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No. 08/May 17, 2002

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Crop Session to Focus on Drift
Producers, agribusiness dealers, and crop scouts are invited to participate in a "Crop Systems Management" workshop on June 11 at the Northern Illinois Agronomy Research Center, and is sponsored by University of Illinois Extension.

Listening Sessions for Organic Growers
University of Illinois Extension and the College of ACES Organic Taskforce will sponsor three listening sessions in June and July for organic growers in Illinois. The purpose of the listening sessions is to obtain input from current organic growers about pressing issues in Illinois organic crop production. We (University of Illinois staff and faculty) will be doing the listening.

Do you want to discuss issues about the production and marketing of organic commodities, pest management, or other issues related to organic crop production? This is your opportunity to discuss current issues in organic crop production in a round-table setting. Your input will guide future research and education programs of the Organic Taskforce.

What Is This?
What if there were 50 Extension professionals at your local Extension office who could help diagnose your plant or pest problems, who had a range of expertise that included field crops, forages, turf, fruit, commercial vegetables, and home pest problems? University of Illinois Extension's Distance Diagnostics system makes that possible by bringing every Extension office in the state almost instant access to the diagnostic skills of these experts.

Bean Leaf Beetles and Bean Pod Mottle Virus (a 2002 Management Perspective from Illinois)
We have received numerous questions regarding early-season control of bean leaf beetles, which potentially can transmit bean pod mottle virus to soybeans. Based on research conducted in Illinois, entomologists and plant pathologists believe that insecticides to control bean leaf beetles are warranted only to reduce feeding damage (if a threshold number of beetles has been reached). In general, application of insecticides to control of bean leaf beetles to manage BPMV is not warranted in Illinois.

The bottom line is that we need to learn a whole lot more about this association before suggesting management tactics focused on the insect. Although we encourage everyone to watch for bean leaf beetles in early-planted soybeans, we strongly suggest that you focus on leaf-feeding injury rather than attempt to "stop the virus."

Some Reports of Black Cutworm Larvae Feeding on Corn, and Moth Captures Continue
Not surprisingly, with storm fronts moving through Illinois with frequency, captures of adult black cutworms continue. We can project dates for the first signs of cutting by black cutworm larvae, but at this late date, suffice it to say that corn that has emerged should be scouted right now, regardless of location within the state. Corn planted from now on also will have to be scouted vigilantly after it emerges.

Southern Corn Leaf Beetle Injury Revisited
Although we have not received additional reports of southern corn leaf beetles causing injury to corn seedlings, it's still advisable for folks in the southwestern and western counties to watch for this pest. We recently received a couple of very good photographs of the adult (with some size perspective) and classic symptoms of feeding injury. The photos clearly show what you should be looking for.

Sandhill Cutworms in Northwestern Illinois
We have received a couple of reliable reports of sandhill cutworms injuring seedling corn in sandy soils in southern Carroll County. Sandhill cutworms can be devastating in sandy soils because they feed exclusively below ground, usually killing any plant on which they feed. This finding of sandhill cutworms should prompt farmers who have planted corn in sandy soils to be on the lookout for this pest.

Corn Rootworm Larvae Should Begin Hatching Soon
Corn rootworm larvae usually begin hatching from overwintering eggs at about this time of year throughout central Illinois. We can use accumulations of degree-days to predict larval hatch, or we can look for the appearance of fireflies, which often coincides with rootworm larval hatch. But based on accumulated degree-days at the 4-inch level in soil, the occurrence of fireflies and rootworm larval hatch may not occur at the same time this year. However, it's always wise to keep an open mind--rootworms have fooled us before.

Heads Up for Stalk Borers
It's probably a bit early for farmers in northern Illinois (where quite a bit of corn has been planted) to be concerned about stalk borers, but degree-day accumulations can provide a "heads up." The data suggest that farmers in southern counties (where very little corn has been planted) should watch for stalk borers; however, farmers in central and northern Illinois probably won't see stalk borers right away. When (if) temperatures become more late spring-like, development of stalk borers will accelerate.

A Few Insect "Thumbnail" Reports
This article contains some brief reports of occurrences of a few insects in Illinois or elsewhere in the Midwest, including flea beetles, southwestern corn borers, European corn borers, and alfalfa weevils.

Musings About Weed Control in Corn and Wet Field Conditions
It's somewhat difficult to consider all possible weed control questions or scenarios for a crop so varied (some still in the bag, some receiving postemergence herbicides), but this article presents some items for consideration with respect to weed management in corn. Possible scenarios addressed include the following:

No herbicide applied, corn not planted
No herbicide applied, corn has been planted
Herbicide applied, corn not planted
Herbicide applied, corn has been planted

Factors Contributing to the Likelihood of Corn Injury
Several factors contribute to the likelihood that a corn crop will exhibit injury symptoms following a herbicide application. If the cause is clear, the explanation can also be clear, but if several factors contribute to corn injury, fingers tend to be pointed in several directions and often little is resolved.

Factors discussed in the article include crop genetics, the environment, and the herbicide itself.

More on Delayed Planting
Heavy rains over the weekend have a lot of us wondering when we will ever get back into fields (or into them for the first time). It's a familiar refrain for this most frustrating planting season, especially in southern and southeastern parts of the state.

Pressing questions continue to center on yield losses to be expected, as planting delays stretch out, and whether alternatives to corn should be considered.

Predicting/Measuring Nitrogen Loss
This article describes different techniques to estimate or measure the amount of N loss that might have occurred during this excessively wet period. The following techniques are described:

Amino Sugar-N Test (Illinois N Soil Test)
Presidedress Nitrate Test (PSNT)
Supplemental Nitrogen Strip
Estimation of N Loss Based on Soil Temperature

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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