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Regional Reports

August 10, 2001
Extension center educators, unit educators, and unit assistants in northern, west-central, east-central, and southern Illinois prepare regional reports to provide more localized insight into pest situations and crop conditions in Illinois. The reports will keep you up to date on situations in field and forage crops as they develop throughout the season. The regions have been defined broadly to include the agricultural statistics districts as designated by the Illinois Agricultural Statistics Service, with slight modifications:

· North (Northwest and Northeast districts, plus Stark and Marshall counties)

· West central (West and West Southwest districts, and Peoria, Woodford, Tazewell, Mason, Menard, and Logan counties from the Central district)

· East central (East and East Southeast districts [except Marion, Clay, Richland, and Lawrence counties], McLean, DeWitt, and Macon counties from the Central district)

· South (Southwest and Southeast districts, and Marion, Clay, Richland, and Lawrence counties from the East Southeast district)

We hope these reports will provide additional benefits for staying current as the season progresses.

Northern Illinois

Rainfall throughout the area last week was variable, as some areas received more than 2 inches and others received 2 tenths or less.

Reports have been received of several soybean fields being treated for soybean aphids. Some of the treated fields had not expressed any visible symptoms prior to being treated. A LaSalle County soybean field has been monitored for soybean aphid populations weekly for the past 6 weeks. Aphid populations last week averaged about 200 per plant, compared to more than 1,000 per plant the previous week. Refer to last week's issue of the Bulletin regarding treatment decisions for soybean aphids.

Spider mite damage has appeared throughout the region, primarily along field borders. However, spider mite populations appear to have naturally "crashed" in several fields that had showed damage.

Dave Callan, LaSalle County FS, reports several instances of soybean SDS in southwest LaSalle County. To date, SDS is limited to this area and parts of Putnam County.

Southern Illinois

Southern Illinois has been hazy, hot, and humid for the last week. High daytime and nighttime temperatures continue to stress the crop and may potentially affect yield. Corn is R4­R5, and producers have called expressing concern about poor pollination and/or kernel abortion. Gray leaf spot and smut are being found in some fields, and early symptoms of anthracnose stalk rot are beginning to appear.

Soybeans are R4, and scattered reports of SDS are coming in from I-70 all the way to the southern tip of the state. There have been reports of poor weed control, primarily waterhemp, prickly sida, giant ragweed, and nightshade, in some soybean fields where post applications were delayed.

The primary insect problem continues to be potato leafhopper in alfalfa.

West-Central Illinois

High temperatures and dry weather continued during the week. The prolonged hot weather is threatening the once-anticipated high yields for corn and soybean.

The extended high temperatures are thought to be causing some yield reduction in corn. Additional "firing" of plants in some fields has been observed, and ear fill and kernel depth may be curtailed. No major pest problems have been reported; however, some leaf diseases, such as gray leaf spot, can be found in some fields.

Late-season weeds have emerged through the canopy of some soybean fields; they include primarily waterhemp, giant ragweed, and velvetleaf. SDS and spider mites can be found in some fields also.

Farmers and their families are making plans to attend the Illinois State Fair in Springfield, August 10­19, and Agronomy Day at the University of Illinois, August 23.

The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

Subscription information: Phone (217) 244-5166 or email
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