kentucky pest news, sept. 4, 2013

7/30/2019 Kentucky Pest News, Sept. 4, 2013

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Online at:www.uky.edu/KPN

Number 1355 September 4, 2013

FRUIT

-Spotted Wing Drosophila Update

SHADE TREES & ORNAMENTALS-Elm Yellows - A Sporadic Yet Lethal Disease of

Elm

-SawfliesLate Season Pine Defoliators

INVASIVE PESTS-Kudzu Bugs Found in Kentucky

HOUSEHOLD PESTS

-Brown Marmorated Stink Bug UpdateHornets and Yellowjackets

DIAGNOSTIC LAB HIGHLIGHTS

INSECT TRAP COUNTS

FRUIT

Spotted Wing Drosophila Update

Ric Bessin, Extension Entomologist

Problems with spotted wing drosophila (SWA)continue in commercial and backyard small fruit

plantings. Blackberries were particularly hard hit

by this new invasive insect with some commercialgrowers reporting near 100 infestations. The same

has been true for non-commercial plantings. Whilethe blackberry season is about over, fall raspberry

harvest is underway and is threatened by SWA aswell.

Figure 1. Spotted wing drosophila adults on a cracked

cherry tomato (Photo: Dr. Kenneth Yeargan).

I visited one commercial planting with blueberries,blackberries, and raspberries where we had been

using traps since the early summer. The growerindicated that the day we told him he had SWA, he

began spraying his susceptible crops with SWAmaterials on a weekly basis and has been gettingsatisfactory SWA control. I think the keys to his

success were:

Monitoring for SWA with traps. Using recommended SWA insecticides when

SWA was detected.

Getting through spray coverage inside thecanopy, in this case the grower used an air

blast sprayer.

Reapplying sprays to susceptible crops on a 5to 7 day interval during the harvest period

(shorter interval after heavy rains).

Observing pre-harvest intervals carefully.It is notable that the grower did not wait until he

found infested fruit before he began SWAinsecticide sprays. Had the grower waited to beginspraying the results may have been different. Myrecommendation for strawberry, blueberry,

blackberry, and raspberry growers next year to usetraps to monitor for the first instance of the adultsand be prepared to spray as soon as SWA is

detected.

There have been a number of questions aboutSWA infesting grapes. Grapes are not assusceptible to SWA as cane berries, but some thin

Lexington, KY 40546
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skinned types can become infested. Cracked orotherwise damaged berries are susceptible as well.

However, wine grapes will be crushed, the juicefiltered, and wild microbes killed. So, wine grapesare not as likely to suffer losses from SWA. Withtable grapes this may be different, particularly

with the thinnest-skinned types.

Home gardeners are less likely to spray regularlyand dont have the same options available. I dorecommend that the backyard crops be harvestedcarefully and soft berries disposed of. If the stem

end of the berry looks watery, it is likely infestedwith SWA. Sound fruit with a dry stem end should

be refrigerated immediately as this will arrest thedevelopment of eggs and any small larvae that

may be present inside the fruit. While washing theberries is a good practice for other reasons, it will

not rid the berries of eggs or the larvae inside.

SHADE TREES & ORNAMENTALS

Elm Yellows - A Sporadic Yet Lethal Disease of

Elm

Nicole Ward-Gauthier, Extension PlantPathologist

Elm Yellows, a lethal systemic disease of elm, was

confirmed on two American elm (Ulmus

americana) specimens in Franklin County inAugust 2013. The disease can occur in isolatedareas across the eastern portion of the U.S. and canquickly devastate large plantings of native elm.

Elm yellows occurs only occasionally inKentucky. In fact, only one other incidence has

been reported in the Commonwealth during thepast 30 years (Jefferson County, 1990).

Symptoms of elm yellows usually appear duringsummer months and include bright yellowing that

resembles early senescence (Figure 2). Leaves can

change hues with a few weeks, with petiolesturning downward (epinasty) (Figure 3). Leaveseventually turn brown and can remain attached to

branches for several weeks (Figure 4).

Figure 2. Foliar symptoms of elm yellows disease include

bright yellowing of leaves during summer.

Figure 3. Petioles droop and turn downward as elm yellows

disease advances.

Mature trees develop disease symptomsapproximately nine months following infection,while young trees may show symptoms in as little

as 3 months. Trees usually die within a year ortwo after symptoms develop. There is no cure.


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Figure 4. Within a few weeks of symptom development,

elm yellows causes leaves to turn brown. Leaves may fall or

remain attached to trees for several weeks.

The causal agent of elm yellows is a phytoplasma(bacterium-like prokaryote) called Candidatus

Phytoplasma ulmi. The pathogen inhabits phloem

tissue of elm, and as the pathogen builds up intissue, it becomes a metabolic sink for

photosynthetic products. Phloem then degenerates

downstream from these sinks, causing rootmortality in fine roots and subsequently in largerones. As this process ensues, tree canopies beginto show yellowing symptoms as described above.

