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No. 11/June 07, 2002

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Are We Experiencing "Delayed" Insect Problems?
With so much focus on the less-than-optimal weather and poor crop growing conditions, it's possible that some insect problems may not have been detected.

The crummy appearance of some of the corn may have masked some injury being caused by subterranean insects, primarily white grubs and wireworms, but also cutworms. The cool weather has enabled some of these insects to stick around a little longer than usual. Warmer weather has encouraged more rapid growth of corn, so people should now take note of any corn plants that "just don't look right."

Black Cutworms Causing Economic Damage in Some Areas
Within the past week and a half, we received several reports of damage caused by black cutworms. Some of the cutting has occurred above ground, but observers have indicated that cutting below ground is common.

Crane Flies Found in Some Fields
Kevin Black with Growmark in Bloomington has indicated that he has received more than a "typical" number of reports of crane fly larvae in some fields this spring. Given the amount of rain that has fallen this year and crane flies' proclivity for wet conditions, this is not surprising. However, crane fly larvae are not pests of corn, so it's very important that they not be mistaken for cutworms.

First Flight of European Corn Borer Moths Well Under Way in Central Illinois: Egg Masses Detected in Southern Illinois
This article is devoted to providing some answers to questions concerning the first generation of this perennial pest.

How did the overwintering population of corn borers "stack up" in 2001 compared with previous years?
What areas of the state are most at risk to economic infestations of European corn borers this spring?
Why are early-planted cornfields most at risk to the first generation of borers?
What are corn borer "action sites"?
Is treating an action site with an insecticide a good idea to prevent corn borers from causing problems in my cornfields?
What's the best approach to scout a field for first-generation corn borers?
Many plants within my field have whorl-feeding injury, but I can't find any borers. Should I treat anyway?
When will corn bores begin to tunnel into stalk tissue?
If I find European corn borer larvae within the whorls of Bt plants, does this mean that the Bt corn is not working?

Enormous Numbers of Southwestern Corn Borer Moths Captured in Southern Illinois
Ron Hines has reported captures of extremely high numbers of southwester corn borer adults in traps in Massac and Pulaski counties.

Although first-generation southwestern corn borers usually don't cause much, if any, economic damage in Illinois, the situation in southern counties this year is anything but usual. If these borers survive well through their first generation, we may have a real battle on our hands during the second generation.

Corn Rootworm Larval Hatch Anticipated
Due to the excessive precipitation in May and subsequent planting delays, corn rootworm larvae may hatch into fields with very small root systems. In east-central Illinois, severe root injury may result in many of these first-year cornfields.

North Central Region Technical Research Committee (NCR-46) on Corn Rootworms Offers Support for a Conditional Registration of Corn Rootworm Transgenic Event
In late May of 2002, a technical committee of research and extension entomologists, along with selected cooperators, sent a letter to the U.S. Environmental Protection Agency offering their support for a conditional registration of a transgenic event (MON 863) that could serve as one of several management tactics for corn rootworms.

Stalk Borers Are Active in Some Areas
Degree-day accumulations suggest that stalk borers have moved into cornfields in central Illinois and are beginning to move into cornfields in northern Illinois. According to reports from the field, such is the case.

Bean Leaf Beetles Are Gnawing Away in Early-Planted Soybeans
Not surprisingly, bean leaf beetles are abundant in early-planted soybean fields. Where a lot of soybeans went into the ground at about the same time, bean leaf beetle populations are "diluted" over the area. However, in areas where some fields were planted early and other fields have just been planted or have yet to be planted, bean leaf beetle densities are quite high in the early-planted fields.

Callisto Advisory
We recently received a product advisory regarding the herbicide Callisto. This article includes part of the text from that advisory.

Notice of Ergot in Grasses
Weather conditions this spring have been extremely conducive for the development of ergot. Ergot is a fungal disease of the seed head and can infect around 200 species of wild and cultivated grasses and open-pollinated small grains such as rye.

Infested grasses are a serious concern in a pasture situation because the fungus produces a very potent mycotoxin. The mycotoxins are a serious health risk not just to animals but to humans as well.

Powdery Mildew of Wheat
Over the past 2 weeks powdery mildew has been particularly evident throughout the state. This article includes a description of the disease and suggestions for treatment.

Anthracnose Seedling Blight of Corn in Illinois Fields
Anthracnose is somewhat of an oddity in the corn disease world because it is one of the few important diseases in the Midwest that can be a problem from the seedling stage of growth to harvest. The anthracnose pathogen can cause leaf blight of seedlings as well as late-season leaf blight, root rot, stalk rot, and top dieback, and it can infect stalks systemically. Incidence of this disease has been reportedly increasing in Illinois (particularly the late-season phases), and it should be watched for. In some parts of Illinois, conditions are or may soon be favorable for the seedling leaf blight phase of anthracnose.

University of Illinois Weed Science Field Day
We invite you to make plans to attend the annual University of Illinois Weed Science Field Day, to be held at the Crop Sciences Research and Education Center (CSREC) on June 26. Registration begins at 7:30 a.m., and the field tour kicks off at 8:30 a.m. The tour will provide ample opportunity to look at research plots and participate in some short field presentations.

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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