Kentucky Pest News Newsletter

HIGHLIGHTS IN THIS ISSUE

Number 1017__________April 19, 2004

ANNOUNCEMENTS
TOBACCO
CORN
SMALL GRAINS
WHEAT
FRUIT
SHADE TREES AND ORNAMENTALS
HOUSEHOLD
DIAGNOSTIC LAB HIGHLIGHTS
IPM TRAP COUNTS


God bless America

ANNOUNCEMENTS



TRUE ARMYWORM FLIGHT CONTINUES
By Doug Johnson

Capture of True armyworm in pheromone baited traps continues, and has increased slightly. Although this pest is always a threat, numbers as indicated by our trap catches, do not appear to be out of the ordinary. Certainly they are no where near the numbers captured in the outbreak of 2001.

You may view pheromone trap data for field crops on the IPM Web pages at: http://www.uky.edu/Agriculture/IPM/ipm.htm . Just select "Pheromone Trap Counts" from the menu bar. This site holds current and historic data for a number of insect pests of KY field crops.

Armyworm will be found in every small grain field if enough time is taken to look for them. However, they are rarely of economic importance. The most important time period will be during head fill and maturation. If "head clipping" occurs,the possibility of needing a treatment occurs but almost no other feeding is of importance.


Ky Blue Mold

TOBACCO



FLOAT PLANT PESTS
By Lee Townsend

Floats Gnats and aphids are common insects that appear on tobacco float plants as structure covers or sides are moved or raised on warm sunny days. Occasionally some other insects will show up that can damage transplants. In past springs, small black dung beetles have been found burrowing into tray media in outdoor transplant float trays. Usually, these beetles would be attracted to moist, decaying organic matter to feed and lay eggs. The beetles that have been found in tobacco trays were not feeding on small transplants but dig extensively in the growth media, uprooting seedlings that soon shriveled and died. The hard body and wing covers of the beetles make them a challenge to control even with a direct spray of an insecticide. Orthene 97 can be used as a foliar spray in greenhouse transplant production at the rate of 3 / 4 tablespoon per gallon of water per 1,000 square feet of bed against aphids, flea beet and cutworms. It may provide some control of dung beetles as a direct contact spray.

For the latest blue mold status and other tobacco disease information, check the KY Blue Mold Warning System online.
Blue Moldhttp://www.uky.edu/Agriculture/kpn/kyblue/kyblue.htm

For more information about tobacco pests, visit "Insect Management Recommendations".



Corn






CORN



COOL, WET SOILS INCREASE RISK OF DAMPING OFF
By Paul Vincelli

Corn In most of the Commonwealth, soils were wet with temperatures in the high 40's to lower 50's F For most or all of the period of April 11-16. These conditions are very favorable for development of infections of corn seedlings by the soilborne organism Pythium ultimum, the most common cause of seed rots and seedling damping of field corn in Kentucky. P. ultimum thrives in saturated soils. While it actually prefers warmer soils, soil temperatures in the range of 48-53 F severely curtail the ability of the corn seedling to defend itself against infection. Thus, a period of cool wet soil conditions like we had last week can favor stand loss from P. ultimum, particularly if the corn seed is of low vigor or the crop is under stress for some other reason.

Fungicidal seed treatment with either metalaxyl or mefanoxam provides very good protection against P. ultimum for a period of 10 days, perhaps longer under some conditions. However, as of Sunday, April 11, 40% of the intended corn acreage had been planted, compared to 13 percent for the five-year average. With so much of the corn in the ground, it is likely that some crops were exposed to this period of cool, wet soil conditions after the fungicide had lost its effectiveness.

Since corn yields are strongly influenced by plant population, it would be advisable for producers to scout fields for plant populations 2-4 weeks after emergence.

Guidelines for assessing stands are available in the Extension publication Kentucky Integrated Crop Management Manual for Field Crops: Corn, IPM-2.

For fields with stands that are poorer than expected, the publication A Comprehensive Guide to Corn Management in Kentucky, ID-139, provides producers with guidelines for determining whether replanting is likely to be advantageous or not. This information is in the chapter on "Planting Practices".


