kentucky pest news august 31, 2010

8/9/2019 Kentucky Pest News August 31, 2010

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Online at:www.uky.edu/KPN

Number 1245 August 31, 2010

ALFALFA

-Add Alfalfa Webworms to the Mix

TOBACCO-Disease Update

WHEAT

-Barley Yellow Dwarf

FIELD CROPS

-Why are there So Many/Fewer _(Fill in the

Name)_This Year?-Corn Earworm (aka Soybean Podworm) Moth

Flight Increases Dramatically-Fall Armyworm Moth Counts Have Sky

Rocketed!

ALFALFA

Add Alfalfa Webworms to the MixBy Lee Townsend

The alfalfa webworm has joined the fallarmyworm and alfalfa caterpillar in chewing on

alfalfa in some parts of the state this month. It

also will feed on soybeans. As the name implies,

these green to brown caterpillars with 6 blackspots on each body segment produce silk

webbing across the plant canopy as they feed.

They eat leaf tissue but leave the tougher veins.

These caterpillars feed at ground level and cause

cutworm type damage to seedlings. The larvalstage lasts for about 3 weeks and the caterpillars

may move in mass to adjacent fields if they

exhaust the food supply. Since this insect is onlya sporadic pest, there are no established

treatment guidelines.

Cutting the hay is a potential control measure if

it is in the appropriate stage. Few of the larvae

can survive the heat, low moisture, and direct

sunlight of curing hay. If this approach is used, it

FRUIT CROPS-Apple Variety Reactions to the Sooty Blotch

and Flyspeck Disease Complex

SHADE TREES & ORNAMENTALS

-Sawflies Late Season Pine Defoliators

-Stinging Caterpillars

PESTS OF HUMANS & PETS

-Fleas

DIAGNOSTIC LAB HIGHLIGHTS

is important to check for damage to regrowth by

any surviving caterpillars. Spotty outbreaks of

this insect were reported in Iowa in 2001 and

Illinois in 2002.

TOBACCO

Disease UpdateBy Kenny Seebold

Quite a bit of tobacco has been making its wayto barns during the past few weeks; however,

theres still a fair amount of tobacco waiting to

be cut. Blue mold has dropped to a low spot on

Lexington, KY 40546

Figure 1. Alfalfa webworm (M. Rice, ISU

photo).
http://www.uky.edu/KPNhttp://www.uky.edu/KPNhttp://www.uky.edu/KPNhttp://www.uky.edu/KPN


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the list of concerns, but frogeye leaf spot has

risen to the top of that list. We are getting some

reports of very severe outbreaks of this disease

(Figs 2-4), some of which are the worst cases

that I have ever seen. The most extreme damageseems to be occurring in low-lying fields near

creeks and rivers, or in places where fogs &dews have persisted until late-morning. When

high humidity and warm temperatures are

combined, we get the perfect conditions for thefrogeye pathogen, Cercospora nicotianae.

In terms of recommendations for our producers,

applications of Quadris (8 or more fl oz/A) may

be helpful at topping to suppress late-season

frogeye and also target spot. Late-season

frogeye can, under favorable conditions, lead to

a condition known as green spot disease which

results when infections by the frogeye leaf spotpathogen occur within 3-5 days of harvest. This

condition causes the appearance of small, green

spots on cured tobacco, and can result in lower-

quality leaf. A post-topping application of

Quadris can help reduce this problem and even

help maintain integrity of leaves in the lower

stalk positions. Id say this would be a good

recommendation where low-to-moderate

frogeye(and target spot) are present (Fig. 2). We

are seeing, though, cases of severe damage in

the flyings, lugs, and even leaf positions (Figs. 3

and 4). In these situations, it is unlikely that anybenefit will be achieved with an application of

Quadris. In fact, where disease is as severe aswe are seeing in Figs. 3 and 4, the grower would

probably not want to let the crop stand in the

field after topping, but would be better served to

cut that tobacco and house it immediately. With

this level of disease, its pretty likely that a near-total loss could occur over the 3-to-4 week

period between topping and harvest. In these

severe cases where tobacco is housed early, the

grower should expect to lose quite a few leaves

on the way to the barn, and even in the barn.Careful management of humidity in the barn will

be needed to avoid losses to house burn and barn

rots on these highly diseased and damaged

leaves.

For recommendations on the control of tobacco

diseases, please consult past issues of the

Kentucky Pest News, or the Kentucky-Tennessee

Tobacco Production Guide (ID-160), available

at

http://www.ca.uky.edu/agc/pubs/id/id160/id160.

pdf. Current tobacco disease status, images of

diseases (including frogeye), and additional

control recommendations can be found at the

Kentucky Tobacco Disease Information Pagelocated at

www.uky.edu/Ag/kpn/kyblue/kyblue.htm.

Figure 2. Burley tobacco with symptoms of frogeye.

Figure 3. Severe frogeye symptoms on tobacco.
http://www.ca.uky.edu/agc/pubs/id/id160/id160.pdfhttp://www.ca.uky.edu/agc/pubs/id/id160/id160.pdfhttp://www.ca.uky.edu/agc/pubs/id/id160/id160.pdfhttp://www.uky.edu/Ag/kpn/kyblue/kyblue.htmhttp://www.uky.edu/Ag/kpn/kyblue/kyblue.htmhttp://www.uky.edu/Ag/kpn/kyblue/kyblue.htmhttp://www.ca.uky.edu/agc/pubs/id/id160/id160.pdfhttp://www.ca.uky.edu/agc/pubs/id/id160/id160.pdf


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Note: I would like to thank Paul Sizemore,

ANR Agent for Owsley County, for sharing theimages used in Figs. 3 and 4.

