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No. 08/May 18, 2001

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Mark Your Calendars Now for the 2001 University of Illinois Agronomy Day--August 23
On August 23, 2001, the 45th Annual Agronomy Day will be held at the Crop Sciences Research and Education Center (South Farm) beginning at 7 a.m. The theme for this year's program is Agriculture Is for Everyone. This program serves as an annual showcase for faculty to discuss their latest research findings with clientele throughout Illinois and also from neighboring states. The article lists the topics to be featured at this year's program.

Armyworms Marching Throughout Southern and Central Illinois
Reports of serious damage to corn, wheat, and grass hay fields poured into our offices during the latter part of the week of May 7 and the first half of the week of May 14. Reports of grass hay fields and some wheat fields being completely stripped (all leaves devoured, only stems remaining) have been numerous. This article discusses how much longer will these armyworms will continue to cause this much damage.

Black Cutworm Cutting Observed in Cornfields and Soybean Fields
We've received a few widely scattered reports of black cutworm cutting in corn and soybean fields. In addition, intense flights of black cutworm moths continue to occur in isolated areas of the state.

Don't let your guard down just yet concerning black cutworms. Take the time to scout your cornfields and soybean fields and be ready to respond as needed.

Grape Colaspis Larvae Are at Work
Reports of grape colaspis injury are becoming more common. As indicated in last week's Bulletin, rescue treatments are not an effective option for this insect pest. Severely infested fields with significant stand reductions may require replanting.

Early Corn Rootworm Larval Hatch Anticipated: An Update on Heat-Unit Accumulations
The soil heat-unit accumulations (January 1 to mid-May) for 2001 are very similar to last year's for this period. By early next week (May 21), the corn rootworm larval hatch will be under way in much of central Illinois. This represents an early hatch.

If the dry and warm conditions persist across much of east-central and central Illinois counties, good-to-excellent survival of larvae is anticipated following the hatch. In addition, soil insecticide performance will not be enhanced by these dry soil conditions.

Heat-Unit Accumulations Indicate Stalk Borers on the Move
Stalk borers may threaten corn in some areas of Illinois quite soon, so be watching for them. This article examines the life cycle of the stalk borer, descriptions of plant injury, scouting tips, and suggestions for control.

Bean Leaf Beetle Adults Can Be Found in Early-Planted Soybeans
Densities of bean leaf beetles should be much lower than last year. We anticipate low overwintering survival of bean leaf beetle adults in the northern one-third of Illinois.

This article includes a table that allows producers to effectively evaluate the wisdom of applying a rescue treatment based on bean leaf beetle adult densities, projected market value of soybeans, and the cost of a rescue treatment.

Soybean Aphids--A Caution About Jumping to Conclusions
Last week's issue of the Bulletin included a brief article about finding the first soybean aphids of the season in Illinois. However, our resident aphid expert has not verified the species. Therefore, the report about "the first soybean aphids of the season" was premature.

This information once again underlines the importance of accurate identification of a pest (or nonpest) insect. At this point, we still are not sure that soybean aphids have "carried over" from last year.

Working with the Weather to Avoid Drift
This spring has been windy. In the challenge to get crop protection products applied in a timely and responsible way, a key component is drift control. Wind must be worked with as is, and the applicator's choices are when to spray or not spray. This article discusses the option of nighttime spraying.

Maximum Corn Sizes for Postemergence Herbicides
With more than 90% of the Illinois corn crop in the ground and more than 80% of it emerged and rapidly growing, we need to start considering what types of options we have for weed control on those acres where the soil-applied herbicides didn't get applied or are not working to their full potential due to lack of rainfall. We need to start thinking about how we are going to control later-emerging grass and broadleaf weed species.

It is always important to keep maximum corn sizes in mind when planning postemergence herbicide applications. This article discusses some of these maximum sizes for 2,4-D-containing products, atrazine-containing products, and dicamba-containing products.

Dry Weather and Crops
This article discusses the effects of dry weather on wheat, corn, and soybean.

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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