POSTEMERGENCE CONTROL OF BROADLEAF SIGNALGRASS IN CORN
By James R. Martin

Corn Broadleaf signalgrass is a competitive warm-season annual grass that frustrates a number of Kentucky's corn growers. While there are a number of soil-residual herbicides used to manage this weed, the control they provide tends to be inconsistent, especially in no-tillage. Consequently, postemergence herbicides play an important role in controlling broadleaf signalgrass in corn.

Broadleaf signalgrass looks similar to some species of crabgrass, especially during early growth stages. In order to distinguish between signalgrass and crabgrass, young seedlings need to be developed enough to where the ligule (a tongue-like structure on the inside of the collar) is visible. The ligule of broadleaf signalgrass is a small ring of hairs compared with a large membrane-like ligule for crabgrass plants.

UK research shows that postemergence applications of Accent can provide approximately 90% control of broadleaf signalgrass. There are a number of other postemergence products capable of providing similar results, yet timing of application and rate of herbicide are important factors affecting control.

The following table provides rate of postemergence broadcast herbicides and maximum height of broadleaf signalgrass.

HERBICIDE RATE BROADLEAF SIGNALGRASS SIZE
Accent 0.67 oz/A 2"
Basis Gold 14 oz/A 2"
Celebrity Plus 4.7 ox/A 2"
Equip 1.5 oz/A 2"
Liberty (LL corn) 20 oz/A 2"
Liberty (LL corn) 34 oz/A 5"
Liberty ATZ (LL corn) 32 oz/A 2"
Liberty ATZ (LL corn) 40 oz/A 4"
Lightning (Clearfield corn) 1.28 oz/A 8"
Option 1.5 oz/A 2"
Ready Master (ATZ RR corn) 2 qt/A 2"
Glyphosate (3lb ae/gal) (RR corn) 1.5 pt/A 5"
Glyphosate (3lb ae/gal) (RR corn) 2 pt/A 7"
Steadfast 0.75 oz/A 2"
Steadfast ATZ 14 oz/A 3"

Antagonism can occur when these herbicides are tank mixed with other products. Reduced control of broadleaf signalgrass has been reported when Accent is combined with Marksman, Buctril, or 2,4-D. Although the antagonism has not been consistent in all studies, it may be wise to consult product labels before using tank mix combinations for broadleaf signal grass control.

Post-directed applications of Gramoxone MAX can be an effective and economical method for controlling broadleaf signalgrass in corn. However, very few corn farmers are equipped to do this method of application.

For information about corn pests, visit "Insect Management Recommendations".


Wheat

WHEAT


 


FOLICUR: A NEW TOOL FOR MANAGING FUSARIUM HEAD BLIGHT IN WHEAT
By Don Hershman

Wheat
Fusarium head blight (FHB) of wheat, and deoxynivalenol (DON) accumulation in harvested grain, are periodically very serious problems in Kentucky. On April 15, 2004, the Environmental Protection Agency approved Kentucky's Section 18 application which sought emergency labeling for Folicur 3.6F to help with FHB/DON management during 2004. Folicur is manufactured by Bayer CropScience. This new fungicide tool, when used with other FHB/DON management tactics (see http://www.ca.uky.edu/ukrec/newsltrs/news03-2.pdf), will reduce the risk of FHB and DON, as long as weather conditions are not highly favorable to FHB and DON during crop flowering and grain fill.

Let me say up front that Folicur is not a "silver bullet" for managing FHB/DON. A great deal of research suggests that about 30% reduction in FHB symptoms and DON accumulation is a reasonable expectation for winter wheat. Sixty percent control or more has been achieved in rare field studies in the United States, but these are atypical results. In other words, do not expect Folicur to provide the same level of FHB/DON control as you have come to expect when fungicides are used to control other wheat diseases. The key is to think in terms of disease suppression, not control. Nevertheless, a 30% reduction in FHB and DON could have a significant economic impact locally, and state-wide, if FHB is moderate in 2004. But be advised that significant losses due to FHB and/or DON are likely even where Folicur has been applied if weather conditions favor severe FHB this spring,

The Section 18 allows for a single ground or aerial application of 4 fl oz/A of Folicur 3.6 F to wheat at full head emergence (Feeke's stage 10.5) to very early flowering (Feeke's stage 10.51). Applications cannot be made before full heading nor within 30 days of harvest. The Folicur Section 18 applies only to wheat and is good for the period April 20, 2004 to May 20, 2004.

