WATCH FOR:
By Lee Townsend

• FOREIGN GRAIN BEETLES in homes
• FUNGUS BEETLES in gardens
• HORNWORMS and BUDWORMS on tobacco
• DEFOLIATORS in soybeans, including JAPANESE BEETLES and GRASSHOPPERS.

TOBACCO DISEASE UPDATE
By Kenny Seebold

Blue mold is pretty well established in Kentucky, particularly in the western and central parts of the state. The counties that have confirmed cases of the disease are: Breckinridge, Clinton, Daviess, Grant, Harrison, Hardin, and Fayette. We've also got quite a bit in Tennessee and North Carolina. The good thing is that the hot and dry weather has kept the outbreaks in check and limited the need for fungicides to those in the immediate vicinity of the outbreaks. As you know, hot sunny days and night-time temperatures above 70F severely reduce reproduction and spread of the blue mold pathogen.

A recent cold front has pushed night temperatures into the range that blue mold favors, and these temperatures will stay in the mid-60's through the next 10 days or so. This elevates the blue mold risk somewhat, but hot and sunny days should keep the disease in check. The long-range forecast calls for increased rain chances around August 5. At this point we could see the risk of blue mold development increase. Growers in creek and river bottoms, or other areas where dew and fog are heavy, could face more of a risk, as will those close to the known sources of blue mold in KY. For those in higher-risk situations, application of Actigard, or Dithane + Acrobat may be warranted. Both programs offer the advantage of having a systemic fungicide in the mix.

We've also seen quite a bit of frog eye and target spot around the Commonwealth, but levels are not low enough to warrant an application of Quadris in the majority of cases. As we head into the end of the season, if you've got a grower who has 5% damage or higher of either disease, he may want to consider an application of Quadris at 8 oz/A. This will give excellent suppression of these diseases and will offer protection against blue mold as well (an advantage that Quadris has over the other fungicides we can use on tobacco). If frog eye and target spot are not of concern, growers should consider going with Acrobat + Dithane or Actigard.

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

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

WATCH FOR SPIDER MITES IN SOYBEANS
By Doug Johnson

Several of the states north of us are reporting spider mites in soybeans. Most of the infestations are not large but the mere presence of this pest bears watching. I have seen NO evidence of spider mites in KY soybeans but the weather is certainly right.

In KY spider mites tend to be found under drought conditions, which most often include high temperatures as well as lack of rain. This season we have had two time periods of deficient rain, with only the remnants of hurricane Dennis as relief. Whether or not this weather pattern is enough for spider mites to become a problem is unknown but it certainly bears watching.

Why do we see these creatures only under drought conditions? My colleagues, Mike Gray and Kevin Steffey, from the Univ. of IL. have put together a nice outline of probable reasons: "Several interacting factors help explain why densities of two spotted spider mites increase during hot, dry weather:

• Drought provides a more favorable thermal environment for the mites' growth and development.
• Drought-stressed plants are more attractive to and acceptable for the mites.
• Drought-stressed plants are physiologically more suitable for the mites.
• Drought conditions do not favor natural enemies and pathogens of spider mites.
• Drought might induce genetic changes in the mites".

The pest is relatively rare, but when they do occur they are often hard to combat. Generally the first indication is a patchy yellowing of fields, often along borders and in weedy areas. At first the yellow will be a bright clear color but will soon turn to a "bronze" or "orangish" look. This color is produced when the mites feed on the plants cells in the leaves. While feeding they remove the cell contents and thus the green color. This is not the light yellow associated with poor nitrogen, but a deep yellow brown. If you see this type of symptom shake some leaves over a white piece of paper or shake cloth, if mites are causing the problem then the paper will be covered with tiny but moving dots. You may also see a great deal of trash on the undersides of leaves and if the populations are large you may find silk connecting leaves.

If a mite infestation is present, take a close look at the weather. Generally a good rainfall will correct the situation. If that is not likely, examine the plants assuming the deeply bronzed areas of the leaves were eaten. Use the defoliation tables in ENT-13 to make a control decision.

Even in drought stricken areas mites will be very unevenly distributed. One field or one area of a field may have them, while another is completely clear. Spot or border treatments are often used because of this scattered distribution. If you use a partial treatment be sure to make one more passes outside the area exhibiting symptoms. The mites will certainly have spread into areas that do not yet exhibit symptoms.

There are at present, few insecticides registered for control of spider mites. Check ENT-13 for registered products and use rates.

