, also occurs on Centaurea. the diseased tissue, the Septoria fungus these diseases will slow down as weather -Species of the fungus Peronospora produces pycnidia, tiny black fruiting becomes warmer and drier. cause downy mildews of allium, alys-

Pine Tube Moth Distribution and Hosts: Pine tube Identification: These small, slender Rayanne Lehman, PA Dept of Ag, Bureau of moth occurs in eastern North America, moths have wingspans of 14 mm. Two Plant Industry from Canada south to Florida and west off-white oblique lines are found on the to Wisconsin, throughout the range of reddish-orange forewings. When the This minor pest of eastern white pine is its principal host, eastern white pine. A moth is at rest, these wings conceal the best recognized by the symptoms it related species, the tube moth smoky-colored hindwings and gray to tan produces (Fig. 1) rather than by the ap- ( tabulana), causes similar body. This coloration effec-tively camou- pearance of the insect itself. Its damage symptoms on jack, lodgepole, and flages the moths when they rest near un- is purely aesthetic and control is rarely whitebark pines in the Rocky Mountain opened buds. The pale green larvae warranted. states and the Canadian provinces of reach 12 mm at maturity. Identification Distribution and Hosts: Pine tube Alberta, Manitoba, and Saskatchewan. of pine tube moth is generally accom- moth occurs in eastern North America, PAGE 6 INSPECTOR FINDINGS VOLUME VI1, ISSUE 4 Pine Tube Moth con’t in July. 1993). When feeding and development

Eggs are deposited on the needles. is completed, lar-vae pupate inside the plished through symptoms, rather than needle tubes. Upon emergence, larvae spin silk and examination of larvae or adults. tie 5-20 needles together to form a Damage: Pine tube moth is a minor Life History: There are two genera- tube. The caterpillars lie within this pest of eastern white pine. The damage tions of pine tube moth each year in silk-lined tube, moving to the open end caused is purely aesthetic and may . Adults emerge from to feed on needle tips. When the tube even go unnoticed until the empty overwintering pupae in early- to mid- walls (needles) have been eaten down tubes turn brown in late summer. April, about the time spruce spider mite to 1 inch, partially developed larvae Rarely, specimen white pines in a land- eggs hatch (personal observation). This will abandon their tubes and begin con- scape may appear ragged due to the is several weeks earlier than the May structing new ones. First and second action of this pest. Control is generally emer-gence reported in the literature generation larvae are active from 91- not warranted and would be extremely (Johnson and Lyon 1988). The second 246 and 1151-1514 growing degree difficult since the larvae are protected 0 generation adults are reported to appear days (base 50 F), respectively (Clark inside the needle tubes.

Fourlined Plant Bugs Spot the insects near maturity. In addition to spots, the plant's reaction to enzymes the feeding damage, white cast skins injected into the leaf by the insect, can Mint and tarry waste specks may be seen range from white to almost black de- Lee Townsend, Extension Entomologist, Univ. of Kentucky when nymphs have been present for a pending on the host. Feeding by large long time. The adult and nymphal numbers of plant bugs can produce Plant bugs and lacebugs use their suck- stages of the same species can look large brown blotches and/or leaf distor- ing mouthparts to feed on plant sap. very different, which can confuse iden- tion.

Damage ranges from many small white tification. Females cut slits into the host plant and spots on the leaves to distortion or de- Fourlined plant bugs feed on mint, as lay six to eight eggs inside. There is struction of plant tissue, depending on well as many herbaceous and woody one generation a year. It occurs during the pest and host plant. Some feed on ornamentals including currant, rose, a six-week period from late May many different types of plants while forsythia, sumac, and viburnum. The through June. others feed only on a narrow range or nymphs are bright red or yellow, adults Control is difficult because the adults single species. is yellow to yellowgreen. Both stages fly readily when disturbed. Both the Adults fly readily and are often gone have four distinct black lines running nymphs and wingless adults drop to the before symptoms appear. Their injury the length of the body, hence their ground if the foliage is disturbed. In- is often light to moderate and widely name. secticidal Soap can be used for control distributed. In contrast, the immature or This plant bug can be very destructive, but requires direct contact with the in- nymphal stages are wingless and can especially to herbs and mint. It feeds sect. A plant covering may be used to move only by walking. Injury builds first on the upper, tender foliage leav- exclude these insects from herbs. slowly but can become very intense as ing distinct redbrown spots. These