Excellent fungicide coverage on wheat heads is crucial to achieve the greatest possible FHB/DON suppression. This is no small challenge since most spray systems used in wheat were developed to deliver pesticides to foliage (horizontal structures). In order to maximize coverage on heads (vertical targets), significant changes may need to be made to the sprayer boom system. Also, discipline must be exercised to ensure that proper sprayer pressure and volumes are used.

For ground application, research has shown that best head coverage is achieved with a double-swivel nozzle configuration of XR8001 flat-fan nozzles oriented forward and backward at a 45 degree angle. Acceptable coverage can also be achieved with a single nozzle configuration using TwinJet TJ8002 nozzles. When using either the double-swivel nozzle or the single TwinJet configuration, best head coverage is achieved when the boom is set 8 to10 inches above the heads, spray pressure is 30 to 40 psi OR 80 to 90 psi, fungicides are delivered in 15 or more gallons or water/A, and ground speed does not exceed 8 mph during application.

For aerial application, nozzles should be angled to direct spray 90 degrees to the direction of travel. Spray droplet size should range from 300 to 400 microns and Folicur should be delivered in no less than 5 gallons of water/A. It is best to spray early in the morning or at other times when heavy dew is present. This will facilitate fungicide coverage on heads.

Regardless of the method of application, be sure to tank mix the lowest rate of a spray surfactant with Folicur to enhance coverage and optimize treatment effectiveness.

As indicated above, Folicur must be applied at a specific time, early flowering, in order to be effective. The optimal time for application is 25% of primary heads, scouted at several random sites in a field, showing anthers (pale, yellow-green structures about 1/8-in-long). Much beyond 25%, and it may be too late. The flip side - applying Folicur before full head emergence/early flowering (which is illegal!) - can also seriously compromise FHB/DON suppression. This brings up a point of tension that many wheat producers may face this spring. Delaying application of Folicur to achieve FHB/DON suppression could allow for excessive build-up of other fungal diseases. Conversely, application of other labeled fungicides before full head emergence will control other diseases, but will have no impact on either FHB or DON. Making both applications, while legal, will be economically difficult to justify. In this case, I would advise growers that foliar disease development should take precedence since little is to be gained by suppressing FHB/DON if serious losses are incurred by allowing fungal diseases to develop.

One desire we all have is for fungicides to be used only when needed. Regular field scouting for foliar fungal diseases has been successfully used by growers for many years to determine if and when to spray fungicides. However, this is not possible with FHB since once symptoms are present it is TOO LATE to spray with Folicur. Below are some general guidelines to help you determine if you should spray Folicur for FHB/DON suppression this spring:

If most or all of the above conditions exist when the crop is at 10-15% flower, you should consider spraying Folicur within one or two days.

An exciting new tool that can be used to help determine the FHB risk is a new web-based, disease forecasting model recently made available by Penn State University, Ohio State University, and the U.S. Wheat and Barley Scab Initiative. This forecasting model, which is reported to be 80% accurate in predicting conditions conducive for FHB epidemics, utilizes real-time weather data from numerous National Weather Service stations within each state. When you enter into the "Risk Map Tool" section of the FHB prediction center home page, you will be asked if you are growing winter or spring wheat and, if winter wheat, whether the field has corn residue that covers 10% or more of the soil surface, regardless of tillage system used. At that point you will come to US map and are asked to click on your state. This will bring you to the main FHB Risk Management Tool page.

The FHB Risk Management Tool page will have a map of Kentucky showing the locations in the state where the weather data are being retrieved. To the upper left corner of the page is a calendar section labeled "Flowering Date". This section needs a bit of explaining. You will note right away that the model will only let you input a "flowering date" as late as the current day. It also covers the preceding 7 days. So, if you estimate your crop will flower on May 7, but it is only May 3, the best you will be able to do is to determine if the weather on May 3 is favorable for FHB, and establish what the FHB risk has been for the preceding 7 days (April 26 to May 2). Of course, since your crop is not flowering, the real FHB risk is zero, no matter what the forecast model says. Nevertheless, that information will tell you if FHB is brewing or not. My advice is to begin determining the FHB risk using this model about 10 days out from crop flowering. Keep checking your wheat and keep checking the model every 1 to 2 days. By the time your crop reaches 10 to15 % bloom, you will have a good feel for the FHB risk in your area. If the forecast model says the FHB risk is high (medium if you are not a risk-taker), and the forecast matches your local weather reality, then you might consider spraying Folicur within 1 to 2 days.