WHEAT

Barley Yellow DwarfBy Don Hershman, Extension Plant Pathologist

Doug Johnson, Extension Entomologist

The current and projected high price of wheat ispredicted to encourage a significant increase in

wheat production in Kentucky next spring. It isalways important to maximize economic yield,

but this is especially true when each bushel of

wheat has a high value, and input costs are also

high. Barley yellow dwarf (BYD) is a virus

disease that can cause serious yield loss whenstunted and discolored plants are widely

distributed in a field. Severe losses due to BYD,

state-wide, occur about every five years or so,

but individual fields are impacted to varying

degrees each year. There are many diseases thatcan reduce wheat yields, but much of the BYD

management program is in place by the time

seed is sown in the fall. Thus, we thought it was

important to highlight BYD and control

measures at this time.

SYMPTOMS

The primary symptoms of BYD include plant

stunting, reduced tillering, and a yellow (Figure

5) to red-purple discoloration of leaf margins.

Affected plants may have an unusually erect

spiked appearance. Symptoms can occur in

the fall or spring, but they more commonlyoccur in the spring on the top two leaves of

plants. Foliar symptoms are frequently

accompanied by secondary bacterial infections.

Bacterial infections are visible as brown spots

and streaks on BYD-symptomatic leaves. Virus-

infected plants frequently occur in random,

small groups and along the edges of fields;

however, large portions of fields, even entire

fields, can be affected in severe cases.

DISEASE DEVELOPMENT IN RELATION

TO APHID BIOLOGY

Barley yellow dwarf virus (BYDV) is

transmitted from infected grasses into wheat and

barley by several species of aphids. In the fall,

the most important vector species are the birdcherry-oat aphid and, to a lesser extent, the corn

leaf aphid. In the spring, overwintered bird

cherry-oat aphids and English grain aphids arethe most important. Regardless of the aphid

species, winged adults immigrate into wheat

fields from neighboring and distant sites, feed,

and deposit live young on plants. The migratory

behavior of winged vectors is the reason why

initial BYD symptoms are often seen along field

edges and in randomly occurring groups of

plants. Typically, the young aphids deposited by

Figure 4. Whole-field view of severe frogeye infestation

on burley.

Figure 5. Typical yellowing of wheat leaves of plants

infected by Barley Yellow Dwarf Virus. Note the erect

appearance of discolored leaves compared to non-

symptomatic leaves, which tend to "flop" over.


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winged migrant adults develop into wingless

adults that produce more offspring over several

generations. These wingless aphids, in turn,

produce a small number of winged aphids,

which fly locally. They also produce a largernumber of wingless offspring that gradually

spread in fields by crawling from plant to plant.

BYDV is transmitted to wheat through the

feeding activities of both winged and winglessaphids. Aphids acquire the virus by feeding on

diseased plants (weeds and crop hosts) for as

little as 30 minutes. BYDV cannot move from

adult aphids to young aphids, however. For this

reason, the percentage of winged aphids

originally carrying the virus into a field is an

important piece of the picture. This percentage

can vary greatly from field to field, season to

season, and year to year. Although you cannever tell which aphids are carrying BYDV and

which are not, having knowledge of seasonal

aphid activities can help you assess the potential

for BYD to occur.

Fall infestation

The numbers of aphids arriving in the fall

depends largely on two factors: general growing

conditions the preceding summer and when the

first hard frost occurs in relation to wheat

seedling emergence. Normal or greater rainfall

during the preceding summer usually benefitsthe aphid population. In drier summers, fewer

aphids are produced, due to reduced host plantquality. For the same reasons, a greater

proportion of BYDV-infected host plants die

due to the extra stress. This can significantly

reduce the reservoir of BYDV available for

aphids to acquire, and later spread the virus, toemerging wheat plants.

Crops that emerge long before a hard freeze

have a greater potential for aphid infestation

(and exposure to BYDV) than those emergingafter a hard freeze. The fly-free date, which is

used to control Hessian fly infestations, is based

on this principle and also works well for aphids

as long as the freeze occurs when expected.This is the main reason why farmers are

encouraged to plant wheat after the Hessian fly

free date for their area.

Winter survival

Aphids arriving in the field during the fall

continue to move, feed, and reproduce as long as

temperatures remain above about 48F. Mild

temperatures or insulating snow cover duringcold spells usually result in significant survival

of the aphids during the winter. Harsher weatherresults in greater mortality. BYDV-infested

aphids that survive the winter months are a

primary source of BYD increase in the spring.

Spring infestation

The English grain aphid has a spring flight and

arrives about the same time that winter wheat is

greening up in early to mid-March. The

overwintering bird cherry-oat aphid becomes

active a little later in the spring. Because of the

earlier timing of overwintering English grain

aphids, this aphid species is somewhat lessimportant in the movement of BYDV in the

spring in KY compared to the bird cherry-oat

aphid.