Hosts of the elm yellows bacterium are limited toelm species, particularly native elm, including theAmerican elm (U. americana) and winged elm (U.alata). Chinese elm (U. parvifolia) is more

tolerant of infection and often remains unaffectedin areas where disease has killed native elm.

Spread of the bacterium is believed to be caused

by several species of leafhoppers and possiblyspittlebugs, although the white-banded elm

leafhopper has been confirmed as the primaryvector. These insects inoculate trees duringsummer or early autumn as they feed.

Control of elm yellows is not possible and controlof insects is not practical. Infected trees should be

removed as soon as possible to prevent spread ofdisease. Confirmation of elm yellows requires amolecular diagnostic test. Non-elm or tolerant elmspecies, including Asian species and hybrids,

should be used as replacement plants.

SawfliesLate Season Pine Defoliators

Lee Townsend, Extension Entomologist

Sawflies are members of the insect order(Hymenoptera) that includes ants, bees, andwasps. The larval stage has a caterpillar-like bodythat may be brightly marked with stripes or spots.

Some species change significantly in appearanceas they grow, making identification confusing.

Large numbers of sawflies can strip the needlesfrom a tree in a short period. Several species can

be found on pines in Kentucky.

Figure 5.

Introduced pine

sawfly larva

The European pine sawfly is one that is active atthis time of year. These olive green larvae withblack stripes and shiny black heads can feed on

many pines including Scotch, Eastern white, andAustrian. They feed on the previous year's needlesand do not damage new needles. These sawfliescan feed on twig bark, causing growth deformities.

Trees are seldom killed by the feeding of thisinsect during a single season. Full grown larvaeare about 1 inch long.

The introduced pine sawfly has a black head and

black body that is covered with yellow and whitespots. They prefer the needles of eastern white

pine but also will eat Scotch, red, Austrian, jack,

and Swiss mountain pine. Short leaf and Virginiapines have been attacked but usually are notheavily damaged.

Feeding is most severe in the crown to upper half

of the tree but heavily infested trees can becompletely defoliated. If this occurs after thewinter buds have formed, many branches or even


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the entire tree can be killed. There are twogenerations each year. The second generation of

this sawfly feeds on both old and new needlesduring August and September.

Sawfly populations are usually controlled by

combinations of natural enemies, predators,starvation, disease, or unfavorable weather.Outbreaks can occur when natural control does not

produce high mortality. Regular inspection ofpines will help to detect sawfly infestations beforethe larvae reach a size that can cause significant

defoliation. Since eggs are laid in clusters, feedingby groups of larvae can cause unsightly damage toornamental or landscape plantings, as well asnursery trees

If only a small number of colonies are present and

accessible, they can be handpicked, shaken off, orpruned from the tree and destroyed. Some of theinsecticides that can be used for sawfly control are

listed by the common name of the activeingredient followed by an example brand name.Acephate - Orthene Turf, Tree & Ornamental

Spray, bifenthrin- Ortho MAX Lawn & GardenInsect Killer, carbaryl - Sevin, cyfluthrin - Bayer

Multi-Insect Killer Concentrate, and permethrin -Ortho Tree, Shrub, and Lawn Spray. Althoughsawflies look like caterpillars, they are not

susceptible to Bt sprays.

INVASIVE PESTS

Kudzu Bugs Found in Kentucky

Doug Johnson, Extension Entomologist and

Garrard Coffey, ANR Agent, Whitley Co. KY.

Kudzu bug adults and juveniles (Figure 6) were

collected from Kudzu along Interstate 75 and U.S.Highway 25E and W. Knowing that Kudzu bug

movement was continuing toward Kentucky along

the I-75 corridor, and at last report was inClaiborne County, TN, which borders Bell and

part of Whitley County in KY, I thought it prudentto take some samples along I-75 in these

southeastern Kentucky Counties.

On Aug. 27 and 28 I traveled to this area and usinga 15-inch sweep net sampled kudzu patches alongI-75 and U.S. 25E and U.S. 25W in Whitley, Bell,

Knox and Laurel counties. This was a very small

and targeted sampling, designed to look in theplaces most likely to be infested. I collected live

Kudzu bugs in Whitley, Bell and Laurel counties. Isampled only a single location in Knox Countyand it was negative. All the positive samples

produced only small numbers of insects, a

maximum of 5 in 100 sweeps, but both adult andjuvenile forms were captured at multiple locations.It appears likely that the current population is notyet large, but reproduction is occurring. I did haveseveral negative samples, but the number ofsampling sites is so small, that zero probably does

not have much meaning.

