ENT-69: Integrated Pest Management: Kentucky Master Gardener ...
Kentucky Pest News April 12, 2011
Transcript of Kentucky Pest News April 12, 2011
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Online at:www.uky.edu/KPN
Number 1263 April 12, 2011
ALFALFA
-Sclerotinia Crown and Stem Rot of Alfalfa
TOBACCO-Disease Update for the Week of April 11
VEGETABLES
-EPA Approves the Use of Mancozeb on
Peppers and other Maneb-Only Vegetables-Recognizing Late Blight on Tomato Seedlings
WHEAT-2011 Wheat Fungicide Efficacy
FRUIT CROPS
-Fruit Disease Forecasting Using Kentucky
Mesonet Weather Data
ALFALFA
Sclerotinia Crown Rot and Stem Rot of
Alfalfa
By Paul Vincelli
Sclerotinia crown and stem rot (SCSR) was
diagnosed last week in western Kentucky,
causing substantial damage to a fall seeding of
alfalfa. This disease attacks fall-seeded stands
because the fungus produces spores in the
autumn, mostly from mid-October through
November. Spring-seeded stands usually have
adequate resistance to infection by the time
spores are produced. However, fall-seeded
stands are still vulnerable to infection, and so
they may suffer stand loss. The stand lossescaused by SCSR vary from minor to very severe
(Figure 1).
SHADE TREES & ORNAMENTALS
-Managing Flowering Crabapple Fire Blight
FOREST
-Periodical Cicada Emergence in West Kentucky
LIVESTOCK
-Time to Assess Eastern Tent Caterpillar (ETC)
Populations on Horse Farms
HOUSEHOLD
-Carpenter Bees
DIAGNOSTIC LAB HIGHLIGHTS
INSECT TRAP COUNTS
Symptoms and SignsSymptoms likely to be seen at this time of year
are as follows:
Yellowing, wilting, and browning ofrandomly scattered plants throughout
the planting. During humid conditions,
infected plants may exhibit white fungal
mycelium (Figure 2). These symptoms
are typical of ongoing infections, so
these fields will probably continue to
Lexington, KY 40546
Figure 1. Complete stand loss from a severe
outbreak of Sclerotinia crown and stem rot of
alfalfa.
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experience disease development for
several more weeks. If weather remains
generally cool and wet, disease
development could continue for as long
as 4-6 weeks. Sustained periods ofwarm, dry weather will arrest the
disease. Disease does sometimes cause complete
or nearly complete death of plants. In
other words, alfalfa seeded last fall may
simply fail to green up (as in Figure 1).For stands that were lush and vigorous
going into winter and then died during
winter, Sclerotinia crown and stem rot is
the most likely culprit (although not the
only culprit).
Look for fungal survival bodies called
"sclerotia" to diagnose this disease. The sclerotia
look like tiny black pebbles about 1/16 to 1/8
inch in size, with a white or gray center (Figure
3). They can be found attached to dead plants. If
plants have been rotted away, the sclerotia will
be scattered about on the soil surface where
plants once were present.
ManagementThere are a few alfalfa varieties that show partial
resistance to this disease. Complete resistance is
not available in commercial varieties, but partial
resistance can reduce stand loss caused by thisdisease. If considering a late-summer seeding, it
is important to use a variety that has been shownto exhibit partial resistance under field
conditions in Kentucky. This is important
because some of the worst disease pressure from
Sclerotinia crown and stem rot in the nation is inKentucky. Variety evaluations conducted in
other states are useful, but if a variety hasnt
been tested for resistance under Kentucky
conditions, it hasnt been adequately tested foruse in Kentucky.
The variety Phoenix has been shown to have a
significant level of Sclerotinia resistance underKentucky conditions, so that is certainly one to
consider for late-summer plantings. Be aware
that these varieties can still suffer stand loss
from the disease, but they will suffer
considerably less stand loss than the many
susceptible varieties on the market. Cimarron
SR is also a good choice from the standpoint of
Sclerotinia. Beyond these, I am unaware of
other varieties that have held up against the
severe disease pressure we sometimes get in
Kentucky.