The web address for the FHB Prediction Center is http://www.wheatscab.psu.edu/. Check it out. Once you actually see it and play around with it, what I have said above will make much more sense. The model does have several practical limitations in predicting final FHB levels; these are clearly discussed within the Prediction Center web site. Perhaps the greatest limitation of the model is that it does not account for weather conditions during flowering and grain fill. Disease-favorable weather during these periods can greatly impact final FHB/DON levels. As I said earlier, the forecast model is 80 % accurate, so final FHB/DON conditions will not always be reflected by the model's risk output. The authors of the model discuss this limitation under "Reality Check" in the "Model Details" section of the Prediction Center.

Bayer will begin moving Folicur into Kentucky immediately. In addition, the company will be making available some excellent informational brochures on Folicur and its proper use for suppression of FHB/DON. I have looked over these brochures and find them to be extremely helpful.

We all hope that FHB is non-existent this spring and that growers achieve record yields and grain quality. However, if this is not the case, wheat producers now have an additional tool to consider, and possibly use, to minimize FHB and DON development this Spring. The formal section 18 letter of approval states, "since the emergency condition is dependent on weather favorable to disease development, final approval of the use of Folicur should be determined by the State's expert (s)". That means me or someone I designate for Kentucky. To meet this requirement, I will be closely monitor weather conditions, and also the output of the FHB forecast model, and make appropriate FHB risk declarations in the Kentucky Pest News, as needed.


QUILT FUNGICIDE AVAILABLE FOR USE DURING 2004
By Don Hershman

Wheat
Quilt Fungicide, manufactured by Syngenta, has recently been labeled for use on several crops, including wheat. Quilt is a combination product containing 11.7% propiconazole + 7.0% azoxystrobin. By way of reference, the other syngenta foliar fungicides labeled for wheat, Tilt and Quadris, contain 41.8% propiconzole and 22.9% azoxystrobin, respectively.

Quilt is a broad-spectrum fungicide with some curative properties, but it is best used preventively, before significant infection by fungal pathogens occurs.

Quilt is labeled for use at 7-14 fl. oz./A. Like all products containing propiconazole, including Quilt, Tilt, and the Bayer product, Stratego, Quilt must be applied BEFORE complete flag leaf extension occurs. This use restriction greatly limits the use of ALL propiconazole-based products on wheat in Kentucky. They are excellent fungicides, but cannot be applied when disease control needs are greatest, during mid- to late-head emergence. Flag leaf or earlier applications have been shown to be economical only when early powdery mildew is a problem or the rare times when epidemics of other foliar diseases "kick in" earlier than normal. Nevertheless, almost all research and experience in Kentucky over the past 20 years indicates that flag leaf applications simply do not provide the late-season disease protection needed in most years.

Many states have 24c, special local need, labels that allows later applications of one or more propiconazole-based products. Kentucky does not have a 24c for any product containing propiconazole because, according to our state pesticide regulations, we do not have a special local need. This is because the fungicides Quadris and Headline (a BASF) product can be applied during heading, when fungicide applications are most needed. Both Quadris and Headline can be applied as late as full head emergence, or Feeke's 10.5. However, there is some concern that making applications as late as Feeke's 10.5 may encourage additional accumulation of deoxynivalenol (DON) in harvested grain. I have seen data that both products, when applied just beyond Feeke's 10.5 (i.e., early flowering), sometimes increase DON compared with triazole-based fungicides, such as Tilt or Folicur. However, to my knowledge, there are no data indicating that applying either Quadris or Headline before full head emergence will increase DON. We will be conducting studies this spring to get a better handle on the relationship between timing of application of various fungicides and the impact, if any, on DON accumulation. My working hypothesis is that none of the foliar fungicides currently labeled for wheat will result in increased DON when applied prior to full head emergence, under normal field conditions.

See "Insect Management Recommendations" for more wheat pest information.