BYD AND APHID MANAGEMENT

BYD management is imperfect in that complete

control is rarely, if ever, achieved. Still,

significant levels of BYD control can be

achieved using multiple management tactics aspart of an overall BYD management strategy.

PLANTING DATEPlant after the Hessian fly-free date in order to

minimize exposure of wheat seedlings to aphid

feeding and possible transmission of BYDV in

the fall.

VARIETIES

Plant wheat varieties that tolerate, or are

moderately resistant to, BYDV. There are no

highly resistant varieties, but some varieties are

considerably less impacted by the disease under

the same conditions.

SEED TREATMENT INSECTICIDES

Use of seed treatment insecticides is a relatively

easy, but not always economical, method of

aphid (and BYD) control. It is not a matter of

whether insecticides will kill aphids; they will.

Rather, the question is do you need to kill

aphids? Generally the most likely return on

investment will be for fields planted before the


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fly-free date. Sometimes, it is simply not

possible to plant all wheat acres after the fly-free

date. These early planted fields may good

candidates for use of seed treatment insecticides

because earlier emerging wheat provides alonger window for aphids to feed and transmit

BYDV to plants. Early infections also allowmore time for BYDV to reproduce in plants

before cold weather sets in. Earlier infections

have the greatest impact on crop yield and testweight the following spring. As the date of

seedling emergence becomes closer to the onset

of cold weather (as is usually the case when

wheat is planted after the fly-free date), the

chances of significant levels of aphid

transmission of BYDV decreases significantly,

and so does the need for seed treatment

insecticides.

The above notwithstanding, it must be noted that

a significant problem with applying seed

treatment insecticides is that they must be

deployed (and cost of treatment incurred) before

you can know if aphids will even be present in a

field. Early planting may open the door for

greater aphid activity (and possible transmission

of BYDV), but this is not certain just because a

field is planted early. As a result, that many

times seed treatment insecticides are used when

they are not needed. This unnecessarily

increases the cost of production. Makingapplications of foliar insecticides does not have

this problem as long as treatment decisions arebased on the results of field scouting for aphids

(see next section).

FOLIAR INSECTICIDES

Foliar-applied insecticides are an excellent

means of managing aphid populations (and

potential transmission of BYDV to wheat) if

aphid thresholds are reached. However, the

need to manage aphids is highly variable from

field to field, season to season, and year to year.As a result, spray decisions should be based on

results of intensive field scouting.

When to scout

In the fall, begin monitoring wheat fields for

aphids once seedlings have emerged and

continue until daytime temperatures remain

below 45F. In the spring, begin scouting when

daytime temperatures regularly exceed 45F;

continue scouting through the flag leaf

emergence (Feekes 8) growth stage.

How to scout

Examine three separate 1-foot lengths of row at

multiple locations in each field. Look over theentire plant, especially near the soil line. Countand record the number of aphids on each 1-foot

section of row, then calculate the average. This

sampling is for making decisions relative to

movement of BYDV. Label these records as

counts.

Economic threshold and use of foliar

insecticides

In the fall when estimating risk of BYD,

consider application of an insecticide if aphid

counts average three or more aphids per row-foot during the first 30 days after planting. An

average of six or more aphids per row-foot from

30 to 60 days post plant, or ten or more aphidsper row-foot thereafter, may justify the use of

foliar insecticides (refer to ENTFACT-121,

below).

The greatest probability for the successful (i.e.,economical) use of foliar insecticides exists

when the following criteria are met:

drought stress the previous summer was not

widespreadthe crop is planted prior to the fly-free date or

first killing frost

there is an extended period of mild weather in

the fall

the winter is mild and/or there is good snow

cover during cold periods

there is an early, mild spring

the crop has a high yield potential

high wheat prices are projected

If the aphids-per-row-foot threshold is reached

in the fall or spring, it is an indication that atleast some of the above criteria have been met.

If this aphid level is reached in the fall,

especially within 30 days of seedling emergence,

it may be advisable to make an insecticide

application. If it turns cold after the application,

wait and scout again in the spring. If the fall

and/or winter are mild and winged aphidscontinue to arrive in the field, continue to scout.


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It is possible that a second fall application might

be needed to achieve acceptable BYD control.

Regardless of what was done in the fall, a spring

application may be needed if late winter early

spring weather conditions favor the build-up ofaphid populations prior to flag leaf emergence.

Failure to make the necessary springapplications may negate any gains associated

with fall applications.

Keep in mind that the above aphid treatment

guidelines are not chiseled in stone. In some

years, the aphid thresholds may be too low and

in other years, too high. Herein is the difficulty

when attempting to control BYD indirectly

using insecticides: the system is not perfect.

However, until our understanding of BYD

epidemiology and aphid biology is enhanced by

new research, the aphids-per-row-foot treatmentguideline is the only one available with any

experimental basis.

ADDITIONAL RESOURCES

The following University of Kentucky

publications are available at County Extension

offices, as well as on the Internet.