Growers with crops sustaining outbreaks of this
disease should take this opportunity to determine
which fields are showing the problem. This will
help them identify fields in which to avoid fall
seeding in the future. The Extension publication
Risk Factors for Sclerotinia Crown and Stem
Rot in Fall-seeded Alfalfa
(http://www.ca.uky.edu/agcollege/plantpatholog
y/ext_files/PPFShtml/PPFS-AG-F-2.pdf) has
more information on the disease.
Figure 2. White fungal growth on rotting
alfalfa crown, indicating an active infection
of SCSR.
Figure 3. Black, hardened survival bodies of the
SCSR fungus (at arrow).
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TOBACCO
Disease Update for the Week of April 11By Kenny Seebold
Current Problems
In last weeks issue of Kentucky Pest News (No.1262), we took a look at two common, early-
season diseases of tobacco seedlings
Rhizoctonia damping-off and target spot. A few
cases of each have been reported over the pastweek (Figures 4 and 5), and I would expect
more to come given the recent warm-up and
subsequent spate of overcast, rainy weather.
From a management perspective, growersshould be focusing on providing good
ventilation for their plants (as much as is
practical given the weather), maintaining proper
fertility (~ 100 ppm N), and applying fungicideson regular schedule. The choice of fungicide touse depends on the age of seedlings in the float
bed. Plants that are dime-sized up to those ready
to clip should be treated on a 5-7 day schedule
with a mancozeb fungicide such as Dithane DF,
Manzate Pro-Stick, or Penncozeb 75DF at a rate
of 0.5 lb/100 gal of spray mixture (1 tsp / gal).
After the first or second clipping, the best option
would be Quadris applied at a rate of 4 cc per 5
gal of spray solution. The solution should be
sprayed onto 1000 sq. ft. of float bead (roughly
400 trays) so as to achieve good leaf coverageand stem rundown. Quadris can be used only
once on seedlings in the float system, so growers
must switch back to a mancozeb fungicide if
additional treatments are required. Refer to
Kentucky Pest News No. 1262 (April 5, 2011)
for more information, or consult the 2011-2012
Kentucky-Tennessee Tobacco Production Guide
(University of Kentucky Publication No. ID-
160).
Tobacco Fungicide News
A rumor has been floating around about the useof Dithane DF (and other mancozeb fungicides)
on tobacco seedlings, specifically that Altria
(PM USA) has prohibited the use of these
products in the float system. I have spoken with
an Altria representative regarding this, and have
been informed that the company has not banned
mancozeb on tobacco either on seedlings or in
the field. Growers should not be concerned
about applying mancozeb on tobacco at this time
and should consider its regular use in the float
system to manage diseases like Rhizoctonia
damping-off and target spot.
Some growers have also asked if Ridomil Gold
SL is now legal to use in the float bed to managePythium root rot. This probably stems from
language in the 24(c) label that was recently
approved that allows the use of this fungicide in
transplant water at setting time (Kentucky PestNews No. 1261, March 29 2011). Ridomil Gold
can only be used in the field, and cannot be
applied to float water; Terramaster EC is the
only product labeled for control of Pythium root
rot in float systems.
Figure 4. Damping-off caused by Rhizoctonia solani on
young tobacco seedlings (Photo: Jay Hettmansperger).
Figure 5. Early-stage target spot on tobacco
seedlings (Photo: Jay hettmansperger).
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VEGETABLES
EPA Approves the Use of Mancozeb on
Peppers and Other Maneb-Only VegetablesBy Kenny Seebold
In late 2008, all registrations for manebfungicides in the U.S. were cancelled by their
manufacturers. Maneb products are important
protectant fungicides used by many vegetableproducers in Kentucky and include Maneb 75DF
and Manex. There are also a number of maneb-
based home garden materials offered by
companies such as Hi-Yield and Bonide. The
main reason for the voluntary cancellation was
based on the high cost of maintaining the
Federal registration compared to the amounts
sold each year. Maneb was produced through
the end of 2008, and could be sold legallythrough the end of 2009.
