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No. 10/June 01, 2001

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Reports of Armyworm Injury in Corn and Wheat Continue
Observations of armyworm injury have begun to slow down south of Interstate 70 in Illinois. However, reports of armyworm infestations in central and northern counties are becoming more common. We've also heard that armyworms can be found easily in wheat fields throughout much of central and east-central Illinois.

Producers are encouraged to continue scouting efforts in wheat and be ready to apply rescue treatments as needed. Hopefully, diseases and parasitoids will reduce populations of armyworms to below economic levels in the following generations.

Corn Rootworm Hatch Very Early This Year
As we predicted, the corn rootworm hatch is early this year, and we anticipate numerous calls in the next several weeks confirming larval feeding and injury. Because of the early hatch and small developing root systems, fields that support heavy infestations of corn rootworm larvae could begin to show signs of stress (leaning and wilting plants), especially in areas that have been dry. Soil insecticide performance is often compromised in dry-soil conditions.

Remember to Scout for First-Generation European Corn Borer
Injury caused by first-generation European corn borers will occur soon. This article addresses the following questions concerning European corn borer management.

What are corn borer "action sites"?
Is treating an action site with an insecticide a good idea to prevent corn borers from causing problems in my cornfields?
What's the best approach to scout a field for first-generation corn borers?
Many plants within my field have whorl-feeding injury, but I can't find any borers. Should I treat anyway?
When will corn borers begin to tunnel into stalk tissue?
If I find European corn borer larvae within the whorls of Bt-plants, does this mean that the Bt-corn is not working?

Economic Impact of Bt-Corn Hybrids: Summary Available
A report titled "Agricultural Biotechnology: Updated Benefit Estimates" was published in January of 2001 by the National Center for Food and Agricultural Policy. In this study the aggregate costs and benefits to U.S. producers who planted Bt corn (1997-1999) were calculated.

This report clearly elucidates that when European corn borer infestations and market prices are low, the use of Bt hybrids may not result in profits. The purchase of Bt hybrids is like taking out an insurance plan against European corn borers. The insurance premium will not return a dividend every year.

Soybean Aphid Regional Pest Alert Available Online
In anticipation of the soybean aphids appearing in soybean fields, we suggest you visit our IPM website and view the regional pest alert that provides information on the distribution and life cycle of the soybean aphid.

Don't Forget to Scout for Stalk Borers
With all the attention directed at armyworms during the past 10 days, don't forget about the other lepidopteran pests, including stalk borer. Scouting is recommended when accumulated heat units are between 1,300 and 1,400, and 50% movement occurs between 1,400 to 1,700 accumulated heat units.

Southwestern Corn Borer Moth Captures Common in Southern Illinois
By keeping track of when southwestern corn borer moths have been captured in your area, you can begin to estimate important life-cycle events for this insect. This article provides some details about the life cycle of the insect.

Weather Woes and Crops
The past 10 days or so, beginning about May 20, have brought us very poor weather for the young corn and soybean crops that are trying to get started growing in Illinois. While crops, especially in southern and eastern Illinois, have benefited greatly from the rainfall, continued cool and cloudy weather has slowed the growth of the crops and has given the crop a pale, unhealthy appearance. The corn, especially that with only three or four leaves, looks especially poor. Larger corn and just-emerging soybean plants have not been as affected, but they also don't look as healthy as we'd like.

On the positive side, most plant stands are good and most root systems appear to be in good shape. These factors will be important in maintaining good yield potential in fields once the weather returns to more average conditions.

Regional Reports
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.

This week's issue includes reports from east-central, northern, southern, and west-central Illinois.

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

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