Aphids and Barley Yellow Dwarf (BYD) In

Kentucky Grown Wheat, ENTFACT-121 (2004)

http://www.ca.uky.edu/entomology/e

ntfacts/ef121.asp

Comprehensive Guide to Wheat Management inKentucky: Disease Management Section 7, ID-

125 (2009)

http://www.ca.uky.edu/agc/pubs/id/id12

5/07.pdf

Comprehensive Guide to Wheat Management in

Kentucky: Insect Pests Section 8, ID-125

(2009)

http://www.ca.uky.edu/agc/pubs/id/i

d125/08.pdfKentucky Integrated Crop Management Manual

for Small Grains, IPM-4 (2009)

http://www.uky.edu/Ag/IPM/manuals/ipm4smgr.pdf

Kentucky Plant Disease Management Guide for

Small Grains, PPA-10c (1993)

http://www.ca.uky.edu/agc/pubs/ppa/pp

a10c/ppa10c.pdf

No-Till Small Grains Production in Kentucky,

ID-136 (2000)

http://www.ca.uky.edu/agc/pubs/id/id136/id136.htm

FIELD CROPS

Why are there So Many/Fewer _(Fill in the

Name)_ This Year?By Lee Townsend

Almost every year it seems that one or more

species of insects are more/less abundant than

normal. Sometimes increases are appreciated,as with lightningbugs or fireflies this summer.

Just a few years ago, we were wondering why

they were so scarce. On the other hand,

increases in pests of crops, landscape plants, orhumans can pose serious problems.

Weather, particularly temperature and rainfall,

have major impacts on insect survival which can

lead to significant increases (or decreases) in

insect numbers from one year to the next. And,

the effects are not consistent across species;

conditions that allow some to thrive may be

detrimental to others.

As a cold-blooded animal, insect development is

accelerated or slowed depending upontemperature. A very warm spring can shorten the

number of days required to grow from egg to

adult. In turn, rapid development can reduce the

length of exposure of vulnerable stages to

predators so that a smaller percentage is eaten by

natural enemies. It also can result in an extra

generation of the insect. Longer warm periods

also can mean species normally restricted to

southern regions can move further north.

Rainfall amount and timing also plays a big role

in insect population dynamics. Heavy springrains leave areas wet for prolonged periods of

time that favor some species. Increased nectar

and sap flow is a boon to nectar gathers and sap

feeders, including bees, butterflies, scale insects,

and aphids. And, fungus-feeding insects benefit

from an increased food supply. On the other

hand, these same rains can wash small
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caterpillars and sap feeders off of plants to

perish before they can find another host plant.

Weather also affects food abundance and quality

from the insects perspective. The highernutritional value of healthy, vigorous plants may

result in more rapid insect development andmore offspring per female. In some cases, plant

development may be better synchronized with

that of the insects that pollinate them or usethem as some other resource. The impact of

weather on some species can even be delayed.

The apparent increased incidence in attacks of

borers may be traced to the damage from past

ice storms or droughts that stress, weaken, or kill

trees and shrubs.

While temperature and rainfall have been

identified as driving the population dynamics ofmany insect species, a myriad of factors other

can be involved. In fact, the key factors

governing survival and success are somewhat

understood for only a few species. It is clear that

only small increases or decreases in the

relatively high mortality rate of most insects can

lead to very big fluctuations in their numbers.

Corn Earworm (aka Soybean Podworm)Moth Flight Increases DramaticallyBy Doug Johnson

Capture of adult corn earworm (CEW) moths in

the UK-IPM pheromone baited traps at

Princeton, KY has increased dramatically. The

total capture of CEW moths for the week ending27 August 2010 was 484, up from 82 on Aug

20th. This is the second largest capture of CEW

moths in the ca. 18 years of monitoring, with the

largest being 525 moths / trapweek in August

2001. (See a graphic display of this data at:http://www.uky.edu/Ag/IPMPrinceton/counts/ce

w/cewgraph.htm). This is not as dramatic an

increase as we are experiencing with fall

armyworm, nevertheless it is pretty unusual.(See: Fall armyworm moth counts have sky

rocketed! elsewhere in this issue of KPN).

Soybean- While it is too late in the season forcorn earworm to be of any importance on corn,

this pest also feeds on the pods of soybean,

especially late maturing varieties. (See: Fall

Armyworm, Corn Earworm and Sorghum WebWorm Active in Several Crops: in KPN 1244,

Aug 24, 2010 @http://www.ca.uky.edu/agcollege/plantpathology

/extension/kpnindex.htm).

Caterpillars (the damaging stage) resulting fromthese moths will begin to appear in 1-2 weeks.

Those individuals involved in soybean

production should scout their fields for the

presence of this insect. Corn earworm can beespecially damaging because it feeds directly on

the pods and seeds. Additionally, it is difficult

to scout as it does not feed to any great extent on

soybean leaves. One has to get into the plantsand look directly at the pods to find this pest.

Tobacco- CEW is also a considerable pest of

tobacco seed. CEW moths are attracted to

tobacco blooms and they will lay eggs on the

plants reproductive parts. Tobacco seed

producers should be watching their plants

carefully over the next several weeks.

