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No. 06/May 03, 2002

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Estimating Alfalfa Quality in the Field
When to take the first cutting of alfalfa is an important question for those desiring to harvest high-quality hay or haylage. 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 the past few years.

White Grubs and Wireworms Can Injure Slow-Growing Corn
Wet weather has delayed planting in many areas, and cool soils are not encouraging rapid corn growth. Consequently, subterranean insects such as white grubs and wireworms can ravage slow-growing corn seedlings.

More Reports of Moth Captures--Armyworms and Black Cutworms
A lot of people throughout the Midwest have reported captures of armyworm and black cutworm moths all spring. Intense captures of black cutworms have been reported from many locations. Any corn that has emerged should be monitored carefully now for black cutworms and signs of their injury. The same will hold true for corn that will be planted soon.

Bean Leaf Beetles Are Active
Several entomologists have reported finding bean leaf beetles recently active in alfalfa and clover fields and in noncrop areas. Although very few soybeans have been planted yet this year, any early-planted fields should be monitored very carefully as soon as plants emerge. These early fields will be "magnets" for bean leaf beetles.

This article includes a description of the bean leaf beetle, its life cycle, and economic thresholds; it also discusses how the bean leaf beetle can transmit bean pod mottle virus.

Alfalfa Weevils Creating Headaches in Many Fields
By now it's no secret that alfalfa weevils have caused more damage to alfalfa this year than in several recent years. They survived the mild winter conditions quite well, and they seemed to come on early and strong in most areas. Alfalfa weevils have been active in southern Illinois for a few weeks.

Don't Confuse Clover Leaf Weevils with Alfalfa Weevils
Although clover leaf weevils rarely cause economic damage in alfalfa in Illinois, their presence should be noted because they can be confused with alfalfa weevils. It is important not to confuse the two species; including counts of clover leaf weevils with counts of alfalfa weevils could inflate the estimate of the alfalfa weevil population.

A Few Insect "Thumbnail" Reports
This article contains a few brief reports of occurrences of a few insects in Illinois or elsewhere in the Midwest. Insects mentioned include the European corn borer moth, corn leaf beetles, wheat curl mites, and bird-cherry oat aphids.

Now Is the Time to Sample for Plant-Parasitic Nematodes
This article addresses the following questions:

Who should take soil samples?
What are the symptoms of PPN infestation?
Where should soil samples be taken?
How should soil samples be collected?
Why should you sample in the spring?
Where should you send the samples for analysis?

The Conditions Are Right for Foliar Diseases of Alfalfa in Illinois
The recent wet and cool weather in Illinois, along with frost in parts of the state, following a period of rapid growth of alfalfa, is creating favorable conditions for foliar diseases. Alfalfa foliar diseases are often common at this time of the year, especially in the lower part of the plant.

This article includes a short summary of some common fungal leaf spot diseases of alfalfa, including spring leaf spot and black stem, lepto leaf spot, and common leaf spot.

Weeds on the Horizon
This past winter, at Extension meetings throughout the state, we conducted a survey titled "The Illinois Invasive Weeds Survey." This survey was designed to determine what weeds are thought to be the most prevalent throughout the state and to give us a head start on what may be some of the emerging weed problems in the future. This article presents the results of that survey.

Weed Control Options in Corn After the Preemergence Application Window
Many growers and applicators will soon be left with the decision of what to do for weed management strategies on those acres that won't be treated until the corn crop has emerged. The first option is to use the soil-applied herbicide program that was initially planned, and the second option is to switch to a total postemergence strategy. This article discusses both options.

Corn Planting Delays
This planting season is shaping up as one of the more difficult ones of recent years, at least in Illinois and states east of here. Besides the slow progress to date, many fields are quite wet; drying rates have been slow due to cool temperatures; and the planting progress has been very uneven, with some areas mostly planted and others yet to start.

In most cases, we probably want planting to be the first operation done as soon as soil conditions allow, with nitrogen and herbicide application done afterward so that planting is not further delayed. But we also need to be reasonable in our approach to difficult weather conditions, recognizing that very good yields are possible even when corn is planted in May.

Nitrogen Loss for 2002
The warmer-than-normal winter, coupled with a wet spring, has many wondering whether nitrogen loss is or will be greater than normal for the 2002 crop year. Fortunately, research conducted at the University of Illinois over a number of years has provided a data base on which to make an informed decision about the amount of N loss that has occurred or that might occur in the next few weeks.

The bottom line is that most producers need not worry about N loss up to this time. They can save that worry for later in the season if soils become saturated.

Plant, Then Sidedress
Wet soils this spring have delayed most field activities, particularly corn planting. Don't delay planting to wait until nitrogen fertilizer has been applied. Plant, then sidedress.

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 and west-central Illinois.

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

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