I have no way of knowing just when these insects

arrived in KY as there was no sampling when thepopulation was at zero. Whether the insects Icaught first arrived in Kentucky this year or if

these are the offspring of overwintered kudzubugs is unknown. Perhaps a follow up survey in

2014 will give us some idea of how this pestoverwinters in Kentucky.

I do not believe that this population is a major

threat to Kentucky this year. However, if this pestis able to maintain itself in our region, particularly

by successful overwintering, it is likely to becomean important pest. The main agronomic cropaffected will be soybeans. However, this pestfeeds on a very wide range of plants, especially

legumes (a plant that has a shell like pod,containing multiple seeds, that splits in two halveswhen it ripens) like beans, lentils, peas, and

peanuts. In addition, this bug is a home invader. In

Figure 6. Adult and 2 juvenile Kudzu bugs (Photo: Philip

Roberts, University of Georgia)


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Figure 7 Football-shaped nest of

the bald faced hornet nest

(Photo: P. Meads)

fact, this is how the kudzu bug was first collectedin metro Atlanta. Home owners were calling their

pest control operators because the pest wascongregating in very large numbers on theirhouses.

I might suggest that homeowners who live nearKudzu may want to review the Publication:Entfact- 641 How to Pest-Proof Your Home,which may be obtained from your CountyExtension office or on-line at:http://www2.ca.uky.edu/entomology/dept/entfacts.

asp

My thanks to Stacey White ANR Agent in BellCounty for his help in finding sampling locations.

HOUSEHOLD PESTS

Brown Marmorated Stink Bug UpdateRic Bessin, Extension Entomologist

Brown marmorated stink bug (BMSB) will soonbe moving indoors as the fall weather changes. In

Lexington where it has been seen since 2010, theyhave been seen on the sides of buildings this past

week and will be moving indoors soon. WhileBMSB has been found in many counties (morethan 25), it has been at low levels in most of those

areas. The areas where we have seen it at higherlevels has been in the counties around Ashland,Louisville, Lexington, and Cincinnati. This pastsummer in my own yard, BMSB was seen on

cherries, apples, pears, green beans, blackberries,and raspberries.

Hornets and Yellowjackets

Lee Townsend, Extension Entomologist

Hornet and yellowjacket nests that have gone

unnoticed during the summer often becomepainfully apparent in early fall. These stinging

insects pose a threat to people who wander tooclose to or inadvertently disturb a nest. However,attempting to deal with it as a do-it-yourself

project can be even more dangerous. Onlyoverwintering queens survive the winter, all other

colony members die in the fall and the abandoned

nest deteriorates. Given time, the problem willsolve itself.

As Falstaff said, The better part of Valour, isDiscretion; in the which better part, I have savedmy life. Unless the nest inhabitants pose a direct

and serious threat because of the location of theirnest, Falstaff probably would vote for leaving thecolony to run its course and die naturally, or letsomeone else deal with it. Elimination of an activenest that is a threat is best left to a pest controloperator who is has the protective equipment,

expertise, and products to handle the task.

Here is a look at the common species:

Bald faced hornetThese black insects with whitish markings on their

faces and abdomens are about an inch long.Normally, there are100 to 400 workers

in a colony by thistime of year. Thefootball-shaped nest

is easily recognizedbut often hidden in

by foliage. Thehornets will defendtheir nest against

anyone who

approaches withinabout 3 feet oraccidentally jostlesit. Fortunately, this

species tends tonest relatively high which reduces chances ofinadvertent contact. The nest is abandoned at theend of the year and not used again.

European hornetThe inch-long yellow and brown European hornetis a formidable creature whose paper nest usually

is built in a hollow tree; however, they may live inattics, walls, and other voids with an outside entryhole. The nests are usually 6 feet or more aboveground level and are rarely exposed. The resident

population of a colony could be 1,000 workers butusually is in the range of 200 to 400.
http://www2.ca.uky.edu/entomology/dept/entfacts.asphttp://www2.ca.uky.edu/entomology/dept/entfacts.asphttp://www2.ca.uky.edu/entomology/dept/entfacts.asphttp://www2.ca.uky.edu/entomology/dept/entfacts.asp


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Figure 8. European hornetFigure 10. Yellowjacket (wings removed to show typical

markin s

European hornets nesting in or close to dwellingswill hunt in human-use areas, strip bark from

ornamental plants, eat tree fruits, and raiddomestic honey bee hives. They will defend theirnest if it is disturbed. Foraging workers generally

mind their own business but will sting if handled.

Figure 9.

Indoor nest

of the

European

hornet

Workers will fly at night and are attracted tolights. This makes evening control attempts muchmore exciting.

Yellowjackets

The term yellowjacket includes several species ofbright yellow and black wasps that frequently nestin the ground or in fallen trees. It is easy to disturb

yellowjacket nests when cleaning up around treestumps, landscape timbers, or in shrub lines.