Fall Armyworm Moth Counts Have Sky

Rocketed!By Doug Johnson

Capture of fall armyworm, Spodoptera

frugiperda (J.E. Smith) moths has sky rocketed

as indexed by the UK-IPM pheromone baited

traps at the UK-REC in Princeton,

KY.(Fortunately this does not seem to be the

situation in Lexington.) Last week (20 Aug

2010) our capture was a normal, 52

moths/trapweek; todays count (27 Aug 2010) is1,038 moths/trapweek! Please view the graphs

at:

http://www.uky.edu/Ag/IPMPrinceton/counts/fal

l/fawgraph.htm Because the trapping networkcaptures the adult moths (not damaging adult),

we have some lead time on the caterpillar

(damaging stage) population that will occur in

several weeks.
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WHY THIS YEAR IS UNUSUAL-

In 15 years of UK-IPM trapping of FAW, counts

have never before been this large.

The trap capture closest in size to this one (326

moths/trapweek ), occurred some five weeks

later in the year (Oct. 5 , 2007).

FAW has already been a significant pest inalfalfa this year (2010).

County Extension Agents are reporting FAW

damage on new lawn seedings.

ABOUT FALL ARMYWORM-

FAW is a migratory pest in Kentucky.Each

summer, adult moths move northward in

progressive stages from overwinter sites alongthe gulf coast region and begin to appear in

Kentucky in late June or early July. Small

numbers of FAW are often detected in corn,

grain sorghum, soybeans and other field crops,but is generally not a major pest. Because FAW

arrives during the summer, late planted corn and

grain sorghum, and double crop soybeans are

most at risk.

As the name implies, this insect can exhibit

armyworm behavior of walking in mass from

one location (usually heavily damaged) to

another (usually not yet infested).

Life Cycle & Description-The spherical gray

eggs are laid in clusters of 50 to 150, usually onthe leaves. Egg masses are covered with a

coating of moth scales or fine bristles. Larvae

hatch in 3 to 5 days. The six larval stages last for

a total of about 14- 15 days at this time of year.

However, the first three stages are quit tiny. The

final three stages that cause 99% of the total

damage, last about 7-8 days. Fall armyworm

vary from light tan to black with three light

yellow stripes down the back. There is a wider

dark stripe and a wavy yellow-red blotched

stripe on each side. Larvae have four pairs of

fleshy abdominal prolegs in addition to the pairat the end of the body.

Figure 6. FAW caterpillar stage. Color is variable.

Fall armyworm resembles both armyworm andcorn earworm, but fall armyworm has a white

inverted "Y" mark on the front of the dark head

(see the attached photo: FAW head.jpg). The

corn earworm has a orange-brown head, whilethe armyworm has a brown head with dark

honeycombed markings. Fall armyworm hasfour dark spots arranged in a square on top of

the eighth abdominal segment.

It is important to remember that we have had

FAW larvae present in Kentucky at varying

levels for more than six weeks. We probably

have overlapping generations at this time, so you

will not likely see distinct generations.

Food Source FAW feed on a wide variety ofplants. Corn, sorghum, and other plants of the

grass family are preferred hosts. Nevertheless,

fall armyworm may also attack alfalfa, beans

(including soybean), peanut, potato, turnip,

tomato, cabbage, cucumber, cotton, tobacco, and

clover.

CROPS AT RISK- Because of its very wide host

range many field and forage crops are at risk

from FAW, particularly when the population is

very large. A contributing factor can be the

absence of their preferred grass hosts (Moreimportant in the area of Kentucky that has

experienced drought conditions). FAW

populations are often larger in years when a cool

wet spring is followed by a hot humid summer.

Grass & Alfalfa forages- may be at the greatest

risk. These crops, especially newly seeded

stands. These should be watched closely. FAW

Figure 7. FAW head-on. Note

the inverted light colored Y

on the front of the head.


9/14

can wander around forage fields looking for

undamaged food. Do not confuse this with the

Eastern tent caterpillar (ETC). In Kentucky

FAW occurs only in late summer and fall, while

ETC occurs only in the spring.FAW does notmake silk tents in the crotches of trees that ETC

does. More importantly FAW does not have thesharp spines, that on ETC which makes it

damaging to foraging horses. (There is an

altogether different insect, the fall webworm thatmakes tents in trees this time of summer . It is

not the same insect as either the ETC nor the

FAW.)

Corn / Grain Sorghum- These crops are likely

too close to maturity for major damage from this

flight of moths.

Soybean -FAW is an occasional pest ofsoybean. It can however inflict serious damage

when populations are large. Later maturing

beans will be at greatest risk. FAW will feed

primarily on the leaf tissue. There is no specific

economic threshold. One needs to use the

defoliation damage in order to make control

decisions. Use Table 2 in ENT-13,(Soybean) in

Insecticide Recommendations for Field Crops .

(See link below.)

Fall Sown Newly Seeded Grasses- are often

infested by FAW. Examples of this occurrencein Kentucky include lawns, reclaimed mine

lands, road medians, right of ways, and grass

forages.

Wheat- Early seedings will be at the greatest

risk. However, if the current moth flight

develops into a large caterpillar population, early

emerging wheat should be scouted routinely.

Volunteer corn in wheat fields will attract the

FAW moths. In the past FAW have fed on the

corn and left the wheat. Fortunately, corn is a

preferred host and FAW will feed on it first.However, if the volunteer corn is depleted, I

assure you the FAW will move to the next best

thing.

Management

Planting at or after, the normal HessianFly free date will likely avoid all or

most FAW.

Scout fields for the presence of FAWand to determine if they are feeding on

wheat or volunteer corn.

