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No. 05/April 27, 2001

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Be Alert for Cutting of Corn Plants by Black Cutworms in Southern Illinois
In troubleshooting fields for suspected cutworm problems, it is helpful to assess the stage of black cutworm development. This will enable you to determine the number of days that cutworms are likely to continue feeding within a field and estimate the potential number of plants that may be cut.

Included are a true-to-scale guide that can be used to improve your cutworm-management decisions and a table listing insecticides that are labeled for use as rescue treatments for black cutworms.

Correct Identification of Cutworm Species Is Important Each Spring
This article describes species of cutworm that may be confused with balck cutworm, including the claybacked cutworm, the sandhill cutworm, the dingy cutworm, and the variegated cutworm.

It is important to identify your cutworm species properly. Mistaking dingy cutworms for black cutworms could cost a corn producer a needless expense if a field is treated. On the other hand, not reacting to an infestation of black, claybacked, glassy, or sandhill cutworms could be a costly mistake.

Moths in Pheromone Traps or Blacklight Traps
People who operate either pheromone traps or blacklight traps expect to capture moths at this time of year, but only a few of them create any economic concerns. Obviously we all want to know about the activity of black cutworms when they begin to fly into Illinois from southern states at this time of year. However, wheat growers might be interested particularly in armyworm activity. Armyworm moths have been captured in southern Illinois, so wheat producers can anticipate finding armyworm larvae in their fields soon.

Wireworms Have Been Found in Some Fields
We have received our first confirmed report of wireworms attacking planted corn seeds and young seedlings. Wireworms cannot be controlled with "rescue" treatments. If wireworms are discovered damaging corn seeds and seedlings and reducing the plant population, the only consideration is whether the field or parts of the field need to be replanted.

Alfalfa Weevils Are Still Busy
Population densities of alfalfa weevils have exploded in many fields, with economic damage obvious. However, so many producers are busy planting corn and so many applicators are spraying herbicides that the alfalfa might be ignored.

A table is included that shows the products suggested for control of alfalfa weevil larvae, recommended rates of application, and numbers of days between application of a given product and harvest of hay.

Flea Beetles and Southern Corn Leaf Beetles in Southern Illinois
Some corn leaf beetles and southern corn leaf beetles have been found in a cornfield in St. Clair County, causing minor feeding injury. Both of these insects have figured prominently in our early-season hand-wringing during the past few years, so people will want to know about their presence.

Far all of you who are scouting in the few fields that have emerged, keep watching. Southern corn leaf beetles are small and hard to find at first. But watch carefully and you will discover them eventually.

Maybe the Plant Clinic Can Help!
The University of Illinois Plant Clinic services include plant and insect identification; diagnosis of disease, insect, weed, and chemical injury symptoms (chemical residue testing not available); nematode assays; and help with nutrient-related problems, as well as management recommendations involving these diagnoses. The clinic operates from May 1 through September 15.

Comprehensive Website for Soybean Varietal Information
The Varietal Information Program for Soybeans (VIPS) is a great tool for the analysis of the performance of soybean varieties. VIPS enables the user to compare selected attributes of individual varieties with ease. VIPS has recently been redesigned to be more user-friendly and comprehensive.

An additional component of VIPS is designed for users interested in in-depth analysis of soybean composition.

Sampling for SCN--There Is Still a Little Time
Predictive soil sampling and analysis for the soybean cyst nematode (SCN) can provide timely information for growers, especially those considering planting soybeans this growing season. Growers can use the analysis to select SCN-management strategies and tactics that will minimize losses.

IPM Approach for Managing Soybean Cyst Nematode
An ideal program to manage soybean cyst nematode (SCN) infestations should integrate the following: detection through scouting and sampling procedures and crop rotations utilizing nonhost crops and SCN-resistant soybean varieties. Maintaining proper soil fertility and pH, managing other soybean diseases and pests, and proper planting methods also help to keep plants vigorous and better able to buffer the effects of SCN. The most effective management systems have and will continue to involve integrated approaches. No single method will manage SCN as effectively.

Aphanomyces Root Rot Can Be a Serious Disease for Alfalfa
Poor growth of seedling alfalfa in wet or slowly drained fields may be due to several diseases. Aphanomyces root rot causes death and stunting of seedlings as well as more subtle disease of established plants that can result in significant yield reduction. This article describes the disease and discusses options for management.

Waterhemp--Biology, Identification, and Management Considerations
Waterhemp will likely continue to be a problematic weed species during the 2001 growing season. This weed represents a prime example of why an understanding of weed biology/ecology is needed to implement effective management strategies.

This article discusses waterhemp biology, identification, management considerations, considerations with soil-applied herbicide programs, and considerations with postemergence herbicides.

Too Early or Too Late?--Cold Injury and Planting Date
The below-freezing temperatures on April 18 had minor effects on Illinois crops but only because the crops--especially soybean--were not emerged on very many acres. The suggestions in last week's Bulletin that soybean might escape serious injury turned out to be too optimistic.

Estimating Alfalfa Quality in the Field
When to take the first cutting is an important decision for those desiring to harvest high-quality alfalfa. Estimating the relative feed value (RFV) of standing alfalfa can be accomplished by using PEAQ (predictive equations for alfalfa quality), a system developed at the University of Wisconsin and used in Illinois.

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 northern, southern, and west-central Illinois.

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

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