Kentucky Pest News Newsletter


Number 1026__________June 21, 2004




By Ric Bessin

Corn rootworm beetle Western and Northern corn rootworm beetles are now emerging from corn. While these are usually only an economic problem in continuous corn in Kentucky, growers need to monitor their fields this summer in order to make control decisions for next year. Although corn rootworm adults will strip the upper leaf surface during the summer, this damage is minimal and does not usually require any controls.

The adult Western corn rootworm is the most common and is a 1/4 inch green leaf beetle with a few black markings. During the next four to six weeks, the adults will continue to emerge, mate and lay eggs. In fields where the average number of adults is equal to or exceeds one beetle per plant, growers will need to manage corn rootworm in 2005. Options for rootworm control include; crop rotation, soil insecticides (granular or liquid), seed treatments, or use of Bt rootworm corn. First year corn in Kentucky generally does not need to be treated for corn rootworm.

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



By Doug Johnson

Soybean aphid NEW WEBPAGES
If you are interested in a wide variety of information concerning the soybean aphid you are invited to view the NEW KY-IPM Soybean Aphid web-pages. Go to the KY- IPM home page at:
Then click on the Soybean Aphid icon near the bottom of the page.

Currently, these pages contain the expected outlook for Kentucky in 2004, regional and national information, and links to sites concerning this new pest. I anticipate adding additional information sources as time permits.

These pages and Kentucky Pest News will remain one of the first locations that new soybean aphid information will be posted.

My appreciation is extended to Ms. Patty Lucas and Dr. Pat Dillon for getting this new information site up and running.

Illinois has not reported a population of soybean aphids…yet! However, Michigan, Wisconsin and Iowa have reported small populations. Illinois's situation is probably the best predictor of the presence of soybean aphid for the major concentration of Kentucky's production.

Beware, in Iowa the first report of soybean aphid in 2004 was originally reported as thrips. Like aphids, thrips are small insects. However, they inflict their damage with a rasping mouth part. The surface tissue of the leaf is removed leaving a lighter (at first) colored area, usually in tiny streaks. In Kentucky thrips have also been associated with "cupping" of soybean leaves. In 2003 my first suspected soybean aphid field turn out to be thrips. These insects are very common and will be found in all Kentucky soybean fields. However, they rarely cause damage.

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




By Paul Vincelli

Red clover Although red clover and red clover/grass hays are very suitable forages for many circumstances, red clover hay has occasionally been refused by livestock. This is not a new problem, but it is one for which the cause is still not understood. When it occurs, it typically is a problem in second or third cutting hay. There are many possibilities as to the cause, including chemical changes that make the hay unpalatable. One possible cause that has attracted my attention is the presence of a fungus on the leaves and stems of red clover that was refused by livestock.

The fungus is called Rhizoctonia leguminicola. This fungus causes the red clover disease called "Black Patch". Black patch produces brown to gray-black leaf spots which often have a "target-spot" appearance. Leaves and stems eventually become blighted, turning dark brown. The disease occurs only during warm, muggy weather in second or later cuttings that go beyond full bloom. Diseased forage contains the chemicals slaframine and swainsonine, which are toxic to livestock. Black patch on red clover is known to cause "Slobbers", where horses and cattle that consume the hay slobber abundantly, producing clear, viscous saliva for days.

Is the black patch fungus also responsible for feed refusal? This has not been determined as of yet. However, this question is "researchable", meaning that we can attempt to answer the question by initiating a research program, and this is exactly what is currently taking place at UK. The Director of the new USDA Forage\Livestock, Dr. Jim Strickland, has taken an interest in this question, along with the other pressing priorities his group will address. A cooperative USDA\UK research effort has begun to explore possible causes of the feed-refusal problem, including the possible connection between the black patch fungus and feed refusal.

Producers who have red clover hay that has been clearly and consistently refused by livestock may wish to contact their county Extension Agent for Agriculture. Samples of such hay could be useful in our preliminary investigations.



By William Nesmith

Tomatoes Tomato fruit rots have historically caused major losses for tomato growers (both commercial and gardener) during protracted wet weather, especially for unprotected fruits in contact with the soil, or very near the soil, and during post-harvest handling. In recent times, however, fruit rots have been of minor importance for commercial tomato growers that are using raised beds covered with film mulch, stake the plants, and follow a regular spray program to combat foliar and fruit diseases. This year, growers in regions of Kentucky that have received excess and frequent rains are reporting increased problems with fruit rots, especially in areas of the field that experienced standing surface water for several hours and their spray intervals were opened up rather than closed up. Buckeye- like rots (caused by Phytophthora species) are the main problems, but Pythium species are also involved at a significant level, too.

