Issue No. 17, Article 4/July 30, 2010
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.
Heavy rainfall in the northern portion of the region from late Friday, July 22, to Sunday, July 25, is the story of the week. Freeport in Stephenson County recorded over 12 inches during that period, and over 10 inches was reported in portions of Winnebago County. DeKalb County recorded amounts from at least 2.5 inches in the northern portion of the county up to 12 inches. The southern part of the region received rainfall, but not in such high amounts. Reports from Stephenson and Winnebago Counties note standing water in many fields, with some crops under water. Some rural bridges were washed out, and roads, fences, and farm buildings were damaged.
Concerning field activity, fungicide application on corn has wrapped up, with some soybean fields now receiving applications. Soybeans have been growing well, and plant heights in numerous fields are higher than any time last year. There have been no reports of economic crop insect damage except some treatment for potato leafhopper damage in alfalfa prior to the week's rainfall.
Rainfall events are becoming more scattered. Depending on location, one may be hoping for rain or wishing it would stop. The earliest-planted corn is approaching dent stage. Gray leaf spot is the most prevalent disease found, with common rust in distant second place. Northern corn leaf blight may also be observed in some fields, and fields that were injured earlier by hail may be showing some Goss's wilt. As grain fill progresses, nitrogen deficiency symptoms are becoming more evident.
Soybean development ranges from vegetative up to around R4. Overall there is little evidence of foliar diseases other than Septoria brown spot and downy mildew. The insects being found most commonly are Japanese beetles, southern corn rootworm beetles, grasshoppers, and stink bugs. Japanese beetle numbers appear to have been declining rapidly in the past couple of weeks, possibly due to earlier emergence and higher temperatures this summer.
The weather across the region was quite variable over the past week. The western side of the region got anywhere from 3 to 7 inches of rain, and many fields are flooded or have standing water. The eastern side received only 1/2 inch to 1-1/2 inches.
Corn is still a little variable. The earliest-planted corn is at dent stage, with the rest not far behind. Many fields have some bare ear tips. There will be some really good yields this year, but it will be hard to predict field averages with all of the wet and compacted spots. Some reports of Diplodia ear rot and northern corn leaf blight are becoming more common. Many fields are showing firing on the lower leaves.
Soybeans are mostly in the R3 stage, with some early-planted fields at R4. There are very few reports of diseases and insects.