Wheat

SMALL GRAINS



CEREAL LEAF BEETLES ARE ACTIVE IN SMALL GRAINS
By Doug Johnson

CLB Cereal leaf beetle (CLB) larvae are out and active. I have only seen adults (emerging from over-wintering) and eggs to date; very little feeding damage was evident. In general these insects do little damage but can be quite a problem, especially if they feed extensively on the Flag and F1 leaves.

The yellow football-shaped eggs usually are found in small groups (2-10 or so). They are attached to the plant tissue with one of the pointy ends. The adults that you might see are the over-wintering survivors and will disappear as egg laying proceeds.

The next stage to appear, and overlapping in time with the eggs, is the larval (juvenile) stage. They look like tiny slugs, are shiny and may be yellow to dark in color. As they increase in size they will begin to glue pieces of leaf material and other trash on their backs as a form of camouflage. They are often described as looking like bird droppings.

As we move through the season adults will appear again. You may see them in mixed populations with the larvae. Adults are 1/2" long shiny black beetles with a red area behind the head and red legs. The adults and larvae do the same type damage.

Damage symptoms are very diagnostic. They eat out the upper surface tissue between leaf veins, leaving the lower surface intact. This feeding produces parallel white streaks in the leaf. The damage is easier to see than the insects. However, the object should be to find the insect before finding many of these white streaks. Especially not many streaks on the Flag and F1 leaves! Feeding on lower leaves is of little interest.

Scout for these insects by examining ten randomly chosen tillers, in ten different locations in the field. This will producer a total of 100 tillers examined. Check all the leaves and stems for cereal leaf beetle eggs, grubs and adults. Note the number of tillers infested the number CLB eggs and the number of CLB grubs and adults. You will need to know if egg hatch is in the early stages or about finished. If you do not find any eggs or if eggs represent less than 50% of the CLB you find, then you don=t need to count again. If however, eggs represent more than 50% of the CLB you find, then you need to sample again in five to seven days. This insect will only have one generation that is important to wheat.

Your wheat will be most susceptible to this insect between Feekes Growth stages 8 and 10.1. The flag and F1 leaves are what need to be protected.

If you are producing very high value wheat (either very high yielding or high quality or wheat carrying a specific trait) you should consider control if on average you find one CLB larva or adult for every four tillers. This threshold is based on work done in North Carolina and Virginia. They generally have a better maturing season then we do, so the threshold is very conservative for Kentucky. Less quality wheat can tolerate higher numbers of CLB, probably closer to 1 CLB per tiller.


Apples

FRUIT



ORIENTAL FRUIT MOTH
By Ric Bessin

Apple Last week there were significant trap catches of Oriental fruit moth in central Kentucky. This insect has become the key pest of apples in some central Kentucky commercial apple orchards. The damage is identical to codling moth and it is very difficult to distinguish the larvae of the two species. Unlike codling moth, this insect can have 6 or more generations per year. In the orchards where this pest has become a problem in the past two seasons, Imidan and Guthion have not been providing effective control, while in other orchards, these sprays have provided excellent control. In these problem orchards, Danitol, Thiodan, Assail, Intrepid, and mating disruption have been working effectively.

Sprays for OFM are applied at 380 degree days past peak flight for a particular generation. The base temperature for OFM is 45F. Degree days are calculated as the number of degrees above 45F for 24 hours. You would subtract 45F from the daily average temperature. If the low temperature is below 45F, then substitute 45F for the low temperature when determining the daily average temperature. When 380 degree days are reached, a spray should be applied for hatching OFM eggs.

This first generation flies during bloom. Growers need to avoid spraying during bloom due to pollination activity or use products such as mating disruption or Intrepid that have little impact on honey bees and other pollinators.

Generally, at petal fall an insecticide is used that will also control plum curculio. Plum curculio becomes active when the low temperature at night begins to exceed 60F. This occurred the past weekend, so growers need to be on the watch for plum curculio and have a petal fall spray ready. Plum curculio can remain active for two to three weeks after petal fall, so occasionally a second spray may be necessary.


Tick

HUMAN/PUBLIC HEALTH PESTS


GETTING PREPARED FOR TICK SEASON
By Lee Townsend and Mike Potter

Tick on Rod Like most creatures, ticks have their favorite haunts and hangouts. They prefer the grasses edges of wooded areas and other overgrown places frequented by small, medium, and large-sized animals that can supply them with a blood meal. Ticks spend a large portion of their life cycle on the ground. When "questing" or looking for a meal, they climb onto low vegetation and catch on to hosts which pass by, including pets and people.