The losses are particularly serious to the lower clusters of fruit, which are the first to ripen and normally bring the highest price. During prolonged, warm wet weather like we experienced last week, buckeye rot can affect a high percentage of unprotected fruit that become contaminated with the pathogen from muddy water and soil splashing on the fruit. Most of the fungicide sprays that commercial growers were using would have controlled buckeye rot, had the material been in place on the fruit surface when the spores arrive. Buckeye rot is not a major problem if fungicides are applied properly for general control of foliar and fruit diseases on a close schedule (5 to7-day schedule) during warm, wet weather. Many growers with serious problems allowed their spray intervals to become more opened, rather than closing it; several with problems are reporting spray intervals of 10-21 days.!

It is important to apply fungicides early, and to uniformly cover all fruit with the fungicides, being sure that the lower fruits and those in the center of each plant and the undersides are also receiving the protective layer of fungicide. Check and follow the manufacturer's directions, but close the spray interval to the shortest interval allowed in wet weather with fruit on the plants. Fungicides are most needed for these diseases when the soil is wet, so get them on if you find a period when the spray will dry a few hours before the next rain event. Operating from a sodded spray/drive strip, or walking- them-on using back-pack mist blowers, becomes important in the control of fruit diseases during protracted, periods of warm, wet weather. Many growers told me that their soils were too wet to support tractors for 10 days or longer during one or more periods this season.

Growers and coops with these fruit rots will need to take additional care during harvesting, handling, and packaging to prevent spread, pathogen infiltration during washing, and infection. Be very careful to keep all fungicide applications legal, too. See ID-36, for more details on the chemical options available. As a preventive treatment, the use of mefenoxam (Ridomil Gold or Ultra Flourish) in soil directed pre and post applications could have greatly reduced losses from these diseases, but such options are NOT available at these later stages of production. Some consultants are advising growers to spike foliar spray mixes with these materials labeled for soil applications. But this approach can result in illegal and detectable residues - destroying Kentucky's fresh market tomato industry. I strongly urge Kentucky's vegetable industry to apply only labeled products and in a manner approved on the label.

By Ric Bessin

Squash bug Squash bug adults are active in winter and summer squashes. These inch-long sucking bugs damage cucurbit plants by removal a large amounts of plant sap. With transplants and small plants that have small, restricted root systems, squash bugs can remove sap to the extent that the plants wilt and may even die. Later in the summer on larger plants, squash bugs remove the sap from leaves and stems and can cause leaf yellowing and necrosis. More importantly, squash bugs transmit the bacteria causing Yellow Vine Decline in cucurbits.

Squash bugs are commonly found on the undersides of leaves where they lay their eggs. With plasticulture fields, squash bugs are often at the base of the plants beneath the plastic. The protection they get under the plastic may make control with foliar sprays more difficult.

During the coming weeks, squash bug will lay eggs on the undersides of leaves. Upon hatching, squash bug nymphs resemble aphids. As they get older, they take on a grayish appearance as they develop a waxy coat. Generally, they younger nymphs are much easier to control than the larger nymphs. In addition, treatments targeting the young nymphs will facilitate superior coverage as the plant canopy is smaller.

Because squash bugs persistently transmit the bacteria causing Yellow Vine decline, control of the disease is through early and effective control of the adult squash bug. Many growers are using at-planting systemic insecticides for control of cucumber beetles, these treatments will also control squash bug for three to four weeks after transplanting. As these treatments begin to lose their effectiveness, growers need to monitor for squash bugs and extend the control with foliar insecticides.



By John Hartman

White pine During recent weeks, white pines in central Kentucky and in Lake Cumberland area counties, have been showing symptoms of browning and premature loss of last year's needles. The problem is most noticed in plantings having many trees such as landscape screens and windbreaks or Christmas tree plantations and nurseries, probably because not all trees are involved and the problem is easier to find where there are groups of trees. This problem has left the affected trees quite bare, with the only green foliage remaining being the needles just emerged from the newest candles. On affected trees, clumps of dead needles are easily combed out of the branches and are now brown; earlier in spring, before the needles became desiccated, these needles would have been a faded green color with bands of yellow. The trees themselves are still very much alive and the newly emerging needles are healthy, but with foliage less dense than normal.

Based on specimens sent to the plant disease diagnostic laboratory and on digital consulting cases submitted last week, the problem is appearing over a widespread area in central and southern Kentucky. Within the individual plantings, perhaps 10-25% of the trees are affected and the severity of the affected trees varies from almost complete loss to loss of perhaps half of last year's needles. Many of the trees growing in the same planting are not affected. Normally on white pine, last year's needles turn yellow and drop in the fall.

The likely cause of the premature defoliation is an air pollution event sometime last summer. The symptoms we are seeing are typical of oxidant air pollutants such as ozone and peroxy acetyl nitrate (PAN), or possibly sulfur dioxide. Injury to pines often occurs during warm weather when pollutants accumulate in stagnant air. First symptoms consist of yellow banding on the needles which may be inconspicuous during the growing season. The problem often intensifies during the winter and spring in the form of browning and defoliation. Since these pollutants are not usually confined to a small area, one would expect symptoms to appear over a wide area of the state. Although the exposure was general, not all trees within a planting are affected. This variation within a planting reflects genetic differences between trees grown from seedlings and it is normal to see these different responses to air pollution damage within a population of white pines.