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

WEST NILE IN KENTUCKY
By Lee Townsend

According to the Cabinet for Health and Family Services, Department of Public Health website (July 20, 2005), there has been one case of West Nile virus in a horse in Monroe County and one bird case in Lewis County.

The main strategies for protection are use of repellents when outdoors during times when mosquitoes are active, exclusion of mosquitoes in homes by window and door screens, and elimination of breeding sites, especially collections of stagnant water.

DEET has been the standard for mosquito repellents for about 50 years and is still recognized as providing effective, long term protection against mosquitoes and many other blood-feeding arthropods. It is available in a wide range of products with varying concentrations of the active ingredient. However, some object to the odor of DEET or the oily feeling that it leaves on the skin. There also are concerns about applications to children.

The CDC (Centers for Disease Control) has announced the addition of picaridin and oil of lemon eucalyptus as effective repellents. They have been shown to provide protection comparable to products containing 10% DEET.

Reduction or elimination of breeding sites is the foundation on which mosquito control programs are based. It is impractical or impossible to do a complete job so treatment of some active or potential mosquito production areas is desirable. This is done with products called larvicides. Larvicides are insecticides which are used to control immature mosquitoes, also called wrigglers. Larvicides are applied directly to standing water as pellets, briquets, or surface sprays.

There is basically one larvicide option for the general public. Several companies sell products with names such as Mosquito Dunks or Quick Kill Mosquito Granules. The active ingredient is a toxin produced by the soil bacterium Bacillus thuringiensis israelensis (Bti). Bti, registered as an insecticide in 1983, is specific for mosquito larvae and immature stages of related flies. The larvae ingest small particles of the formulation and the insecticide works at sites that are not present in mammals. Bti is essentially non- toxic to humans and mammals when used according to label instructions. The larvae starve over a period of time so the visual impact of an application is not obvious. As with Bt insecticides used for caterpillar control, Bti works better against small larvae, it does not kill the tumbler (pupal) or adult stages of mosquitoes.

Mosquito Dunks often are sold in packs of 6 for $9 to $12 at hardware and discount stores. One dunk is recommended per 100 square feet of water surface. The dunk breaks down slowly when wet and will release the active ingredient over about a 30 day period. The Mosquito Quick Kill products (about $0.75 per ounce) are a granular formulations that begin to release the Bti toxin more quickly and over a larger area, resulting in faster action. While results come more quickly, the residual life of the treatment is generally not as long as the dunk formulation.

Local, state, and federal agencies can use Bti larvicides and those containing the insect growth regulator methoprene (Altosid). These larvicides are sold through outlets catering to commercial applicators, mosquito control agencies, and pest control companies. These groups also have access to monomolecular films, chemicals that spread a thin layer over the surface of water, which interfere with breathing of mosquito larvae and pupae which are dependent on atmospheric oxygen. These films are applied only to standing water and do not last very long.

In any given year there are many potential breeding sites for mosquitoes and natural events can contribute more. For example, trees uprooted by storms can leave holes to collect seepage water or some of the abundant rainfall we have had this spring. Hundreds of mosquitoes can develop in these areas in a short period of time. In addition, there is concern about ornamental pools, stock ponds, and many other sites. Identification of these sites can help to target places where physical or insecticidal control methods would be justified and also keep unnecessary applications from being made where mosquito larvae are not present.

With a little careful observation it is fairly easy to see mosquito larvae in clear, shallow water over light colored bottoms. They are harder to see in dark, stagnant water where there is a lot of debris or vegetation. Also, avoid casting a shadow over the water, mosquito larvae and pupae will dive in response to light changes. They also can be captured by quickly plunging a long-handled dipper into the water.

STINK BUG DAMAGE TO PEPPERS COMMON
By Ric Bessin

There has been an unusually high levels of stink bug damage to pepper fruit. Stink bug damage to pepper is very similar to that on tomato. Stink bug feeding causes a light colored corky area just underneath the skin of the fruit. These damaged areas are visible through the skin.

Generally, stink bug numbers and their damage on various crops are up this year across the state. Damage was common early in the season on corn. The same species of stink bugs, the brown and green stink bugs, attack peppers, with the brown being more difficult to control. There has also been similar reports of stink bug damage to tomatoes. Stink bug damage to tomatoes picked in the breaker stage is not readily discernable.