If a field is heavily fed upon, do not rushto replant. Historically, this results in a

double stand. Grasses can recover from

FAW grazing. If necessary insecticides are available

for control. There is no specific

threshold.

General Control- FAW is relatively easily

controlled in all crops it is likely to be attack at

this time year. The most important part of

control will be finding the pest population before

it does significant damage to the crop. One

cannot put the damaged plant parts back in

place, so killing after the damage is done issimply Revenge Killing and will not help the

economic situation. I strongly advise against

trying to spray as a preventative! Spraying too

early is likely to remove any natural control

provided by predators, parasitoids and insect

diseases and is likely to make the situation

worse. The ideal action is to scout the fields and

apply a control tactic only if it is needed.

Insecticides for use against FAW on variousfield crops can be found in the 2010 Insect

Management Recommendations for Field Cropsand Livestock available at:

http://pest.ca.uky.edu/EXT/Recs/welcomerecs.ht

mlor at your County Extension Office.

FRUIT CROPS

Apple Variety Reactions to the Sooty Blotch

and Flyspeck Disease Complex

By John Hartman

Kentucky apples are being harvested now and

later varieties will continue to ripen through

autumn. Some growers may notice that their

apple fruits are covered with a black sooty

substance or tiny black specks. These

superficial dark smudges and spots are diseases

caused by fungi. Sooty blotch (Figure 8) and
http://pest.ca.uky.edu/EXT/Recs/welcomerecs.htmlhttp://pest.ca.uky.edu/EXT/Recs/welcomerecs.htmlhttp://pest.ca.uky.edu/EXT/Recs/welcomerecs.htmlhttp://pest.ca.uky.edu/EXT/Recs/welcomerecs.htmlhttp://pest.ca.uky.edu/EXT/Recs/welcomerecs.html


10/14

flyspeck (Figure 9) diseases are caused by a

complex of fungi involving up to perhaps 60

different species including Schizothyrium pomi,

Peltaster fructicola,Leptodontidium elatius , and

Geastrumia polystigmatis. Apple growersseeing some sooty blotch and flyspeck on early-

harvested apples should expect to see more asthe harvest season progresses according to a

research article published in the July 2010 issue

of Plant Health Progress. (This journal isavailable to U.K. employees through the Plant

Management Network at APSnet.org.)

The article, Relative Susceptibility of Selected

Apple Cultivars to Sooty Blotch and Flyspeck

by Alan Biggs et. al. was based on research done

in Massachusetts, New York and Virginia over a

period of several years. The researchers

evaluated apples from two sets of plantingsestablished in the 1990's involving 45 different

apple cultivars and lines. In general, sooty

blotch and flyspeck (SBFS) incidence for

different cultivars varied mainly by harvest date.

Cultivars that were harvested later in the fall had

the highest SBFS disease incidence although

orchard location was also important.

The first group of apples (listed in order of

increasing SBFS disease) included the early

maturing apples Sansa, Pristine, Sunrise, and

Ginger Gold; mid-season apples Arlet,Honeycrisp, NY75414, Golden Supreme,

Pioneer Mac, Creston, Gala Supreme, Yatake,and Senshu; and late-season apples Cameo,

Suncrisp, Orin, Enterprise, Fortune, Golden

Delicious, Shizuka, Braeburn, Fuji Red Sport,

and GoldRush. Average SBFS disease

incidence over several years and locations waslow in the early apples and up to 69% in the late

apples.

The second group of apples (also listed in order

of increasing SBFS disease) included the earlyseason apples Zestar, Silken, and NJ109; early

mid-season apples NY79507-72, Crimson Crisp,

Rogers McIntosh, September Wonder Fuji, NY

79507-49, and CQR10T17; late mid-seasonapples NJ90, BC 8S-26-50, NY65707-19,

Princess, Runkel, Scarlet O-Hara, and

Hampshire; and late season apples Pinova,

Ambrosia, Sundance, Delblush, Golden

Delicious, Cripps Pink, and Chinook. In this

group, average SBFS disease incidence was low

in the early apples but nearly 100 % in some of

the late apples.

Minimally managed apples in Kentucky

typically are covered with SBFS in mostseasons. These signs are more visible on yellow

fruit than on red or dark-colored fruit.

Prolonged periods of moisture and high

humidity favor appearance of SBFS, and

symptoms appear earlier in seasons with wet

spring and summer weather than under drier

conditions. Thus, it is possible that earlier

maturing cultivars may avoid disease by being

exposed to fewer hours of wetting and high

relative humidity, environmental factors

favorable for growth of SBFS fungi. Generally,

the longer fruit remain on trees withoutfungicide protection, the more likely it is that

SBFS fungi can develop and produce signs.

Growers applying fungicide sprays late in the

season, i.e., close to harvest, are usually

attempting to manage SBFS.

Apple orchards located on a northeast-facing

slope surrounded by woods will show more

SBFS incidence than orchards located on openland. The fact that maturation date and location

had the greatest impacts on SBFS incidence

suggests that cultivar resistance is unlikely tocontribute very much to integrated management

approaches for SBFS. Thus, in addition toorchard site selection, this study emphasizes that

SBFS management with fungicides cannot end

in late summer, but must be continued

throughout the harvest season, with particular

attention paid to late season cultivars.

