September 2009 Volume XIII, Issue V1

Inside this issue:

Bacterial Leaf Scorch 2

High Activity Time For Lone Star Ticks

3

Giant Beetles of Summer 3

Caterpillars That Pack A Punch

4

Meeting The Threat of Hemlock Woolly Adelgid

4

Brown Soft Scale 6

Redbay Ambrosia Beetle 7

Emerald Ash Borer Update 8

Inspector Findings in Kentucky

Office of the State Entomologist

www.KyStateEnt.org

Picture key: 1: Hemlock Woolly Adelgid (photo from Dr. Tom Coleman, US Forest

Service 2: Lone Star Tick (photo from www.insectimages.org)

3: brown soft scale 4: fall webworm (photo from www.insectimages.org)

5 & 6: adult redbay ambrosia beetle 7: string of compacted ambrosia beetle sawdust 8) stained sapwood of redbay caused by the fungus introduced by the redbay ambrosia beetle (Pictures 5,6,7,8 from Albert Mayfield III FL div of Forestry and MC Thomas, FDACS/DPI)

Page 2 Volume XIII, Issue V1

Bacterial Leaf Scorch Symptoms are Appearing John Hartman, Extension Plant Pathologist, University of Kentucky

Bacterial leaf scorch, caused by Xylella fas-tidiosa, has been con-firmed in the U.K. Plant Disease Diagnostic Labo-ratory on pin oak and sycamore samples in re-cent weeks (Figures 1 & 2). Symptoms of this dis-ease should be appear-ing now on several spe-cies of landscape trees throughout Kentucky. Look for trees showing premature yellow or brown color from a dis-tance (Figure 3). Leaves of infected trees typically show marginal necrosis (scorch) late in the sum-mer followed by prema-ture defoliation (Figures 4 & 5). Infected trees re-foliate normally in spring and the process of late summer scorch and pre-mature defoliation is re-peated. Moist weather this season has reduced tree water stress which, compared to most years, has probably delayed appearance of symptoms in infected trees. Never-theless, bacterial leaf scorch symptoms are definitely visible on many trees now. The disease begins on one or a few branches and over sev-eral years gradually spreads throughout the tree (Figure 6). After many years, dead twigs, then dead branches and limbs begin to appear in the tree (Figure 7) and the condition continues to worsen over the years until the tree needs to be removed. Bacterial leaf scorch is a very problem-

atic plant disease in Ken-tucky.

Bacterial leaf scorch af-fects many Kentucky landscape trees including oaks (pin, red, scarlet, shingle, and white) ma-ples (Norway, red, silver, and sugar), planes (American sycamore and London plane) sweet-gum, hackberry, elm and mulberry. Oaks are widely planted in Ken-tucky and the disease is most common in them. Bacterial leaf scorch is not a curable disease, but it can be slowed some with basal root flare injec-tions of antibiotics applied in springtime.

Fig 1: symptoms of bacterial leaf scorch of pin oak; Fig 2: Sycamore with

bacterial leaf scorch symptoms

Fig 3: Bacterial leaf scorch infected pin oak flanked by two green, healthy

trees

Fig 4: Bacterial leaf scorch of English

oak

Fig 5: bacterial leaf scorch of shingle

oak

Fig 6: Red oak with bacterial leaf scorch. Note that branches in the middle show symp-toms while other branches are still

green and healthy.

Fig 7: Bacterial leaf scorch-infected pin oak with dead twigs and branches in the top of the

tree.

Page 3 Volume XIII, Issue V1

The lone star tick is our most troublesome species based upon its frequency of attack on humans and animals; this is the time of year when they are at their peak (Figure 1). Anyone accidentally moving thru clusters of tiny, hungry seed ticks can face a miserable few days. Female ticks lay hundreds to thousands of eggs in clusters on the ground. The masses of 6-legged larval (or seed) ticks that emerge from these eggs climb vegetation and wait with front legs extended to latch onto a passing human or animal. They will wander on the skin for a time (in some cases up to 24 hours) before attaching to feed. Barbed mouthparts are inserted into the skin and a cement is secreted to hold ticks in place while they engorge, a process that can take from 2 hours to 7 days; then they drop from the host. Ticks inject an anesthetic

material that makes the actual bite painless. However, the bite site may be red and painful for 1 to 2 weeks after the tick has fed.