The loss of maneb on certain crops took away an
important protectant fungicide and a valuable
tank-mix partner for fungicides that are prone to
the development of resistance. Whats more,
Kentuckys pepper growers have been advised
for years to mix copper fungicides with maneb
or the related fungicide mancozeb to help
improve control of bacterial leaf spot. It turns
out that these fungicides help make the copper
more effective against the bacterial pathogensthat cause this disease. Losing maneb has
therefore left us with a less-than-optimalchemical solution for pepper bacterial spot.
For some vegetable producers, the loss of maneb
has had very little impact. Growers who
produce sweet corn, cucurbits (except pumpkinsand winter squash), onions, potatoes, and
tomatoes can simply replace maneb with the
fungicide mancozeb, sold as Dithane,
Penncozeb, and Manzate. On the down side,
those who grow broccoli, cabbage, lettuce,peppers, pumpkins, and winter squash could not,
until recently, use mancozeb legally because of
label restrictions, even though maneb and
mancozeb are practically identical chemicals.
In early April, the EPA approved mancozeb for
use on several crops that had been previously
only on the maneb label broccoli, cabbage,
lettuce, and pepper. So far, only Manzate Pro-
Stick has this supplemental labeling, but other
mancozeb products (Dithane, Penncozeb) could
follow shortly. Late last year, approval was also
given to use mancozeb on pumpkins and wintersquash. The products that have the pumpkin /
winter squash labeling are Manzate Pro-Stickand Dithane DF. This is a great development for
pepper growers in particular, who now have a
replacement for maneb in the form of Manzate
Pro-Stick to use in tank-mixes with copper
fungicides to help suppress bacterial leaf spot.
As mentioned earlier, only Manzate can be used
on peppers, cabbage, broccoli, and lettuce fornow. For those growing pumpkins and winter
squash, either Manzate or Dithane can be used
as a direct substitute for maneb (Maneb and
Manex). Supplemental labels for either Manzate
or Dithane must be in the possession of thegrower when these products are used.
Recognizing Late Blight on Tomato SeedlingsBy Kenny Seebold
The vegetable growing season is upon us, and
garden centers are beginning to sell transplants
for homeowners. Commercial nurseries and
growers are also gearing up for transplanting.Tomatoes have always been a popular vegetable
crop for both home gardeners and commercialgrowers in Kentucky, and transplant-borne
diseases such as bacterial spot, bacterial canker,
and recently late blight, have caused serious
losses in some years.
ImportanceLate blight is an extremely important and
damaging disease of tomatoes and potatoes, and
occurs wherever these crops are grown. Until
recently, late blight was considered a minorproblem in Kentucky; however, a severe
outbreak in July, 2009 caused heavy losses to
home gardeners and commercial producers.
Although the source of this outbreak was neverdetermined, introduction on infected transplants
was suspected. In May, 2010, late blight was
confirmed on tomato transplants being sold by a
number of retail garden centers in central and
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northern Kentucky. No serious outbreaks
occurred that year because of the hot and dry
weather that prevailed, but losses would have
been high in a cooler, wetter summer due to the
sheer number of infected transplants that weresold to unsuspecting gardeners. Introduction of
this disease on transplants may or may not takeplace every year, but represents a threat to
tomato (and potato) producers in Kentucky.
Tomato seedlings that have late blight whentransplanted can serve as sources of inoculum
(spores) that can spread to nearby gardens and
commercial plantings, so every measure should
be taken to prevent these plants from making it
to the field. The added threat is that sources of
disease are introduced early in the tomato
production season, magnifying the potential for
heavy losses in seasons that favor late blight.
Learning to identify late blight on tomatoseedlings is extremely important for home
gardeners and commercial producers. This
knowledge will help prevent the unintentional
introduction of a devastating disease AND allow
other tomato and potato growers to be alerted to
a potential threat.
Symptoms and SignsOn seedlings, late blight first appears as circular-
to-irregularly shaped, water-soaked blotches on
leaves, petioles, and stems that expand rapidly
under favorable conditions (Figures 6 and 7). Inhumid environments, white and fuzzy fungal
growth may be present and indicates that spores
are being produced and released into the area.