Brown Patch Activity in bluegrass in Central Kentucky. I have mornings, the mycelium of the fungus never before observed significant levels often appears as a sparse, very light tan Turfgrasses of brown patch in this well-adapted webbing in the lower canopy. This can Paul Vincelli, Extension Plant Pathologist, Univ. cultivar for Kentucky. This just shows be best seen with a hand lens. In some of Kentucky how favorable the past 7-10 days have cases, mycelium can be quite dense, been for brown patch activity. cottony, and fluffy, and grow all over Brown patch disease was very active last week in a number of grasses. Given On all grasses, affected patches are of- the leaf blades. In this state, it can look the forecast for hot, humid weather ten somewhat circular and can range quite a bit like Pythium cottony blight. with the possibility of thunderstorms from several inches to two or more Since different fungicides are used towards the end of the week, brown feet in size. On tall fescue and Ken- against Pythium cottony blight and patch pressure will likely increase on tucky bluegrass, leaves exhibit Rhizoctonia brown patch, knowing the cool-season turfgrasses. Perennial rye- tan, irregular lesions with a thin, brown identity of the disease can be quite im- grass is probably the most susceptible border. On creeping bentgrass and per- portant from a management standpoint. host; creeping bentgrass and tall fescue ennial ryegrass, a ring of olive-green Laboratory diagnosis is one option; an- are both relatively susceptible. Surpris- leaf blades appears on the outside mar- other is the use of Alert Plant Disease ingly, we also saw a significant case of gin of the patch; these blighted leaf Detection Kits from Neogen, which brown patch on 'Midnight' Kentucky blades dry to a tan color. On humid have worked well in my evaluations (www.neogen.com/disease.htm). VOLUME VI1, ISSUE 4 INSPECTOR FINDINGS PAGE 7 White Pine - Tip Burn on needle cast, are much more common on blight," but we do not have air pollu- Scots and Austrian pines, although they tion data to support this diagnosis, nor Emerging Needles can occur on white pine. These dis- has recent weather been conducive to by Julie Beale, Plant Diagnostician, Univ. of Ky. eases both produce a spot or band on episodes of high ozone. Other environ- Over the past two or three weeks, the the needle, followed by needle brown- mental factors may also be contributing Plant Disease Diagnostic Laboratories, ing and drop. However, the infections to the symptoms; we suspect that the both in Lexington and Princeton have of both of these fungal diseases are oc- stunting of needles in some trees may received a number of white pine sam- curring now (spring and early summer) relate to cool, wet spring conditions in ples showing a distinct tip burn on the on current-year needles, and the symp- general. Individual trees will differ in new needles. Some of these trees also toms will not be visible until late sum- their susceptibility to environmental show stunting of the new needles in mer or fall; often they are not noticed stresses, as well as air pollutants, so it addition to the tip burn, but others have until the following spring. We do not is not that unusual for certain trees to normal, even vigorous, needle and see the Sphaeropsis tip blight disease have no symptoms. Affected trees may shoot growth. In affected trees, symp- which blights the entire growing shoot not be at their most attractive this year, toms are reported to occur all over the on white pine. Obviously, the symp- but the overall health of the tree should tom patterns of these diseases differ not be impacted long-term. tree not one-sided as we might see with a salt injury. Also affected trees can be from this recent white pine problem, Also consider the differences between adjacent to white pines with no symp- and of course, infectious diseases are these symptoms and those of white toms. confirmed by finding the microbial pine decline that we so often see in pathogen on affected needles, not only Kentucky landscapes. This abiotic dis- Close examination of the needles re- looking at the symptoms. veals an interesting pattern: while the order starts out with a general yellow- basal portion of the needle is green, A number of possible causes for the ing and thinning of the entire canopy of there is a band of dark, reddish tissue symptoms exist. The most likely sce- a tree over a period of several years. around the mid-point of the needle and nario is that new needles were injured Tip burn can occur on old and new from this band to the tip, the needle is by late frosts as they were expanding needles as well as premature drop of brown (or reddish-brown) and desic- this spring. Temperatures reached the needles from the previous season, re- cated. Under the dissecting micro- low 30's on the morning of April 23rd duction in annual shoot growth, shriv- scope, we see the "band" on the needle throughout the region, and this may eling of the bark and eventual decline is a narrow area of sunken tissue that have killed a band of the youngest and death. This disorder is related to constricts the needle. Since many nee- (basal) needle tissue. Once this band of our soil conditions, which are generally dle blight or needle cast diseases will tissue was damaged, water supply to not appropriate for eastern white pine. produce a band on the needle at the the tip was cut off, eventually resulting Dr. Bill Fountain, Extension Horticul- point of infection, it is helpful to con- in the death of the needle beyond that turist, reminds us that white pines trast this symptom with those of our point. Needles expand from the base, evolved in areas with deep, well- common needle diseases. First, most so healthy needle tissue continued to drained loamy or sandy soils with a low expand after the injury occurred. pH (below 6.5). Our higher pH clay diseases affect trees in a scattered or random pattern, i.e., some needles are Air pollutants, including ozone and sul- soils and compacted landscape sites affected, and others on the same tree fur dioxide, are also reported in some hardly provide good growing condi- are not. In addition, the two major nee- sources to produce this symptom, tions for these trees, hence their ten- dle diseases we see in this area, brown called "semi-mature tissue needle dency to decline after twelve to fifteen spot needle blight and Naemacyclus years in our area.