When did the air pollution event(s) occur? The following information is based on consultations with Tom Priddy, our U.K. Agricultural Meteorologist and information obtained from the EPA AIRNow air quality web site. Last year, being cooler and wetter than usual, there were few hot, hazy days with elevated ozone levels. However, elevated levels sufficient to cause plant symptoms may have occurred on May 24, June 24-26, or August 26. For sensitive plants, daily averages of 0.05 ppm or hourly exposures of up to 0.1 ppm are sufficient to cause symptoms. Thus, our best guess of when the damage we are seeing now originated is last summer.

What is the prognosis for affected white pines? The affected trees are not dead or even dying. They will undoubtably be growing under some stress, at least until the new needles are fully functioning, and even then they will have fewer energy reserves than unaffected trees. Growers will need to be sure that the affected trees receive adequate water through the season and that infectious diseases, insect pests, and weeds are managed. For now, affected trees may not be as pleasing as they would have been, but perhaps will be back to normal in another year.



By Lee Townsend

Springtail Springtails, bark lice, and millipedes are frequent visitors to the Insect ID lab via sample mailing tubes. Some of these creatures thrive during periods when frequent rain and high humidity provide favorable conditions and promote mold growth that is an important food source.

Springtails are tiny wingless insects that can flip into the air, giving them the appearance of tiny fleas. They would go completely unnoticed except that hundreds can accumulate on surfaces like a small, dusty gray carpet that moves.

Many springtails live in rich soil or leaf litter associated with fungi. Springtails become abundant among wet leaves, soil, and plant material along a house foundations or sidewalks where they can be a temporary annoyance. They also can occur around floor drains, in damp basements, and crawl spaces. Masses of these insects can be swept up and discarded.

Most common springtails do not survive in dry conditions. Any steps to improve ventilation and promote drying are the best long term solutions. Removal of accumulations of wet leaves or other organic matter will eliminate breeding sites. Aerosol household insecticides can be used to treat infestations but will provide only temporary relief if the favorable conditions are not corrected.

Bark lice are light colored soft-bodied insects that can be found clustered on tree trunks. They don't feed on leaves or bark so they pose no problem but we usually don't see them in great numbers.

millipede Finally, millipedes are nuisance invaders in some homes now. Those what make it inside should be swept up and discarded. They will not become established in the home so there is no need for an insecticide application. The source of these creatures may be heavily mulched areas around the foundation or accumulations of leaves. Removing these and promoting penetration of sunlight and air circulation and help make the habitat unfavorable to them. Also check door sweeps for a tight fit - this may be the way they are gaining access to the home.

News and Views



By John Hartman

Quintec (quinoxyfen) fungicide is a new protectant fungicide labeled for control of powdery mildew in grapes. Quintec is normally applied on a 14-21 day schedule starting early in the season before powdery mildew infections begin. The fungicide is not to be used within 14 days of harvest and no more than 5 times per season. In Kentucky, Quintec would likely be used in combination with a black rot fungicide; it is compatible with other commonly used fungicides and insecticides. Based on information from the national Fungicide Resistance Action Committee, this fungicide has a chemistry and mode of action different from other fungicides such as strobilurins and sterol biosynthesis inhibitors. Thus, it can be alternated with these fungicides to help prevent fungicide resistance development by the powdery mildew fungus. Quintec is manufactured by Dow AgroSciences.



By Julie Beale and Paul Bachi

Recent diagnostic samples have included Pythium root rot on alfalfa and on soybean; head scab on wheat; angular leaf spot, blue mold, target spot, black shank, Pythium root rot, tomato spotted wilt virus, manganese toxicity and temporary phosphorus deficiency on tobacco.

On fruit and vegetable samples, we have seen anthracnose and black rot on grape; anthracnose on blueberry; brown rot on cherry; early blight, bacterial speck, Septoria leaf spot, Rhizoctonia stem rot, and tomato spotted wilt virus on tomato; bacterial spot on pepper; and stinkbug injury on sweet corn.

On ornamentals and turf, we have seen anthracnose on begonia; stalk borer on lily; black root rot on petunia; Phytophthora aerial blight, black root rot and Rhizoctonia root rot on vinca; yellow poplar weevil injury on tuliptree and magnolia; black spot on rose; leaf blister on oak; anthracnose, brown patch and Drechslera leaf spot on ryegrass; and melting out on bluegrass

Scout Cat


By Patty Lucas, University of Kentucky Research Center

UKREC-Princeton, KY, June 11-18, 2004
Black Cutworm 0
True Armyworm 1
Corn Earworm 3
European Corn Borer 0
European Corn Borer 1

To view previous trap counts for Fulton County, Kentucky go to - and click on "Insect Trap Counts".

For information on trap counts in southern Illinois visit the Hines Report at - 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