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No. 03/April 13, 2001

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IN THIS ISSUE:
Corn Flea Beetle: Expectations for Injury in 2001
We've received many calls regarding corn flea beetles as producers finalize their preparations for planting. The questions covered in this article are designed to answer many of the inquiries concerning the biology and management of these potentially damaging beetles.

Why do we refer to these insects as corn flea beetles?
Where do corn flea beetles overwinter?
Why are corn flea beetles of more concern to the seed-production industry?
Are there any other hosts that corn flea beetles will feed on?
What is the outlook for economic infestations of corn flea beetles this spring?
How does anticipated corn flea beetle survival this winter compare with last year?
Can you scout for corn flea beetles and use economic thresholds to rescue infested fields?
Do seed treatments represent a good management approach for corn flea beetle management?

White Grubs: Expectations and Management Recommendations for 2001
During the past several years, producers throughout Illinois have reported increasing problems with grubs (white grubs, wireworms, grape colaspis) in corn. this article provides some questions and answers and should shed some light on the biology and management of white grubs.

What types of white grubs are most frequently found in Illinois cornfields?
How easily can larvae of white grub species be identified?
Why is it important to separate species of white grubs?
Why are true white grub larvae of more importance than annual or Japanese beetle larvae?
Are some cornfields at greater risk to true white grub infestations?
Are there any good scouting approaches and thresholds for true white grubs?

Black Cutworm Moths Reported Throughout the State
First captures of black cutworm moths have been reported throughout the state of Illinois. As soon as corn gets planted and begins to emerge in southern Illinois, cutting injury caused by black cutworm larvae could be evident. Be on the alert for pinholes in the leaves as soon as the seedlings emerge.

Other Creatures You May Encounter in the Soil
People digging in corn stubble now and in cornfields after they emerge search for a lot of things, including the possible presence of cutworms, grape colaspis larvae, white grubs, and wireworms. However, there are a lot of other creatures, mostly harmless and often beneficial, that you might encounter as you dig in the soil, including crane fly larvae and millipedes.

Any New Products Labeled for Control of Corn Rootworm Larvae?
Within the past week, we learned about some rumors regarding other "new" products that are labeled for control of corn rootworm larvae. In at least one area of Illinois, the rumors suggest that "rootworm larvae" has been added to the labels of Pounce 1.5G (from FMC) and Warrior T (from Syngenta). Although it is true that both of these products are labeled for control of some soil insect pests in corn (for example, cutworms and wireworms), a review of the labels reveals that "corn rootworm larvae" is not listed. Warrior T is labeled for control of corn rootworm adults but not for control of the larvae.

Alfalfa Weevil Activity Evident in Central Illinois
The recent very warm weather has stirred things up in the world of alfalfa weevils. This article discusses the life cycle of the alfalfa weevil.

A comparison of degree-day accumulations this year with degree-day accumulations at a similar time last year reveals that alfalfa weevil development this year is significantly behind the pace set last year.

People throughout southern and central Illinois should be scouting for alfalfa weevils now, looking for the small larvae in folded terminal leaves and for pinholes in the leaves, the first symptom of larval injury.

Stewart's Bacterial Wilt--Potential Problem?
Stewart's bacterial wilt, caused by Erwinia stewartii, is spread by adult flea beetles that feed on corn. While this bacterial disease is more serious on sweet corn, symptoms of the disease can be seen on field corn, especially during years when high flea beetle populations survive the winter. The potential for Stewart's wilt disease development depends on the population of adult flea beetle vectors that survive the winter.

Effectiveness of Soil-Applied Herbicides
Soil-applied herbicides still remain an important part of weed-control programs in corn- and soybean-production systems. Regardless of when or how a herbicide is applied to the soil, the effectiveness of soil-applied herbicides is influenced by several factors, including its absorption into the germinating weed seedling, the target depth for herbicide placement, rainfall, and dry soil conditions.

Herbicide Resistance: Where Are We?
Over the last decade there has been a dramatic increase in the appearance of herbicide-resistant weed biotypes, in Illinois and worldwide. This article addresses the following questions about herbicide resistance.

What factors have contributed to the increase in herbicide-resistant weed biotypes?
What about resistance to glyphosate?
What can be done to prevent herbicide resistance?

Kochia Biology and Management
Kochia (Kochia scoparia) is an early-emerging summer annual species commonly found in the western United States. In recent years, kochia has become more common in many areas of Illinois. Kochia possesses several characteristics that make it well suited as a weed in agronomic production systems.

This article discusses kochia morphology and biology, herbicide resistance, and control.

Control of Volunteer Corn
Poor cornstalk quality last fall resulted in significant seed loss at harvest in many areas of Illinois. While some of this corn seed was lost due to fall germination, and some was likely lost during the winter months, volunteer corn may be a common weed problem in soybean fields and cornfields during 2001. This may not be much cause for alarm to everyone, but some volunteer corn plants may contain traits not approved for human consumption or export. This article reviews options for volunteer corn control in soybeans and corn.

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.

Beware of Phone-y Pesticides
Pesticide telemarketers are at it again, and some of them will tell you anything to make the sale. This article discusses the pitfalls of buying pesticides over the phone.



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

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