Colonies may have 300 to 700 individuals. Somespecies are notorious scavengers that will return tosites for food and water.

Here are some general tips to reduce encounterswith hornets and yellowjackets:

Avoid leaving attractive resources outdoors.Keep pet food and water from being availablefor long periods of time. Use garbage bags intrash cans and keep lids in place. A dilute

solution of ammonia and water (approximately6 oz of ammonia (not bleach) per gallon ofwater) sprayed in and around trash cans and

sponged onto outdoor tables and foodpreparation surfaces may help to repel

yellowjackets.

Clean up fallen cracked and fermenting fruit. Thoroughly rinse recycled soda and juice

containers that are stored in accessible areas.

Stay away from known nests and be on thelookout for them when outdoors.

Keep food and beverage containers coveredwhen eating outside, yellowjackets will enteropen soft drink cans and can be ingested with

the liquid,

If you are attacked, brush off wasps or waspsand hornetswild swatting may attract moreand crushing them may release an alarm

chemical that attracts others to you.

Dont use scented soaps, shampoos, or lotionsif you are going to be working or hiking

outdoors. These odors can attract wasps andhornets to you.

Do not pour gasoline into yellowjacket nestsor hollow trees.

Wasp and hornet sprays that shoot a 20 foot

stream of insecticide are sold for treatment ofactive nests. They products typically have an

ingredient that will provide quick knockdown ofwasps emerging to defend the nest. If this


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approach is used, be sure to follow directions onthe container. Wear thick clothing to reduce

penetration of stingers and have eye and headprotection.

Wash sting wounds with and water to reduce the

chance of secondary infections. Use an ice bag toreduce the effects of the venom and apply lotionsthat reduce itching from insect stings. Seekmedical attention if you are stung in the mouth orthroat or if you experience severe swelling,dizziness, or difficulty breathing.

The following fact sheets are availableControlling wasps and yellowjackets -www.ca.uky.edu/entomology/entfacts/ef620.asp

and Foraging yellowjackets -www.ca.uky.edu/entomology/entfacts/ef634.asp

DIAGNOSTIC LAB HIGHLIGHTS

Julie Beale and Brenda Kennedy, Plant DiseaseDiagnosticians

Agronomic samples diagnosed in the PlantDisease Diagnostic Lab in the past week haveincluded boron deficiency, anthracnose, andsummer black stem & leaf spot on alfalfa; gray

leaf spot and Fusarium ear rot on corn;

anthracnose, stem canker, southern blight, suddendeath syndrome, and downy mildew on soybean.

On fruit and vegetable samples, we have

diagnosed Phytophthora root rot on blueberry;bitter rot, sooty blotch/flyspeck, and scab on

apple; bacterial spot on plum; downy mildew oncucumber; powdery mildew on pumpkin; bacterialspot and Fusarium fruit rot on pepper; root knot

nematode on potato; yellow vine decline onsquash; and early blight on tomato.

On ornamentals and turf, we have seen downymildew on impatiens; Volutella blight on

pachysandra; Cercsospora leaf spot on ash,hydrangea, dogwood, and redbud; Cryptocline and

Septoria leaf spots on birch; Phoma leaf spot oncrabapple; anthracnose and Phyllosticta leaf spoton maple; tip blight on pine and spruce; bacterialleaf scorch on oak; Pythium root dysfunction on

bentgrass; and Pythium blight on perennial

ryegrass.

2013 INSECT TRAP COUNTS

August 23 to August 30

Graphs of insect trap counts for the 2013 season

are available on the IPM Web site at -http://www.uky.edu/Ag/IPM/ipm.htm.

Note: Trade names are used to simplify the information

presented in this newsletter. No endorsement by the

Cooperative Extension Service is intended, nor is

criticism implied of similar products that are not

named.

Location Princeton, KY Lexington, KY

Black cutworm 0 0

Armyworm 1 8European corn

borer

0 0

Corn earworm 17 1

Southwestern corn

borer

2 0

Fall armyworm 0 0
http://www.ca.uky.edu/entomology/entfacts/ef620.asphttp://www.ca.uky.edu/entomology/entfacts/ef620.asphttp://www.ca.uky.edu/entomology/entfacts/ef634.asphttp://www.ca.uky.edu/entomology/entfacts/ef634.asphttp://www.uky.edu/Ag/IPM/ipm.htm.http://www.uky.edu/Ag/IPM/ipm.htm.http://www.uky.edu/Ag/IPM/ipm.htm.http://www.ca.uky.edu/entomology/entfacts/ef634.asphttp://www.ca.uky.edu/entomology/entfacts/ef620.asp

kentucky pest news, sept. 4, 2013

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