DISEASE CONTROL ISSUES AT TOPPING TIME
By Kenny Seebold

During the week of August 1, blue mold was confirmed in five additional counties: Adair, Barren, Larue, Monroe, and Owsley. That brings the total to 12 counties with blue mold in the Commonwealth. The long-range weather forecast, which last week had called for increased chances of rain and cooler temperatures, has been revised and indicates that we will continue with hot, dry days and warm nights. This should limit the spread of blue mold across the state during the week of August 8. Those growers near known sources of blue mold, or who have received rain recently, should check their fields for the presence of blue mold and make fungicide applications if needed. Growers should also be on the lookout for diseases such as target spot and frogeye leaf spot, which have been reported to be fairly active in some parts of the state.

Disease control options begin to thin-out as we get later in the season, and a good bit of the tobacco out there is close to topping or has been topped. We need to remember that some of the fungicides that we use have pre-harvest restrictions that must be observed to ensure that chemical residues are not present on the crop:

Dithane - do not apply to burley and other types within 30 days of harvest.

Actigard - do not apply to burley or dark tobacco within 21 days of harvest.

Acrobat - preharvest interval is 0 days, but must be tank-mixed with Dithane; therefore it should not be applied within 30 days of harvest because of the pre-harvest restriction for Dithane.

Quadris - only one application (out of 4 total for the season) can be applied in the last 30 days before harvest, but can be applied up to the day of harvest for target spot and frogeye.

As the crop matures, we can expect susceptibility to blue mold to taper-off, and hot daytime temperatures should help keep the disease from exploding over a wide area in a short time. We still need, though, to keep an eye on the weather and take precautions where needed. Also, please let us know if you have seen blue mold and have not yet reported it. Feel free to contact me with any questions.

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".

RUST: NO; SUDDEN DEATH SYNDROME: YES
By Donald Hershman

As of August 4th, there is no confirmed soybean rust anywhere near KY. However, the UK Plant Disease Diagnostic Lab at Princeton has received numerous samples of soybean sudden death syndrome (SDS). I have also gotten about a dozen phone calls recently and I saw a report today where the disease is developing very significantly in some fields in Southern Illinois. Point is, it looks like SDS may be a significant player this year.

By way of background, SDS is a root disease caused by the fungal pathogen, Fusarium solani f.sp. glycines. The roots of plants are infected and become diseased during the vegetative stages of plant development. Then, typically as plants enter the pod development stages, foliar symptoms are expressed as a result of foliar sensitivity to one or more plant toxins produced by the fungus in diseased root tissue. In extreme cases, plants can die prematurely with yields being dramatically impacted. In some years (like 2004) plants will show symptoms early and later recover, with no impact on crop yield. In most years the response is somewhere in the middle of these two extremes.

SDS is characterized by a rotting of the primary and secondary root system, a subtle brown discoloration of the stem tissue immediately inside the green exterior, and leaf symptoms that start as yellow spots and blotches between the veins of upper leaves (usually), leading to large areas of brown tissue between the veins, and eventual defoliation of the leaflets, but not the petioles. Abortion of flowers and young pods is common. Symptoms usually first develop in hot spots in fields of varying shapes and sizes. Entire fields may eventually become involved in severe instances, but even then, there are typically areas in fields where the disease is more severe than in others.

At this time, there is nothing that can be done to make the disease less or more serious. The die is cast, as it were. SDS is in a race against time with the crop. If the crop reaches the R5-R6 stage before the disease is severe, then the yield prognosis will be excellent. Serious disease prior to the R5 stage, however, can result in serious yield reductions. Typically the earlier the onset of serious SDS, the greater the impact will be on crop yield.

Initially I was surprised we are seeing so much SDS, considering the predominately dry conditions we have had in June and July. Then I recalled the cool conditions that lingered in April and early May, and the fact that many growers planted earlier than normal in an attempt to escape soybean rust. Both the cooler soils and early planting dates may have resulted in more root infection by the SDS pathogen than is "normal". Then, the later season moisture stress conditions probably encouraged foliar symptom expression of SDS.

As I said, there is nothing one can do now to ameliorate the effects of SDS; the disease will have to run its course. However, the disease can be drastically reduced next season by planting a resistant variety coupled with avoiding late-April and early-May planting dates.