  1. Avoid walking through uncut fields, brush and other areas likely to harbor ticks. When hiking or picnicking in these areas, wear light -colored long pants tucked into socks and consider using tick repellents. Walk in the center of mowed trails to avoid brushing up against vegetation.
  2. Inspect family and pets after being in tick-infested areas, and promptly remove them Ticks often attach at the waist band, under the arms, at the nape of the neck, or in the scalp. Remove attached ticks carefully using a fine-point tweezers. Grasp the tick just behind the point of attachment and pull slowly and steadily until the tick is dislodged. Vaseline, matches and other alternate methods of removal should not be used. Wash the bite area, apply antiseptic and cover with a band-aid.
  3. Keep grass and shrubs in your yard trimmed, and clear overgrown vegetation from edges of your property. Ticks avoid places characterized by direct sunlight and low humidity.
  4. Free-roaming pets are much more likely to become infested with ticks than are those which are confined. Pets may be treated with insecticide dips or sprays, although these products generally lose effectiveness in about a week.
  5. Treating lawns is of little benefit since this is not a preferred habitat for ticks. If insecticides are used, treatment should be concentrated in areas where pets, rodents, and other potential wild hosts of ticks are likely to frequent, e.g., dog house, fenceline, and along margins between wooded or brushy areas and the lawn. Sevin (carbaryl), Bayer Advanced Lawn and Garden Multi-Insect Killer (cyfluthrin) and Ortho Bug B Gon (permethrin) are examples of effective materials. Check insecticide labels for products that contain these active ingredients.


Redbud

SHADE TREES AND ORNAMENTALS



PURCHASING TREES WITH VERTICILLIUM WILT HARMS KENTUCKY NURSERIES
By John Hartman

During recent weeks, Verticillium wilt disease has been discovered in some Kentucky nurseries growing 6 to 8 ft. maple trees supplied only a month before from an out-of- state grower. Many of these infected trees were recently transplanted into Kentucky nurseries and then were uprooted for examination in our plant disease diagnostic lab. Verticillium wilt, which is caused by the fungus Verticillium albo-atrum, is capable of causing a serious vascular wilt of a wide range of woody plants. Several of our common landscape trees such as ash, catalpa, katsura tree, magnolia, maple, redbud, smoketree, and tuliptree are susceptible to Verticillium wilt.

Symptoms. In the recent case, the 'Autumn Blaze' maples were just breaking dormancy when they were examined, but they drew the attention of the growers because some of the young trees were showing symptoms of twig and branch dieback. Cutting into and examining the xylem tissues revealed dark greenish-black streaks of discoloration, particularly in the lower trunk portions of the tree. In some trees, the stained areas included nearly the entire vascular cylinder while in others only a tiny narrow streak may have been present. The staining extended up the trees some distance, but generally did not extend out to the branches and twigs. Some of the healthy-looking trees with no branch or twig dieback were cut into, and these too showed internal xylem staining. Laboratory cultures confirmed the presence of the causal fungus.

Disease biology. The Verticillium fungus survives as resistant, dormant microsclerotia for many years in soil. Thus, soil in some fields of these nurseries may now be contaminated. The fungus infects plant roots through wounds, or in some cases, direct penetration of susceptible root tissue. From the root infections, the fungus spreads into the plant through the xylem. Xylem tissues become blocked so that stems and leaves no longer are supplied with adequate water and mineral elements. After the tree dies, the fungus returns to the soil as tiny resistant fungal microsclerotia. These structures can also be spread by wind, in soil, and on equipment. Many herbaceous and weed hosts are also susceptible so it is hard to avoid contaminated soil. Verticillium wilt is favored by landscape stresses such as wounding and drought. Infected trees provided with good growing conditions only rarely recover from this disease.

Management.


House

HOUSEHOLD



MANAGING CARPENTER BEES
By Mike Potter

Carpenter bee Large, black bees have been hovering around eaves, decks, and wood siding of clients' homes and outbuildings. These are probably carpenter bees searching for mates and nesting sites. Carpenter bees cause cosmetic and structural damage to wood. They can also be quite intimidating and have the potential to inflict painful stings.