Extensive blighting of foliage follows; death of
seedlings is common where stem infections
occur. If conditions become unfavorable for
disease after the appearance of symptoms,lesions can dry out, leaving brown-to-black
necrotic areas on foliage and stems.
Cause and Disease Development
Late blight is caused by Phytophthora infestans,a fungus-like organism belonging to a group of
microorganisms called oomycetes or water
molds. The late blight pathogen needs living
tissue to survive and does not generally
overwinter in Kentucky, as susceptible hosts are
killed during the cold winter months. The
pathogen does not survive on seeds, even if the
disease was present on the crop before seed were
extracted. Potential sources of inoculum(spores) that can affect tomato seedlings for
personal use or sale in Kentucky include:
volunteer potatoes; infected tomatoes in
greenhouses or other protected environment;
imported, diseased, planting material; and spores
blown in from areas where late blight is active.Tomato plugs or seedlings produced out of state
are thought to become exposed to the late blight
pathogen from infected volunteer tomatoes andpotatoes, susceptible weed hosts, or susceptible
plants such as tomatoes, eggplants, and petunias
(related to tomatoes) grown in greenhouses.
Late blight is most aggressive during periods ofcool and wet weather. The ideal climate for
infection and development is characterized by
cool nights (50-59o F) and warm days (70-79o F)
along with frequent periods of rain, fog, orheavy dew. Disease development is slowed or
stopped at temperatures above 86o
F, although
the pathogen can remain dormant in infected
tissue and re-emerge if temperatures fall back to
the disease-favorable range. During favorable
conditions, symptoms will appear around 5 days
after infection occurs, and spore production will
begin on infected tissue 1-2 days later. Large
numbers of spores are produced, and are then
spread by wind, water splash, or mechanical
contact. Thus, the disease can spread rapidly in
transplant production facilities and retail outlets.And once infected tomatoes make it into gardens
and commercial fields, a large-scale epidemic is
likely if weather is cool and rainy for extended
periods of time.
Tips for Buying Healthy Tomato Seedlings1. If possible purchase plants grown
locally from seed and not plugs brought
in from out-of-state. The risk from lateblight is generally lower on these types
of plants than on imported, finished
plants or locally-grown plants producedfrom imported plugs.
2. Look carefully at all plants on displayfor the characteristic symptoms and
signs of late blight (refer to figures).
The disease may be evident on just a
few plants in a garden center at first, andsymptoms will be mild. The disease
often develops earliest in shaded areas
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of the retail bench, particularly beneath
overhanging racks. Left unmanaged, the
disease can affect large numbers of
seedlings in a short time frame.
3. If you suspect that plants are infected bylate blight, alert your local Cooperative
Extension representative as quickly aspossible. Suspect plants need to be
tested quickly to confirm the presence of
late blight. This is important becausecertain diseases or environmental
problems can mimic late blight, and
laboratory tests are needed to provide a
positive identification. Do not buy
plants from retail outlets where late
blight is suspected until testing is
complete. It may seem reasonable to
just buy the healthy-looking plants
around those that appear to be diseased,but there is still risk if late blight is
active in the retail center. It takes
several days from the time a plant is
infected by the late blight pathogen to
the appearance of symptoms. Plants that
seem healthy could actually have the
disease and would certainly show
symptoms once brought home and
planted. If tests come back negative, it
should be safe to plant seedlings
purchased from that particular retail
outlet.4. Do not purchase tomato seedlings from
a retail center where late blight has beenconfirmed until all plants have been
destroyed and new, healthy stock
brought in. In cases where late blight is
confirmed in retail outlets, Cooperative
Extension will work with storemanagement to help bring the problem
under control.
5. As an added measure of safety, considerholding purchased plants in an isolated
area for a week before transplantingthem in the garden or field. Water the
plants as needed and watch for the
appearance of symptoms of late blight
(or other diseases and even insects).Plants that appear healthy after this
period will likely be safe to plant. If late
blight (or another problem) is suspected,
contact a representative of the
Cooperative Extension Service for
assistance in identifying the problem
before moving these seedlings outside.