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

FRUIT INSECTICIDE/MITICIDE UPDATE
By Ric Bessin

There have been several new insecticides and miticides that have been labeled for use in some fruit crops since the release of ID-92 (Commercial Tree Fruit Spray Guide 2005) and ID-94 (Commercial Small Fruit and Grape Spray Guide).

Actara (thiamethoxam) has been labeled for blueberry and strawberry and has a 3 day PHI for those crops and a 12 hour REI. This is a group 4A insecticide that control aphids and leafhoppers on blueberry and aphids and whiteflies on strawberry. Actara has also been labeled for apples (east of the Mississippi River) and stone fruit (peaches, cheery, and plum). The PHI for apples is 14 or 35 days depending on rate and 14 days for stone fruit. It controls aphid, leafminers, leafhoppers, and plum curculio on apples and aphids, plum curculio, stink bugs, leafhoppers, tarnished plant bug, and cherry fruit fly on stone fruit.

Clutch (thiamethoxam) has been labeled for apples and pears and has a 7 day PHI (pre-harvest interval) for both of those crops and a 12 hour REI (re-entry interval). This is a group 4A insecticide that is labeled for control of aphids, leafhoppers, plum curculio, apple maggot, codling moth, leafminers, and Oriental fruit moth.

Decis (deltamethrin) has been labeled for apples and pears and has a 21 day PHI for both crops and a 12 hour REI. This is a group 3 insecticide that is labeled for control of leafminers, leafrollers, codling moth, apple maggot, plum curculio, green fruitworm, scale crawlers, Oriental fruit moth, and stink bugs. Decis is a restricted use insecticide (RUP).

GF-120 NF Naturalyte (Spinosad) has been labeled for use on pome fruits, stone fruits, and blueberries and has a 4 hour REI. GF-120 NF Naturalyte controls various fruit flies including apple maggot and cherry fruit fly. It is OMRI certified, approved for use in organic production systems.

Kanemite (acequinocyl) has been labeled for apples, pears, and strawberries and has a 1 day PHI for all three crops and a 12 hour REI. It is a miticide that is labeled to control two-spotted spider mite and European red mite.

Onager (hexythiazox) has been labeled for peaches, plums, nectarines, cherries, and non-bearing tree fruits and vines. On stone fruits the PHI is 28 days. Onager is a miticide labeled for control of two-spotted spider mite and European red mite. On other tree fruits and vines it may not be used the same season those crops are to be harvested.

ARMILLARIA ROOT ROT
By John Hartman

The moderate drought that is currently afflicting the Bluegrass region of Kentucky is placing enormous stress on landscape trees. Drought can influence susceptibility of trees to root and butt rot caused by the fungus Armillaria mellea. Some of our most valuable shade and ornamental trees are susceptible to Armillaria root rot disease. This disease is also called shoestring root rot disease because of fungal rhizomorphs closely resembling shoestrings produced by the fungus underneath infected bark, over infected roots, or in the soil. Among shade and ornamental trees, oaks and maples appear to be the most commonly infected, although the disease is occasionally destructive on a wide range of other woody plants. It is likely that the disease may occur on almost any tree or shrub grown, if the necessary conditions for infection are present. The disease is associated with trees previously in poor vigor, usually caused by winter injury, drought, or even construction damage.

Symptoms. The aboveground symptoms cannot be differentiated from those produced by many other diseases or agents that cause root or trunk injuries. Probably the most striking external symptom is a decline in vigor of a part or the entire top of the tree. Where the progress of the disease is slow, branches die back from time to time over a period of several years.

Signs. Clearly identifiable signs of the fungus causing this disease are found at the base of the trunk at or just below the soil line or in the main roots in the vicinity of the root collar.

• Fan-shaped, white wefts of fungal tissue closely appressed to the sapwood are visible when the bark is cut away or lifted. Scraping or lifting the white wefts of mycelium, which have a strong mushroom odor, will reveal water-soaked sapwood. Where the entire top has wilted and died back, the fungal tissue will be found completely around the trunk. Where a large branch has died back, or only one side of the tree shows poor vigor, the fungus will be found on one or two main roots or on one side of the trunk base.
• Where the tree has been dead for some time, dark brown to black "shoestrings," also called rhizomorphs, may occur beneath the bark or in the soil near the infected parts.
• Clusters of light brown mushrooms, called honey mushrooms, may appear in the vicinity of the rotted wood in late autumn. In landscape circumstances, infected trees are often removed before the mushrooms have a chance to form.

