kentucky pest news august 31, 2010
TRANSCRIPT
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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).
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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.
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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.
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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 -
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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.
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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.
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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 -
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& 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.
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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.