WHEAT
2011 Wheat Fungicide EfficacyBy Don Hershman
Each year, the North Central Regional
Committee on Management of Small Grain
Diseases (NCERA-184) revises anddisseminates a fungicide efficacy table. Efficacy
ratings for each fungicide listed in the following
table were determined by field testing fungicides
over several years and locations by the members
of the committee. Efficacy is based on proper
application timing to achieve optimum
effectiveness of the fungicide as determined by
labeled instructions and overall level of disease
Figure 6. Darkened, irregular, and water-soaked
lesions on leaves or stems are typically seen on
seedlings affected by late blight.
Figure 7. Stem lesions typical of late blight on
tomato seedlings. These lesions may girdle the
stem and kill growth above that point.
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Propiconazole11.7%Azoxystrobin 7.0%
Quilt 200 SC14.0
VG VG VG VG E E VG NL Feekes 10.5
Propiconazole11.7%Azoxystrobin13.5%
Quilt Xcel 2.2SE
5
14.0--
3VG --
3--
3--
3VG --
3NL Feekes 10.5
Propiconazole
11.4%
Trifloxystrobin11.4%
Stratego 250 EC10.0
G VG VG VG VG VG VG NL 35 days
Tebuconazole22.6%
Trifloxystrobin22.6%
Absolute 500SC
5.0G --
3--
3--
3--
3E --
3NL 35 days
1Efficacy categories: NL=Not Labeled and Not Recommended; P=Poor; F=Fair; G=Good; VG=Very Good; E=Excellent. Efficacy
designation with a second rating in parenthesis indicates greater efficacy at higher application rates.
2Efficacy may be significantly reduced if solo strobilurin products are applied after stripe rust infection has occurred
3Insufficient data to make statement about efficacy of this product
4Multiple generic products containing the active ingredients propiconazole and tebuconazole may also be labeled in some states.
Products including tebuconazole include: Embrace, Monsoon, Muscle 3.6 F, Onset, Orius 3.6 F, Tebucon 3.6 F, Tebustar 3.6 F,
Tebuzol 3.6 F, Tegrol , and Toledo. Products containing propiconazole include: Bumper 41.8 EC, Fitness, Propiconazole E-AG, and
PropiMax 3.6 EC.
This information is provided only as a guide. By law, it is the responsibility of the pesticide applicator to read and follow all current
label directions. No endorsement is intended for products listed, nor is criticism meant for products not listed. Members or
participants in the NCERA-184 committee assume no liability resulting from the use of these products.
FRUIT CROPS
Fruit Disease Forecasting Using KentuckyMesonet Weather DataBy Paul Vincelli, Extension Plant Pathologist
John Hartman, Extension Plant Pathologist
Tom Priddy, Extension Agricultural
Meteorologist
John Strang, Extension Horticulturalist
For a number of years, the University of
Kentuckys Agricultural Weather Center has
offered weather-based disease prediction models
for the benefit of apple and grape producers in
making disease management decisions. Untilthis year, predictions of disease models for fruit
crops have been based on weather data available
from fifteen National Weather Service (NWS)
stations located throughout Kentucky. However,
disease predictions that have a greater
geographic reach throughout the
commonwealth are now possible. This is
because of the growth in recent years ofKentuckys Mesonet Weather System.
The Kentucky mesonet is a research grade
network of automated weather and climate
monitoring stations being developed by the
Kentucky Climate Center at Western Kentucky
University (http://www.kymesonet.org/). The
Kentucky mesonet currently includes 56 weather
stations, with more expected as funding permits.
If we base fruit disease predictions on mesonet-based data instead of NWS data, we can use all
56 mesonet weather stations to feed into themodels. Using the data in all these mesonet
stations should result in improved diseaseprediction for fruit producers, since there are
more likely to be nearby weather stations in the
mesonet network than the NWS network.
However, before switching our diseasepredictions to mesonet-based data, we wanted
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some assurance that the weather data feeding
into the models would be similar between the
two systems. We conducted a series of analyses,
but well only present two here for the sake of
brevity. In both cases, we focused our analyseson estimating the duration of leaf wetness
periods, for the following reasons:1. Wetness of surfaces of leaves, flowers,
and fruit is essential for infection by
many plant pathogenic fungi andbacteria. Many, many disease models
for crops all over the world are based in
some way on estimating leaf wetness
duration, including the models we make
available to apple and grape growers
through the UK Cooperative Extension
Service.