Disease management. Armillaria root rot is very difficult to control.

• Provide good growing conditions for the tree. Pay attention to the need for additional water during drought.
• An infected tree whose entire root system or trunk is diseased cannot be saved.
• When the tree dies, the large roots in the vicinity of the trunk as well as the trunk itself should be removed and destroyed. Soil in the immediate vicinity should also be removed.
• Avoid replanting the same species as the one removed. Oaks, maples, and other highly susceptible species should be avoided.
• The following trees are thought to be less susceptible to Armillaria root rot except when growing under extremely stressful conditions: Bald cypress, boxwood, callery pear, catalpa, Chinese elm, cork tree, crabapple, gingko, hackberry, holly, honey locust, Japanese maple, magnolia, mulberry, pine, smoke tree, sumac, sweetgum, sycamore, tree-of-heaven, tuliptree, white fir.

SPIDER WARS
By Mike Potter

Numerous calls are received this time of year about spiders. Typically, the caller wants to know if the spider they've seen is dangerous, and what ? if anything ? should be done in terms of control. Many different kinds of spiders live in and around buildings. Some, such as the house, cellar, and garden spiders, construct webs to help entrap their prey. Others, like the wolf spider, roam freely and make no webs. The vast majority of spiders are harmless and in fact beneficial because they prey upon flies, crickets and other insects. They generally will not attempt to bite humans unless held or accidentally trapped against the skin. Most spiders have fangs too small or weak to puncture human skin. Of the hundreds of species found in Kentucky, only the black widow and brown recluse are dangerous. Fortunately, both are relatively uncommon, and have markings that can be used to distinguish them from other non-threatening species.

Although most spiders are harmless, few people are willing to tolerate them inside the home. Their unsightly webbing and fecal spots outweigh the beneficial aspects of spiders to most homeowners. This column provides practical tips on spider control for concerned clients.

General Control Measures (all species)
1. Routine, thorough house cleaning is the most effective way to eliminate spiders and discourage their return. A vacuum and broom are the householder's most useful tools for removing spiders, webs, and egg sacs. Egg sacs in particular should be removed since each may yield hundreds of new spiders.

2. Spiders prefer quiet, undisturbed areas such as closets, garages, basements, and attics. Reducing clutter in these areas makes them less attractive to spiders.

3. Large numbers of spiders often congregate outdoors around the perimeter of buildings. Moving firewood, scrap lumber, and debris away from the foundation can reduce migration indoors. Shrubs, vines and tree limbs should be clipped back from the side of the building. Maintaining a vegetation-free zone next to the house also lowers the moisture content of the foundation and siding, making them less attractive to termites, carpenter ants, rodents and decay.

4. Install tight-fitting window screens and door sweeps to exclude spiders and other insects. Inspect and clean behind window shutters, and inside the orifices of gas barbecue grills.

5. Consider installing yellow or sodium vapor light bulbs at outside entrances. These lights are less attractive than incandescent bulbs to night-flying insects, which, in turn, attract spiders.

6. To further limit spider entry from outdoors, insecticides can be applied as a "barrier treatment" around the base of the foundation. Pyrethroid insecticides (e.g., Spectracide Triazicide (lambda cyhalothrin), Bayer Advanced Multi-Insect Killer (cyfluthrin), Ortho Home Defense Max (bifenthrin)) are quite effective, but may need to be reapplied periodically throughout the summer. Pay particular attention to door thresholds, garage and crawl space entrances, and foundation vents.

Brown Recluse/Black Widow
Both of these spiders are potential health threats. Most bites occur while putting on a shoe or piece of clothing where a spider has hidden, or while sorting through boxes, clutter, etc.