Figure 8. Apple sooty blotch disease appearing

on the fruit surface.


11/14

SHADE TREES & ORNAMENTALS

Sawflies Late Season Pine DefoliatorsBy Lee Townsend

Sawflies are members of the insect order

(Hymenoptera) that includes ants, bees, and

wasps. The larval stage has a caterpillar-like

body that may be brightly marked with stripes or

spots. Some species change significantly in

appearance as they grow, making identification

confusing. Large numbers of sawflies can strip

the needles from a tree in a short period. Severalspecies can be found on pines in Kentucky.

The European pine sawfly is one that is active at

this time of year. These olive green larvae with

black stripes and shiny black heads can feed on

many pines including Scotch, Eastern white, and

Austrian. They feed on the previous year'sneedles and do not damage new needles. These

sawflies can feed on twig bark, causing growth

deformities. Trees are seldom killed by the

feeding of this insect during a single season. Full

grown larvae are about 1 inch long.

The introduced pine sawfly has a black head andblack body that is covered with yellow and

white spots. They prefer the needles of eastern

white pine but also will eat Scotch, red,

Austrian, jack, and Swiss mountain pine. Shortleaf and Virginia pines have been attacked but

usually are not heavily 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 the

winter buds have formed, many branches or

even the entire tree can be killed. There are two

generations 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

of pines will help to detect sawfly infestations

before the larvae reach a size that can cause

significant defoliation. Since eggs are laid in

clusters, feeding by groups of larvae can cause

unsightly damage to ornamental or landscape

plantings, as well as nursery trees

If only a small number of colonies are present

and accessible, they can be handpicked, shakenoff, or pruned from the tree and destroyed. Some

of the insecticides that can be used for sawfly

control are listed by the common name of the

active ingredient followed by an example brand

name. Acephate - Orthene Turf, Tree &

Ornamental Spray, bifenthrin- Ortho MAX

Lawn & Garden Insect Killer, carbaryl - Sevin,cyfluthrin - Bayer Multi-Insect Killer

Concentrate, and permethrin - Ortho Tree,

Shrub, and Lawn Spray. Although sawflies look

like caterpillars, they are not susceptible to Bt

sprays.

Figure 9. Apple flyspeck disease, appearing as

tiny black dots, and sooty blotch, both on the

fruit surface (C. Kaiser photo).

Figure 10. Introduced pine sawfly larva.


12/14

Stinging CaterpillarsBy Lee Townsend

Late season caterpillars are out in full force.

Many use camouflage or secretive behavior to

avoid predators, especially birds. A few are

protected and advertise their presence by brightwarning markings. These should be avoided.

The distinctive larva of the white flannel moth is

one of the less common species. They feed on avariety of deciduous trees and shrubs. These

caterpillars do not actively sting like a bee or

wasp. Contact usually comes as a person

accidentally brushes against a caterpillar that

they did not see.

Stinging caterpillars have some brittle, hollow

spines that are connected to venom glands in the

body. These spines easily penetrate skin and

break off. Then, the irritating venom goes towork. Reactions to the chemicals vary from

slight irritation to pustules, inflammation, and

sometimes intense pain.

Wide masking tape can be applied to the site to

lift these tiny spines from the skin. To avoid

further injury, the area should not be rubbeduntil they are removed. The wound area should

then be washed with soap and water. Place an

ice pack or cold compress on the wound

intermittently (15 minutes on and 15 minutes

off). See a physician if there is a severe orpersistent reaction to the toxin.

More information on stinging caterpillars found

in Kentucky is available in

www.ca.uky.edu/entomology/entfacts/ef003.asp

.

PESTS OF HUMANS & PETS

FleasBy Lee Townsend

Fleas seem to be especially common this year.

Dealing with an active infestation requires asignificant amount of time, patience, and effort

and an approach that includes both the pet and

its environment. Only an estimated 5% of the

fleas in an infestation are adults that are seen onanimals. About 50% are in the egg stage, 35%are larvae and about 10% are pupae. Persistence

and patience are essential. Concentrating on

control of adults without addressing immature

stages in bedding, carpets, and stuffed furniture

will keep flea control from being successful.

1. Treat the animal to kill adult fleas. Thenewest flea control products often are

available only through veterinarians but

many can be obtained at pet supply

stores or purchased on-line. Pet owners

should to visit with their veterinarianwhen using products to make sure that

they are compatible with other

treatments the pet may be receiving.

Here are some examples.

Brandname

Activeingredients

Pet Form Targets

ProgramProgram

Plus

lufenuron +milbemycin

oxime

Dogs Tablet

Adult fleas,heartworms

& othernematodes

Advantage9.1%imidacloprid

Dogs& Cats

Topical Adult fleas

Advantage

Multi

imidacloprid

+ moxidectin

Dogs

& CatsTopical

Adult fleas&

nematodes

Advantix8.8%imidacloprid

Dogs TopicalAdult fleas& ticks

Figure 11. White flannel moth caterpillar.

Beware of insects with bright warning

markings.