2. Estimating leaf wetness duration is
notoriously difficult and imprecise,much more difficult than measuring air
temperature or rainfall.
For our analysis, we gathered weather data for
the period 8 Apr to 2 Oct 2010 at UKs Research
and Extension Center at Princeton. We used
data collected by three weather stations at the
same site: the NWS station, the mesonet station,
and a Spectrum Technologies WatchDog
weather station. (Periodically, during the past
dozen years, three WatchDog units--located in
Quicksand, Lexington, and Princeton--haveprovided weather data used to generate fruit
disease forecasts issued by Dr. Hartman.)Results of the two analyses selected for
inclusion in this article are shown in Figures 8-9.
In Figure 1, it is clear that estimates of leaf
wetness using Mesonet data correlate to thoseobtained using the NWS station. Variance is
clearly present in those estimations, and in some
instances the difference in estimated duration of
leaf wetness is substantial. However, there is no
evidence of a significant systematic bias in theestimation of leaf wetness between those data
sources.
Figure 8. Comparison of estimates of leaf wetness
duration obtained using data from two nearby weather
stations. These estimates were calculated based on an
algorithm employed by the UK Ag Weather Center.
In Figure 2, one can see that leaf wetness
estimates correlated well between the two data
sources used in this analysis. The mesonet data
showed a slight tendency to underestimate
periods of leaf wetness at values, especially
below 5 hr of leaf wetness, but this difference
was not large and probably wouldnt be
epidemiologically significant for most disease
outbreaks.
Figure 9. Comparison of estimates of leaf wetness
duration obtained using Mesonet data and a Spectrum
WatchDog unit. These were calculated using similar
algorithms (although the algorithm used on mesonet
data included wind speed, data which were not available
in the WatchDog unit).
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ConclusionThe growth of the Kentucky mesonet network
provides a more comprehensive weather
network for prediction of crop diseases than has
been previously available. Our analyses suggest
that disease forecasts based on these data should
be useful to fruit producers. Given theincreasing coverage of the mesonet network
(with currently 56 stations statewide), we expect
that the mesonet system will provide more local,fine-scale resolution than can be obtained with
either Spectrum WatchDog units located on UK
research stations or NWS weather stations
(which currently number 15 statewide). Disease
models incorporating mesonet data are available
http://wwwagwx.ca.uky.edu/kymesonet2.html.
SHADE TREES & ORNAMENTALS
Managing Flowering Crabapple Fire BlightBy John Hartman
Kentucky flowering crabapples, flowering now,
are enjoyed for their profuse flowers and for
their attractive foliage and fruit. Experienced
growers and homeowners are well aware that
springtime is also the time of year that many of
the important diseases of flowering crabappleare most active.
Many flowering crabapples are made unsightly
or are severely injured by one or more of fivecommon diseasesapple scab (discussed in
Kentucky Pest News two weeks ago), fire blight,
cedar-apple rust, cedar-quince rust, and powdery
mildew. Injury due to fire blight infection is
often obvious in the tree because in spring andearly summer, twigs and small branches are
dead and blackened.
Managing fire blight (Figures 10 & 11) causedby the bacterium Erwinia amylovora:
While trees are dormant, prune outshoots killed by fire blight the previous
year.
Remove water sprouts and root suckerswhen they are small.
Remove nearby neglected pear andapple trees from the nursery or
landscape because these trees can be a
source of overwintering fire blightbacteria.
Plant fire blight-resistant crabapples in
new plantings. Ratings vary from onepart of the country to the other,
however, the following cultivars are
thought to be more tolerant of fireblight: Adams, Adams Dwarf,
Callaway, Candied Apple,
Christmas Holly, David, Dolgo,
Harvest Gold, Indian Summer,
Jewelberry, Liset, Malus sargentii,
M. yunnanensis var. veichii, M. zumi
Calocarpa, Pink Princess, Pink
Spires, Prairiefire, Profusion,
Radiant, Red Baron, RobinsonDwarf, Royalty, Selkirk, Sentinel,
Spring Snow Dwarf, and Velvet
Pillar.