Adult stink bugs migrate from weedy areas into pepper fields, particularly when the weedy plants begin to decline. Continual weed management throughout the season around fields helps to reduce stink bug immigration into fields. In terms of insecticidal control, endosulfan (Thiodan, Phaser) and the pyrethroid insecticides (Ambush, Asana, Baythroid, Pounce) are the most effective insecticides registered for peppers against stink bugs, but they provide only fair to good control of stink bugs. When scouting peppers for stink bugs and their damage in order to make control decisions, keep in mind that the presence of fruit damage does not mean that stink bugs are necessarily still active.

SPIDER MITES ON VEGETABLE CROPS
By Ric Bessin

High temperature and low humidity are two of the key ingredients needed to cause an outbreak of spider mites on many fruit and vegetable crops. Tomatoes, beans, muskmelons, water-melons, sweet corn and apples are very susceptible to spider mites. Extended periods of hot, dry weather as we have had over the last three weeks favor mite buildup. Infestations usually first occur at the edge of a field, typically near rank weed growth or dirt roads. Generally mites feed on the undersides of leaves. They use their sucking mouthparts to remove sap from plants, giving the upper leaf surface a speckled or mottled appearance. Leaves of mite infested plants may turn yellow and dry up, and plants may lose vigor and die when infestations are severe. The undersides of affected leaves appear tan or yellow and have a crusty texture. Heavy infestations of the two-spotted spider mite produce fine webbing which may cover the entire plant. Mites can be identified by shaking symptomatic leaves onto a sheet of white paper or by observing infected leaf areas with a hand lens. In hot dry weather, mites can cause plants to drop leaves in a few weeks. Fruit from severely infested plants are often unmarketable because defoliated plants tend to yield small, poor quality fruit.

Destruction of weeds adjacent to and in fields should be done in the fall or early spring. Growers should manage weeds around fields carefully during the season. Grass should be mowed regularly. Spraying or mowing of weeds after growth has become rank may increase the movement of mites to cultivated plants. Use of overhead-sprinkler irrigation may provide some short-term relief of mite infestations.

Miticides are available for some vegetable crops but should be used only where justified. As with aphids, mark infestations with flags, and check them again every 3 or 4 days. Mites can easily be moved to infested plants on clothing, so always examine infested areas last during inspections. Because mites usually occur on the undersides of leaves, applications of contact miticides need to be directed at both the lower and upper leaf surfaces. Mite eggs are resistant to most miticides, so repeated applications are often necessary to control infestations. Two applications spaced 5 to 7 days apart may be necessary.

HOSTA CROWN ROT
By John Hartman

Hosta plantings are popular in Kentucky landscapes because the plants come in a variety of colors and forms, are easy to grow, thrive in shady locations, and are generally pest-free. During prolonged periods hot, humid summer weather, however, crown rot disease, or southern stem blight caused by the fungus Sclerotium rolfsii, can be devastating to Hosta.

Symptoms. The first indication of trouble is when lower leaves begin to turn yellow, then show marginal scorch and browning. These symptoms often progress to the upper foliage, and when pulled, affected leaves easily come loose from the plant. A soft, brown, mushy decay may be seen at the base of the petiole. Often-times, a coating of white fungal threads or fungal mycelium is present on the rotted petiole or on the ground at the base of the diseased plant. Tiny spherical sclerotia, about the size of mustard seeds are sometimes attached to the fungal threads or are scattered or in clusters on the ground under the plant. Sclerotia may be white, tan, orange, or reddish brown, and are the structures that allow the fungus to survive for long periods in the soil.

The life of S. rolfsii. Sclerotia of the fungus germinate during warm, humid weather and fungal mycelium grows along the ground until it encounters a susceptible plant nearby. The fungus attacks the lower leaf petioles with plant tissue degrading enzymes and toxins, causing the petioles to rot. Hosta leaves with rotted petioles soon turn yellow, then brown, and collapse. Fungal sclerotia live in the soil for many years waiting for an opportunity to attack new plants. The fungus can be spread in the garden when sclerotia are carried on tools, on shoes, and in soil; the fungus can be moved long distances on transplants and nursery stock.

In Kentucky gardens S. rolfsii is likely to attack:

• Herbaceous perennials such as ajuga, anemone, aster, bleeding heart, caladium, chrysanthemum, columbine, coreopsis, daffodil, dahlia, daylily, delphinium, dianthus, foxglove, hibiscus, hosta, hydrangea, iris, lily, lily-of-the-valley, liriope, pansy, peony, periwinkle, phlox, tulip, and even wild violets.
• Annual flowers such as ageratum, begonia, cosmos, impatiens, marigold, nasturtium, petunia, and zinnia.
• Vegetables such as beans, peppers, and tomatoes.
• Woody nursery seedlings of apple, arborvitae, catalpa, dogwood, forsythia, prunus, rose, and walnut.