Frequent, careful inspections are essential for those who are in situations that expose themselves to ticks. Here are some tips: 1) Look for movement of very small, freckle-like spots on clothing and skin – they may be seed ticks. The larger nymphs and adults are much easier to see. Wearing light clothing, especially pants, will make them easier to spot. 2) Avoid overgrown areas along trail edges or woods – ticks are more likely to occur there. 3) Use repellents or clothing treatments with permethrin when in areas where ticks are known to be active.

Ticks usually wander on people for some time before attaching. Regular inspections will help to catch them before this

occurs. Also, it appears that infected ticks must feed for 24 to 48 hours before disease transmission occurs. More information on the

lone star tick in Kentucky is available in www.ca.uky.edu/entomology/dept/entfacts.asp

High Activity Time for Lone Star Ticks Lee Townsend, Extension Entomologist, University of Kentucky

The eastern Hercules beetle (Dynastes tityus) has a large (2" to 2-1/2" long) greenish-gray to black body. Males have a large distinctive horn on the head and sometimes

are called rhinoceros beetles; females do not have the horn. The adults are attracted to lights dur-ing mid- to late summer and will eat overripe fruit.

Hercules beetle larvae are white grubs that feed on decaying plant mate-rial, especially logs, stumps, dead leaves, and rotten fruit. They may spend two years in this stage. The grubs are a food source for skunks, raccoons, and other mammals.

Giant Beetles of Summer—Hercules Beetles Lee Townsend, Extension Entomologist, University of Kentucky

Figure 1—Lone star ticks have late burst of activity

Below—Lone star tick larvae (seed ticks) are tiny brown spots on pant

leg (Logan Minter, University of KY photo)

Page 4 Volume XIII, Issue V1

Caterpillars are tasty morsels for predators so many species rely on camouflage to stay off the menu. Those that can protect themselves, sting-ing caterpillars for exam-ple, stay in plain sight and advertise with bright or distinctive markings. They are covered with sharp, brittle bristles that break off and stick in the skin like so many cactus spines. Unfortunately, that’s not all, the bristles are hollow and contain an irritating substance that produces a very unpleas-

ant skin reaction.

Saddlebacks (picture) are relatively common in Kentucky are among the most venomous species in North America. A full grown caterpillar is brownish red, about 1.25 inches long, and has sev-eral distinctive character-istics which include two fleshy horns studded with spines on each end, shorter armed bumps along both sides. The back carries a bright green "blanket" trimmed in white, with brown-to-purple central spot or

"saddle", also trimmed in white. Saddlebacks occur on many plants including apple, basswood, cherry, chestnut, dogwood, elm, maple, oak, plum, and even corn. They are most abundant at this time of year.

A brush with a saddle-back results in immediate pain followed by swelling and blistering if the spines are not removed. The irritation should be gone in 8 hours or less if the spines are removed. They can be stripped cel-lophane or adhesive duct tape. Wash the area with soap and water and apply an ice pack to relieve the

irritation. Contact a physi-cian immediately if the irritation does not subside of if other symptoms ap-pear.

More information on stinging caterpillars is available in www.ca.uky.edu/

entomology/entfacts/entfactpdf/ef003.pdf

Caterpillars that Pack a Punch Lee Townsend, Extension Entomologist, University of Kentucky

Saddleback caterpillar—top view

Note: Ohio has changed their hemlock regulations. Depending on which county your nursery re-sides, if you ship hem-locks to Ohio, you may be required to treat the hemlocks prior to ship-ment. If you have ques-tions, please call Joe Collins at 859-257-5838 or email joe.collins@uky.edu

The hemlock woolly adel-gid (HWA), a native of Asia, is a 1/32 inch long reddish purple insect that lives within its own pro-tective coating. White, woolly masses that shel-ter these sap-feeding in-sects are at the bases of hemlock needles along infested branches. The presence of these white

sacs, which resemble tiny cotton balls, indicate that a tree is infested.