Bagworms Have Hatched pointed upward. The bag is gradually material after becoming wind-borne on enlarged as the larva grows. Older lar- silken strands. Mike Potter, Extension Entomologist, Univ of Ky vae strip evergreens of their needles and Overwintering eggs can be destroyed by Bagworm eggs have hatched and the consume whole leaves of susceptible hand-picking old bags during the winter young larvae are at their most vulner- hardwood species, leaving only the lar- or early spring. Since the window of able stage for treatment. This caterpillar ger veins. opportunity for this approach has is a serious defoliator of many different Control- The best time to control bag- passed, insecticides are now the only kinds of landscape and nursery plants. worms is while the larvae are small. effective means of control. For home- They are especially damaging to ever- Carefully inspect susceptible landscape owners, Sevin, Bayer Advanced Lawn& greens such as juniper, arborvitae, plants (especially evergreens) for last Garden Multi-Insect Killer, Spectracide spruce, pine and cedar. Bagworms over- year's bags. Preventive treatment is of- Triazicide, or Bacillus thuringiensis winter as eggs within spindle-shaped ten justified on plants that were heavily (BT) work well. For nursery and land- bags made of silk and bits of plant mate- infested with bagworms the previous scape professionals, other effective rial. Young larvae emerge and immedi- year. Small bagworms may also dis- products include: Astro, Mavrik, Scimi- ately begin feeding on the upper side of perse to previously non-infested plant tar, Suspend, Talstar and Tempo. leaves, camouflaged within a tiny bag Hemlock Looper pleted. High populations can remove Degree Day Totals through June 26, 2003 Bardstown—1343 Pest Alert, US Forest Service , NA-PR-05-92 nearly all the new and old needles in a single season. Bowling Green—1509 Covington—1140 The hemlock looper Lambdina fiscel- This looper is a wasteful feeder, often Henderson—1404 laria is a defoliating insect native to nipping only a small part of a needle Huntington WV—1294 North America. It occurs in the eastern before moving to another. As these Lexington—1272 United States from to needles dry out they change color and London—1298 and west to Wisconsin. The larvae can along with the exposed twigs, result in Louisville—1350 be extremely destructive to hemlock, a reddish-brown color characteristic of Mayfield—1374 balsam fir, and white spruce. During an an infested stand. Often a mat of Paducah—1506 outbreak it will also feed on many other clipped needles collects under the tree. Princeton—1508 species including: larch, red and black Quicksand—1378 Another looper, L. athasaria may cause spruce, cedar, jack pine, paper and yel- Somerset—1418 similar damage on hemlock. It closely low birch, basswood, maple, elm, and resembles L. fiscellaria in all of its life wild cherry. Hemlocks may die after Degree Day Totals through March 26, stages making identification between one year of severe defoliation, fir in 2002 the two species very difficult. L. one or two years. Bardstown - 1475 athasaria overwinters in the pupal Bowling Green - 1557 Hemlock looper moths are tan to gray- stage. Damage by the larvae is later in Covington - 1196 ish-brown in color and have a wing- the summer. Henderson - 1535 span of approximately 1.25 inches. The Huntington WV - 1410 female lays her tiny eggs on a variety Lexington - 1377 of substrate throughout the forest from London - 1392 August to October. After overwintering Louisville - 1425 in this stage the eggs hatch from late Mayfield - 1487 May to mid-June. The larvae feed ini- Paducah - 1633 tially on new foliage but quickly move Princeton - 1750 to old foliage. They return to the new Quicksand - 1496 foliage only when the old foliage is de- Somerset - 1453

OFFICE OF STATE ENTOMOLOGIST

S-225 Agricultural Science Center - North Lexington, Kentucky 40546-0091

We’re on the web! www.uky.edu/Agriculture/ NurseryInspection

Interim State Entomologist— Fred Knapp, Ph.D Nursery Inspectors—Joe Collins & Carl Harper Phone: (859) 257-5838 Fax: (859) 323-1120 Email: [email protected] [email protected]