• Purchase only healthy perennials, looking especially for causes of yellowing or browning of lower leaves.
• Avoid moving plants from contaminated beds to other parts of the garden.
• Use effective garden sanitation practices such as digging up and destroying diseased plants and surrounding soil and thoroughly washing contaminated soil from tools. Although drastic, carefully digging and removing contaminated garden bed soil to a depth of 8 inches and replacing it with non-contaminated soil can be effective.
• Research done at Iowa State University suggests that a mulch-free zone of several inches at the base of susceptible plants might help. They also found less disease in plots mulched with pine needles compared to pine chunk bark or hardwood mulches.
• Grow plants not known to be hosts of S. rolfsii such as bluebells, coral bells, cranesbill geranium, English ivy, forget-me-not, hellebore, lady's mantle, lamb's ear, Pachysandra, poppy, primrose, Solomon's seal, spiderwort, and Trillium.
• Hosta cultivars differ in susceptibility to crown rot caused by S. rolfsii. In a 2-year evaluation of selected cultivars done at Iowa State University:
  • The five most tolerant (susceptible, but least damaged) Hosta cultivars were 'Halcyon,' 'Zounds,' 'Honeybells,' 'Snow Mountain,' and 'Tall Twister.'
  • The five most susceptible cultivars were 'Lemon Lime,' 'Munchkin,' 'Nakaiana,' 'Platinum Tiara,' and 'Tardiflora.'
  • Intermediate susceptible cultivars in decreasing order of susceptibility included 'Serendipity,' 'Pee Dee Goldflash,' 'Floradora,' 'Harmony,' 'Pearl Lakes,' 'Vera Verde,' 'Gold Drop,' and 'Tokudama.'
  • All of these 18 cultivars are susceptible to some degree. Most Hosta cultivars have never been tested for crown rot susceptibility, but it is likely that most of them are also susceptible.

FOREIGN GRAIN BEETLES - COMMON IN NEWER HOMES
By Mike Potter

The foreign grain beetle is a common pest in Kentucky from late July through September and can be found in tremendous numbers inside buildings. The small (about 1/16-inch long) reddish brown beetles frequently pose temporary problems in new houses (up to about 4 years old) or where there has been remodeling. They belong to the "fungus beetle" group; larvae live in wall voids and feed on the molds and fungi that grow on poorly seasoned lumber or wet plaster and wall board. When new homes are built, damp wood is often covered with molds or mildew which attracts the beetles. The beetles may also be attracted to accumulations of sawdust which often occur behind walls as a byproduct of construction. Eggs are laid on this food material and the larvae develop on the surface fungi. The adults usually become a problem in late summer when they move out of wall voids and are attracted to windows and lights. Foreign grain beetles can also be associated with plumbing leaks, condensation problems, or poor ventilation. Occasionally, the source is stored products, grains, meal, etc. that are moldy or in poor condition.

Control is best accomplished by drying out the wood and/or eliminating the moisture source. Most new homes dry out naturally within the first few years, and the fungi and molds disappear along with the beetles. Drying time can be enhanced by increasing ventilation, e.g., by use of fans and air conditioning. Rapid relief can be obtained with directed applications of aerosol sprays containing pyrethrins, but such treatments must be applied frequently. A vacuum cleaner works just as well in terms of removing any visible beetles which are present. More permanent control can be achieved by locating the infested wall areas or source of dampness (usually next to where the beetles are most abundant) and injecting residual aerosols or dusts into cracks and crevices along baseboards and into the wall voids.

If the homeowner can tolerate the beetles during the period when they are most active (late summer) the problem will usually resolve itself. Some comfort can be taken in the fact that foreign grain beetles are only a nuisance by their presence, i.e., they do not bite or damage wood, fabric or stored food in sound condition.

By Patty Lucas, University of Kentucky Research Center

View Princeton trap counts for the entire 2005 season at - http://www.uky.edu/Ag/IPMPrinceton/Counts/2005trapsfp.htm

Fulton County trap counts are available at -http://ces.ca.uky.edu/fulton/anr/Insect%20Counts.htm

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

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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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