HWA is a threat to east-ern hemlock forests, and eastern and Carolina hemlock of all sizes are susceptible. Kentucky has a significant hemlock component throughout its eastern forests, all of which could become in-fested. In addition, orna-mental plantings in urban settings are equally sus-ceptible. HWA feeding reduces new shoot growth, and causes gray-ish-green foliage, prema-ture needle drop, thinned crowns, branch tip die-back, and eventual tree death.

Control Options

Homeowners and private landowners have two

treatment options: 1) spray foliage with insecti-cidal soap or horticultural oil at the proper times during the HWA life cycle, or 2) use a systemic in-secticide that moves with the tree sap and is con-sumed by the adelgids as they feed.

Tree sprays

Several brands of insecti-cidal soaps and horticul-tural oils are available at garden centers or from retail stores that sell pes-ticides. These are contact insecticides that must thoroughly cover the in-sects to kill them so the foliage, twigs, and branches must be sprayed almost to runoff. Neither product leaves a toxic residue so several applications may be needed. The soaps and oils can be applied to small trees with pump-up garden sprayers but power sprayers are

needed to treat larger trees. If coverage is not thorough or trees are too tall for the equipment that is available, surviving HWA soon will reinfest the trees.

These applications will be most effective only during two treatment win-dows when stages of the HWA that do no have a protective covering are active. One is following egg hatch from March through April, the other is from September to Octo-ber. Read the product label carefully before pur-chasing and applying an insecticidal soap or horti-cultural oil. In some cases, there will be pre-cautions against spraying when temperatures are above or below certain limits, on windy days, or in late spring when the new growth is present on the tree and has not hardened to the dark shade of green.

Meeting the Threat of the Hemlock Woolly Adelgid Lee Townsend, Extension Entomologist, University of Kentucky

Page 5 Volume XIII, Issue V1

Insecticidal soaps and horticultural oils can be used in sensitive sites near houses, creeks, or ponds without risk to non-target organisms or the environment. Foliar sprays with other insecti-cides can be effective but some pose risks to the environment.

Systemic Treatments

Systemic insecticides containing the active in-gredient imidacloprid can be used as soil drenches or injections to control the HWA. Brand names in-clude Bayer Tree & Shrub Insect Control Concentrate or Merit In-secticide. Imidacloprid, which is very soluble in water, is taken up by tree roots and moved in the sap to sites where the adelgids are feeding. This approach eliminates the problem of spray cover-age, especially on trees that are too tall to treat using available equip-ment. This treatment should be applied during spring (mid-March to early June) and fall (mid-September to mid-November). The ground should not be frozen or waterlogged but the soil should be moist. Re-search indicates that the treatment requires at least 30 days to be taken up by the tree, but it can kill adelgids for about 24 months. Homeowners with infested hemlocks may consider soil treat-ments if HWA has been reported in their county. There is no preemptive treatment for the hemlock adelgid.

There are three methods

for applying the systemic insecticide:

Soil drenching. The ap-propriate amount of in-secticide, based on the product label, is diluted with water and applied evenly to the soil surface or into a series of small holes spaced evenly around the base of the tree at a distance of 6 to 12 inches. This is fol-lowed by an equal vol-ume of water to help move the insecticide down into the soil. Sur-face litter should be raked away prior to treatment to ensure good penetration. Soil should be moist at the time of treatment so the area may need to be watered in advance if it is dry.

Soil injection. (shown right) The insecticide solution is injected sev-eral inches beneath the moistened soil surface with a hand-powered Kioritz soil injector. This injector allows good placement of the insecti-cide that allows for effi-cient uptake by the roots, and reduces the chances of runoff of the insecticide from the application site.

3. Trunk injection. Measured doses of imi-dacloprid are delivered through a small tube that is inserted into holes drilled into the base of the tree. The number of doses required is deter-mined by the circumfer-ence of the tree. Trunk injection is not always effective, much more ex-pensive than the soil drench or injection, causes extensive tree wounding that contributes

to overall tree stress, and provides a shorter period of protection. However, this approach provides less chance for environ-mental contamination in rocky soils near open water. Most trunk injec-tions must be made by professional arborists.

Research has shown dra-matic recovery of HWA infested trees following applications of imidaclo-prid in residential set-tings. In the study, trees with little new growth but no dieback recovered most quickly; trees in poorest condition showed impressive recovery but it occurred more slowly.