The female black widow is about 1/2-inch long, shiny black and usually has a red hourglass mark on the underside of the abdomen. In juvenile spiders, the hourglass mark may be reduced to two separate spots. Most adult brown recluse spiders are about the size of a dime to a quarter with legs extended. Coloration ranges from tan to dark brown, and the abdomen and legs are uniformly colored with no stripes or mottling. For laypersons, the most distinguishing feature of a brown recluse is a dark violin-shaped mark on its back, with the neck of the violin pointing toward the rear (abdomen) of the spider. Closer examination under magnification will reveal only three pairs of eyes toward the front of the head - most other spiders have eight eyes. Although both the black widow and brown recluse have distinctive markings, a "spider is a spider" to most people. Concerned homeowners or victims of spider bites should be advised to bring the specimen in for confirmation.

Spider bites are difficult to diagnose, even by physicians. Black widow venom is a nerve toxin and its effects are rapid. The victim suffers painful rigidity of the abdomen and usually tightness of the chest. Victims should seek medical attention promptly. The bite of the brown recluse is usually painless until 3 to 8 hours later when it may become red, swollen and tender. Later the area around the bite site may develop into an ulcerous sore from ½ to 10 inches in diameter. Healing often requires a month or longer, and the victim may be left with a deep scar. Prompt medical attention can reduce the extent of ulceration and further complications. Not all brown recluse bites result in ulcerations and scarring.

The brown recluse may be found living indoors or outdoors. Black widows are more often encountered outdoors. Thorough inspection of cracks, corners, and other dark, undisturbed areas with a bright flashlight is an essential first step in determining the location and extent of infestation. Indoors, pay particular attention to basements, attics, crawl spaces, closets, under/behind beds and furniture, inside shoes, boxes of stored items, and between hanging clothing. Brown recluse spiders also may be found living above suspended ceilings, behind baseboards, and inside ductwork or floor/ceiling registers. Another way to detect infestations in these areas is to install several glue boards or sticky traps. Designed to capture mice and cockroaches, these devices can be purchased at grocery or farm supply stores. Placed flush along walls and in corners, they are useful monitoring tools and capture large numbers of spiders.

Brown recluse and black widow spiders also live outdoors in barns, utility sheds, woodpiles, and underneath lumber, rocks, and accumulated debris. To avoid being bitten, wear work gloves when inspecting inside boxes or moving stored items.

Each of the management tips (1-6) mentioned above for spiders in general are useful for the black widow and brown recluse. Removal of unnecessary clutter is especially helpful in making areas unattractive to these pests. Indoor infestations of brown recluse and black widow also warrant treatment with insecticides. Application should be directed into areas where spiders are living, contacting as many spiders and webs as possible.

Infestations of brown recluse or black widow spiders often require specialized skills, persistence and equipment to eradicate. Because these spiders are potential health threats, it is often prudent to call a professional.

For detailed information about brown recluse spiders, consult the newly revised publication on the entomology department web site.

DIAGNOSTIC LAB - HIGHLIGHTS
By Julie Beale and Paul Bachi

Recent samples in the Diagnostic Laboratory have included pollination problems on corn; potato leaf hopper burn and Lepto leaf spot on alfalfa; downy mildew, thrips injury, potassium deficiency, manganese deficiency and sudden death syndrome on soybean; angular leaf spot, black shank, blue mold, brown spot, tomato spotted wilt virus, tobacco mosaic virus, alfalfa mosaic virus, tobacco streak virus, ozone injury, frenching, Fusarium wilt and frogeye leaf spot on tobacco.

On fruit and vegetable samples, we have diagnosed downy mildew on grape; Botryosphaeria canker on blueberry; angular leaf spot, anthracnose, and Pythium root rot on bean; Pythium stalk rot and smut on sweet corn; anthracnose on cucumber; pitted scab on potato; Septoria leaf spot, early blight, blossom end rot, Phoma leaf spot and Fusarium wilt on tomato.

On ornamentals and turf, we have seen bacterial leaf spot, Pythium root rot and nutritional problems from both high and low pH on chrysanthemum; Rhizoctonia root rot on celosia, impatiens, speedwell and vinca; anthracnose on ash; powdery mildew on dogwood; Sphaeropsis tip blight on pine; Gloeosporium leaf spot on elm; Hypoxylon canker on maple; summer patch and Curvularia blight on bluegrass and brown patch on fescue.

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.

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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