Antibiotic sprays such as streptomycincan be used to protect open flowers from
infection. Antibiotic sprays are bestused in the nursery, and not in the
landscape. Use of a computer model
such as Maryblyt or Cougarblight for
timing of fire blight sprays is most
useful.
Nursery growers may consider using thefire blight predictive system available toapple growers on the U.K. Ag Weather
Center site
(http://wwwagwx.ca.uky.edu/kymesonet
2.html). The predictive system worksbecause the weather and fire blight risk
parameters are the same for apple and
crabapple. These predictive systems
have already indicated that flowering
crabapples with open flowers were athigh or extreme risk for fire blight
earlier this week on both Saturday andMonday. After flower petals fall in the
coming days, the risk of primary fire
blight infections drops to low levels.
However, from primary infections that
already occurred, secondary shoot
infection symptoms will continue to
appear for the next several weeks.
http://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.htmlhttp://wwwagwx.ca.uky.edu/kymesonet2.html -
8/7/2019 Kentucky Pest News April 12, 2011
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For all but the most susceptible trees,infections are normally halted by thetree before the bacteria actually kill the
tree. Thus, infected branches are best
removed in winter.
Avoid promoting succulent growth that
favors fire blight.
FOREST
Periodical Cicada Emergence in WestKentuckyBy Lee Townsend
Periodicalcicadas
that make
up Brood
XIX soon
will beleaving the
quiet life
they have
been
leadingundergro
und as sap feeders on tree roots. After for 13years in the dark, nymphs will crawl up vertical
surfaces and molt to loud (males), active adults(both sexes) that will buzz around clumsily for
about 6 weeks.
These insects differ from the dog day cicadas
that we see near the end of every summer. Theyare smaller and have red eyes and red-orange
wing veins; these structures on the larger dog
day cicadas are green. Erratic fliers, cicadas
often stay in the upper canopy of trees where
they are active from late April through June.Encounters with periodical cicadas can be
unnerving but these insects cannot sting and do
not harm humans, livestock, or pets. Except for
the occasional dog or cat that will suffer an upset
stomach from eating too many.
The estimated time table for Brood XIX:
Emergence begins late April or early May
Most out by late May. Males begin to call
females for mating
Egg laying will begin in mid-May
Last adults will disappear around mid-June
Brood
XIX
will be
active in
westernKentuck
y and
Figure 10. Fire blight, shown here on a flowering
pear flower cluster, similarly attacks flowering
crabapple flowers before spreading to the
nearby branches.
Figure 11. Fire blight branch infection
showing typical shepherds crook symptom.
Figure 12. Periodical cicada molting to an
adult.
Figure 13. Counties where periodical cicadas
were active in 1998.
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parts of Alabama, Arkansas, Georgia, Indiana,Illinois, Louisiana, Maryland, Missouri,
Mississippi, North Carolina, Oklahoma, South
Carolina, and Tennessee.
Please send observations and pictures of the
brood [email protected]. Examples ofuseful information include your location, date
you first noted emergence, estimated abundance
(light moderate heavy), date males started
singing, egg-laying beginning, or other thingsyou find interesting. This information will be
posted at
http://pest.ca.uky.edu/EXT/Cicada/kycic2011.ht
ml
LIVESTOCK
Time to Assess Eastern Tent Caterpillar
(ETC) Populations on Horse FarmsBy Lee Townsend
Over the
past 3 years
ETC
populationshave been
increasing
gradually
but there
arerelatively
wide
differences
in numbers from one area to another. This is
normal for the dynamics of the insect.
ETC larvae should be mostly in the 0.5 to 0.75inch range in central Kentucky. The caterpillars
are beginning to move from 2- to 3-inch long
tents near their egg mass to larger masses at
major branch forks. Most tents should be in the
baseball to softball size, making them easy to
see in trees on a sunny day. Consequently, now
is the time to check for tents along pasture and
paddock tree lines that contain wild cherry, if
pregnant mares are present. Any management of
the caterpillars should be done while they are
together in tents. If is essentially impossible to
provide effective control once they have
dispersed from host trees.