Other Practices

Maintain tree health by irrigating trees during pro-longed dry periods and remove dead or dying limbs. Adelgid-infested trees should not be fertil-ized because adelgids thrive on fertilized trees. HWA can be moved from tree to tree by songbirds, so bird feeders should not be placed near hem-locks.

Life Cycle

An understanding of the HWA life cycle is useful because foliar sprays are most effective when the newly hatched "crawler" stage is active. Egg lay-ing begins early, before the first wildflowers bloom in early spring. Small red-dish brown nymphs (also called crawlers) that hatch from groups of up to 300 eggs in March ei-ther disperse from the tree or settle near the base of needles, sink their sucking mouthparts

into twigs, and begin to feed on sap. The crawl-ers have a distinctive white fringe around their sides, their white protec-tive covering is secreted later. Adelgids without the covering are very suscep-tible to contact with insec-ticidal soap or horticul-tural oil. 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 dur-ing 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 cov-ered by the white woolly material that they se-crete. Development re-sumes in late winter and continues until March when these adelgids ma-ture and begin the two generation per year life cycle again. In one year a single adelgid female could produce 90,000 offspring.

Movement and Dispersal

HWA was first reported in the eastern US in Virginia in the mid 1950's. Since then, it has spread north to Connecticut and south through North Carolina. It reached eastern Tennes-see in 2002, and was first reported in eastern Ken-tucky in spring 2006. The infested area expands at the rate of about 15 miles per year. HWA can be blown by winds, carried by birds and other wild-life, and moved on in-fested nursery stock. It

Page 6 Volume XIII, Issue V1

produces several genera-tions per year and has an extremely high reproduc-tive potential (up to 300 eggs per female) so num-bers can increase rapidly in a short time.

Impact on Forests and Landscapes

The HWA is established in about half of the hem-lock range in the eastern US and has killed about 90% of the hemlocks in Shenandoah National Park in Virginia. Tree mortality has caused a drastic shift in forest spe-cies composition. Be-cause hemlock provides extensive cover and shade and is so prevalent in watersheds and ripar-ian zones, their loss has drastic effects on ecologi-cal processes such as nutrient cycling, decom-position, leaching, stream temperatures, and stream organisms. Extensive hemlock mortality leads to a loss of hemlock-dependent wildlife. Song birds are especially at risk. Kentucky has a sig-nificant hemlock compo-nent throughout the east,

all of which is in danger of infestation by HWA. Ornamental plantings in urban settings are equally susceptible.

Biological Control

The HWA came from Asia without any of the natural enemies that keep populations in check in its native range. In addition, it feeds during the cooler parts of the year when our general predators are still dor-mant for the winter. Sev-

eral very small lady bee-tles have been imported and released in an at-tempt to provide some control of expanding HWA populations.

Outlook

Research on chemical and biological control techniques and resistant hemlock varieties is on-going. Proactive monitor-ing is essential for early detection of new infesta-tions. Isolated infesta-tions should be treated

immediately. Public edu-cation and coordinated information dissemination is needed to minimize the impacts of HWA in Ken-tucky.

Living adult female brown soft scales are pale yel-lowish-green to yellowish brown, often mottled with brown spots. Older fe-males are brown. The body is usually oval in outline, up to 3/16 inch in length and slightly convex in profile. The shape tends to vary according to position on the host plant.

Males are rare, but re-semble tiny wasps or flies.

Crawlers and young nymphs are yellow and almost flat in profile. Parasitized nymphs are dark brown to black and convex. Crawlers have well developed legs and antennae and are quite active until settling. Older nymphs are sessile.

Biology

Brown soft scale is cos-mopolitan in tropical and subtropical regions and in greenhouses in northern regions. In North America it occurs out of doors in the deep South, and north along the eastern seaboard to Virginia, and as far north as southern Vancouver Island on the west coast.

Brown soft scale has been reported feeding on hundreds of different

plants. It can survive on most greenhouse plants, but seems to prefer per-ennials to annuals. Ferns are a favored host.