Figure 12. Close up of stinging spines on spots down

the back of the white flannel moth caterpillar.
http://www.ca.uky.edu/entomology/entfacts/ef003.asphttp://www.ca.uky.edu/entomology/entfacts/ef003.asphttp://www.ca.uky.edu/entomology/entfacts/ef003.asp


13/14

& 44%permethrin

FrontlineTop Spot

9.7% fipronil Dogs TopicalAdult fleas& ticks

FrontlinePlus

9.8% fipronil

& 11.8%methoprene

Dogs& Cats Topical

Adult fleas,

larval fleas,ticks

Revolution selamectin Dogs TopicalAdult fleas,larval fleas,nematodes

Zodiac

Spot OnPlus forCats

3.6%

methoprene +40%etofenprox

Cats TopicalAdult &larval fleasand ticks

ProMeris

for Dogs

14.3%

metaflumizon

e + 14.3%amitraz

Dogs Topical

Adult fleas,ticks,

demodectic

mangemites

ZodiacSpot on

FleaControl

45%

permethrinDogs Topical

Adult fleas& ticks

Comfortis spinosad Dogs Tablet Adult fleas

Many flea control products are designed to beused in a preventive program before pets are

infested. Specific formulations of the same

active ingredient may be separated for dogs orcats and also may be available for specific

weight classes to ensure a safe but adequate

dose. If a quick knockdown is needed, check the

product label and other information to see how

quickly you can expect results, some are much

quicker than others. Flea shampoos or dusts are

inexpensive but may not provide the lasting

protection of a topical treatment.

2. Control immature stages of the flea.Failure to do this is one of the most

common reasons for control failures.Female fleas lay their eggs on the

animal but the eggs are not stuck to the

pet so they fall off, usually onto the

surfaces where the animal sleeps or

regularly lays. The worm-like flea

larvae develop their feeding on dried

blood and feces. Mature larvae spin a

loose silk cocoon and pupate.

Ultimately, adult fleas emerge to repeat

the cycle. Eggs, larvae, and pupae

account for an estimated 95% of thetotal flea population. Unless these areas

are cleaned and treated, the infestation

will persist.

Look through each room to identify potential"hot spots". Here are some important steps totake-

Wash or clean throw rugs and petbedding in hot water to kill flea egg,

larvae, and pupae. If animals sleep with

family members, all bedding must be

washed.

" Steam clean or vacuum carpetsthoroughly everywhere the infested pet

is allowed to roam. Flea larvae are not

usually found in areas of heavy

pedestrian traffic or locations thatreceive exposure to sunlight; they are

likely to be present in areas where adult

fleas have left dried blood and feces.

" Treat areas where pets spend time(other than family beds) with an insect

growth regulator (IGR). Methoprene is

the most common one. Focus onlocations where pets go in and out of the

house; sleep and rest; jump off beds;

sofas and chairs; and other places where

they spend time with family members.

" Vacuum carpets, especially beneathfurniture and in areas frequented bypets. Use a hand sprayer to treat all

carpets with an insecticide that contains

an insect growth regulator. Allow carpet

to dry and vacuum a second time toremove additional fleas that were

induced to emerge. Continue to vacuum

for 10 days to 2 weeks to kill adult fleas

that continue to emerge from pupal

cocoons.

Vacuuming is very effective in picking up adultsand stimulating adults to leave their pupal

cocoons. Flea eggs, larvae, and pupae can

survive and develop inside vacuum bags andadults may be able to escape; immediately seal

them in a plastic trash bag and place them in a

covered trash container. Launder pet bedding in

hot, soapy water at least once a week.


14/14

Note: Total release aerosols ("room foggers") do

not provide the coverage and long-term

effectiveness of direct sprays unless they contain

an insect growth regulator. Treatments withinsecticides other than IGRs often fail to control

flea larvae because the treatment material fails tocontact them at the base of carpet fibers where

they develop.

Here are some example products that can be

used: Zodiac FleaTrol Carpet & Upholstery

Pump Spray 0.01% methoprene + 0.28%

permethrin; Zodiac Carpet & Upholstery Powder

2.5% linalool, 0.075% pyrethrins, 0.02% nylar

Fleas still around after treatments - The pupal

stage of a flea takes place in a loosely woven

silk cocoon. This stage is not affected by anyinsecticide or IGR applications so the adult must

emerge to be killed.

DIAGNOSTIC LAB HIGHLIGHTSBy Julie Beale and Paul Bachi

Recent agronomic samples in the PDDL have

included charcoal rot, stem canker, sudden death

syndrome and frogeye leaf spot on soybean;black shank and frogeye leaf spot (severe in

many cases) on tobacco.

On fruit and vegetable samples, we have

diagnosed Phytophthora root rot on blueberry;

Phytophthora collar rot on apple; blossom end

rot on pepper; Phytophthora fruit rot onpumpkin; Rhizoctonia stem rot on squash; early

blight, root knot nematode and buckeye rot on

tomato.

On ornamentals and turf, we have seen Pythiumand Rhizoctonia root rots and Alternaria leaf

spot on chrysanthemum; Rhizoctonia root/stem

rot on Shasta daisy, iberis and petunia;

Cercospora leaf spot on hydrangea; rosettedisease on rose; Rhizosphaera and Stigmina

needle casts on spruce; Phytophthora root rot on

arborvitae, cherrylaurel, taxus and viburnum;

Botrytis blight on hemlock; Pythium root rot onbentgrass; and brown patch on fescue.

kentucky pest news august 31, 2010

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