One option is to move pregnant mares awayfrom identifiable concentrations of ETC. If this
is not practical, then physical removal of tents,
or spot treatment with insecticides is an
alternative approach.
ETC was identified at the cause of foal loss
during the Mare Reproductive Loss Syndrome
outbreak that occurred during 1999-2001.
HOUSEHOLD
Carpenter BeesBy Lee Townsend and Mike Potter
Carpenter
bees
(picture)
closely
resemble
bumble bees
but havebare, shiny
black
abdomens.
Bumble beeshave hairy
abdomens
with at least some yellow markings. Bumble
bees nest in the ground, while true to their name,
carpenter bees chew tunnels into wood toconstruct nesting sites.
Carpenter bees spend the winter in their galleriesand begin to feed on nectar and pollen aroundearly April. Females may begin a new nest or
use the existing one. The entryway is a round 0.5
inch diameter hole in the underside of a soft
wood board. The gallery soon turns 90 degrees
and follows the wood grain. Sawdustaccumulates beneath the tunnel opening as the
female extends it. The bees prefer bare or
Figure 14. ETC tent with massed
caterpillars.
Figure 15. Carpenter bee gathering
nectar and pollen.
mailto:[email protected]:[email protected]:[email protected]://pest.ca.uky.edu/EXT/Cicada/kycic2011.htmlhttp://pest.ca.uky.edu/EXT/Cicada/kycic2011.htmlhttp://pest.ca.uky.edu/EXT/Cicada/kycic2011.htmlhttp://pest.ca.uky.edu/EXT/Cicada/kycic2011.htmlhttp://pest.ca.uky.edu/EXT/Cicada/kycic2011.htmlmailto:[email protected] -
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weathered wood but a coating of paint or stain
will not guarantee the wood wont be used.
Liquid sprays of carbaryl (Sevin) or a pyrethroid
(e.g., permethrin or cyfluthrin) can be applied as
a preventive to wood surfaces which areattracting bees. Residual effectiveness of these
insecticides is often only 1-2 weeks, however,and the treatment may need to be repeated.
Tunnels which have already been excavated are
best treated by puffing an insecticidal dust (e.g.,5 percent carbaryl) into the nest opening.
Aerosol sprays labeled for wasp or bee control
also are effective. Leave the hole open for a few
days after treatment to allow the bees to contact
and distribute the insecticide throughout the nest
galleries. Then, plug the entrance hole with a
piece of wooden dowel coated with carpenter's
glue, or wood putty. This will protect againstfuture utilization of the old nesting tunnels and
reduce the chances of wood decay.
Although carpenter bees are less aggressive than
wasps, female bees provisioning their nests will
sting. Treatment is best performed at night when
the bees are less active, or while wearing
protective clothing.
Females begin to provision the gallery with
pollen and deposit eggs during May. Bee
development takes 40 to 50 days and 8 to 9 beesare produced in an average gallery. Emerging
bees are not very active, they remain in thetunnel for most of the summer and fall and take
up the bee life in the spring. Some females
live for two years.
DIAGNOSTIC LAB HIGHLIGHTSBy Julie Beale and Paul Bachi
Recent samples in the PDDL have included
Sclerotinia crown/stem rot and Pythium root rot
on alfalfa; white rot (Sclerotium cepivorum) on
garlic; and black root rot and Pythium root roton greenhouse petunia plugs.
On landscape ornamentals, we have seen black
root rot on holly; stippling from previous spider
mite infestation on holly and taxus; Stigmina
needle blight on spruce; and stress symptoms on
white pine.
INSECT TRAP COUNTSApril 1 - 8
Graphs of insect trap counts for the 2011 season areavailable on the IPM web site at -http://www.uky.edu/Ag/IPM/ipm.htm.
View trap counts for Fulton County, Kentucky at -http://ces.ca.uky.edu/fulton/InsectTraps
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 8 0
Armyworm 194 452
Corn earworm 1 0
European corn
borer
0 0
Southwesterncorn borer
0 0
Fall armyworm 0 0