The Problem- Carpenter bees are similar in appearance to bumblebees, but have different nesting habits. Bumblebees generally nest in the ground, whereas carpenter bees tunnel into wood to lay their eggs. Bare, unpainted, weathered softwoods are preferred especially redwood, cedar, cypress and pine. Painted or pressure- treated wood is much less susceptible to attack. Common nesting sites include eaves, fascia boards, siding, wooden shake roofs, decks and outdoor furniture.

Carpenter bees overwinter as adults in old nest tunnels. After mating, the fertilized females excavate galleries in wood, laying their eggs within a series of small cells. The cells are provisioned with a ball of pollen on which the larvae feed, emerging as adults in late summer. The entrance hole and tunnels are perfectly round and about the diameter of your finger. Coarse sawdust, the color of fresh cut wood, is often seen beneath the entry hole, and burrowing sounds may be heard within the wood. Female carpenter bees may excavate new tunnels or enlarge and reuse old ones. Serious damage can result when the same piece of wood is worked year after year.

Males are often aggressive, hovering in front of people who are around the nests. The males are harmless, however, since they lack stingers. Female carpenter bees can inflict a painful sting, but seldom will unless handled or molested.

The Solution- The best time to control carpenter bees is before the tunnels are fully excavated. For homeowners, liquid sprays of Sevin or a pyrethroid (e.g., Bayer Advanced™ Home/Lawn & Garden Insect Killer, Spectracide® Triazicide/Bug Stop, Ortho® Home Defense System/Termite & Carpenter Ant Killer) can be applied directly into nest openings, or broadcast sprayed as a deterrent onto wood surfaces attracting large numbers of bees. The broadcast spray approach is often warranted when carpenter bees are riddling siding on a barn, wood shake roofs, decking or similar large expanses of wood. Broadcast treatment is best accomplished with a pump up or hose end sprayer, targeting wood surfaces that are most favored by the bees (fascia boards, joist ends of redwood decks, etc.). Residual effectiveness of such applications is only about 1-3 weeks, so the treatment may need to be repeated. Individual holes which are already present can also be treated with a wasp and hornet aerosol spray or insecticide dust (e.g., Sevin), directed into the nest opening. Although carpenter bees are less aggressive than wasps, female bees provisioning their nests will sting. Consider treating at dusk or while wearing protective clothing.

Leave the holes open for a few days after treatment to allow the bees to contact and distribute the insecticide throughout the nest tunnel. Then plug the entrance hole with a piece of wooden dowel coated with carpenter's glue, wood putty, or other suitable sealant. This will protect against future bees using the old tunnels, as well as moisture intrusion and wood decay.

Carpenter bees normally will not tunnel into painted wood. Therefore a more permanent solution is to paint unfinished wood surfaces, especially those with a history of being attacked. Wood stains and preservatives are less reliable than painting, but may provide some degree of repellence versus bare wood. To further discourage nesting, garages and outbuildings should be kept closed when carpenter bees are actively searching for nesting sites. The annoying flying and nesting habit usually subsides by the end of May.


Microscope

DIAGNOSTIC LAB HIGHLIGHTS


DIAGNOSTIC LAB - HIGHLIGHTS
By Julie Beale and Paul Bachi

Samples diagosed recently included Septoria leaf spot, powdery mildew and barley yellow dwarf virus on wheat; Pythium root rot and Rhizoctonia damping off on tobacco; Pythium blackleg on geranium; cyclamen mite on impatiens; physiological leaf spotting on begonia; iron toxicity on marigold; Pythium root rot and red thread on turfgrass; tip blight on pine; and cedar-apple rust on juniper.


Scout Cat

IPM TRAP COUNTS:


By Patty Lucas, University of Kentucky Research Center

UKREC-Princeton, KY, April 9-16, 2004
Black Cutworm 3
True Armyworm 20

For information on trap counts in southern Illinois visit the Hines Report at - http://www.ipm.uiuc.edu/pubs/hines_report/index.html. The Hines Report is posted weekly by Ron Hines, Senior Research Specialist, at the University of Illinois Dixon Springs Agricultural Center


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.


Lee Townsend
Extension Entomologist

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