Brown soft scale is a fre-quently encountered scale on plants indoors. Infestations of brown soft scale can become so heavy as to encrust the stems and petioles of their host plant. They also settle on leaves, usually along midribs and occa-

Brown Soft Scale James Baker, Extension Entomologist, NC State University

Page 7 Volume XIII, Issue V1

Redbay ambrosia beetle was introduced into the United States from Asia in 2002, most likely in solid wood packing materials, such as crates and pallets. By 2005, it was found to be consistently associated with mortality in an

expanded area of coastal South Carolina and Georgia. The range of redbay ambrosia beetle and associated redbay mortality continues to expand in Florida and coastal areas across the Southeast. Potential hosts include all members of the Lauraceae family such as Asian spicebush, yellow litsea, redbay, and sassafras. The

threatened and endangered species: pondspice and pondberry are of partiticular concern. The larvae are typical of scolytid beetles and are white, c-shaped, legless grubs with an amber colored head capsule. Adults are minute (1/16 inch), slender, and brown-black in color. Upon emergence, only the females seek a new host.

Not much is known about this beetle’s life cycle, but it is assumed to be similar to other Xyleborus beetles. Adults tend to attack weakened or recently killed hosts. Attacks are evident by pinhole-sized holes in the bark associated with either pitch flow or light-colored boring dust. Investigation under the bark often reveals galleries. As with other

Redbay Ambrosia Beetle www.invasive.org

sionally on the fruit. Large colonies remove large quantities of plant fluids and can cause wilting, but they seldom kill their host. Immatures and adults produce much honey dew that serves as a medium for the growth of sooty molds. These fungi inhibit photosynthe-sis and make infested plants unsightly. Obnox-ious insects such as ants and wasps are also at-tracted to feed on the honeydew.

Females retain their eggs in the body until hatching. Brown soft scales are born as active crawlers but remain under the body of the female for a

short time before emerg-ing and selecting a feed-ing site to settle and com-plete their development. Females molt twice be-fore reaching maturity. Males undergo four molts before emerging as winged adults, but are rarely seen. All stages are found throughout the year in warmer regions and in greenhouses. Brown soft scales can complete three to seven generations per year de-pending on temperature. It takes about 60 days to complete a generation.

Control

Brown soft scales are surprisingly difficult to

control even though there is no external egg stage, and only the body of the mother protects a few very young nymphs at any one time. Although reported as a pest spe-cies of many host plants in many countries, out-doors natural enemies in many areas may sup-press it. Scutellista cyanea Motschulsky is a common parasite and Metaphycus luteolus Tim-berlake controls brown soft scale in California.

The following pesticide formulations should con-trol brown soft scales if applied to infested plants thoroughly. A second ap-plication may be neces-

sary. Wait about 10 days between applications. Never set an ornamental plant out in the sun to treat it. Pesticide injury may result. Keep treated plants in the shade or treat during the cooler parts of the day so the foliage will dry before the plant is exposed to direct sunlight.

ambrosia beetles, the beetle transmits laurel wilt (Raffaelea lauricola) which serves as a food source for the beetle and also causes infected plants to rapidly wilt and die.

Emerald Ash Borer

The purple emerald ash borer (EAB) traps are being taken down across the state. All traps will be screened for presence of EAB prior to October 31. Our website will be updated with any new EAB finds www.KyStateEnt.org Movement of ash materials As a reminder—ash

materials are not allowed to be moved outside the quarantine area. If you move ash material (nursery stock, tree trimmings, firewood etc.) you are in violation and are subject to fines!

Inspector in Louisville With the need for public outreach and enforcement of the Emerald Ash Borer quarantine, Katie Kittrell’s office has moved to Louisville. Katie was stationed at the UK Research and Education Center in Princeton, KY. Being in Louisville, Katie will be more accessible to the people within the

quarantined area and also will give us a nursery inspector in an area of Kentucky which contains many nurseries and garden centers. Hopefully in the near future we will be able to fill the inspector position again in Princeton.

Office of the State Entomologist S-225 Ag Science Ctr—N Lexington, KY 40546-0091

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: State Survey Coordinator, nursery inspections

Phone: (859) 257-5838 Fax: (859) 257-3807

Princeton Phone: (270) 365-7541 ext. 204

Email: joe.collins@uky.edu carl.harper@uky.edu katie.kittrell@uky.edu janet.lensing@uky.edu