No. 09/May 24, 2002|
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|IN THIS ISSUE:|
|Insects and Cool, Wet Weather--Abbreviated Comments|
Corn and soybean planting has proceeded at a snail's pace in many areas of Illinois, and corn that has emerged is growing very slowly. The slow-growing corn has been a prime target for some subterranean insects, such as white grubs and wireworms, in some areas of the state.
|Soil Degree-Days and Rootworm Development|
The words "degree-day accumulations" don't mean much when temperatures are abnormally cool for this time of year. Although we suspect that rootworm larvae have hatched in southern Illinois and have begun hatching in central Illinois, no one has reported finding them yet.
|Stalk Borers Could Be Moving Into Cornfields in Some Areas|
It seems almost silly to talk about stalk borers under the circumstances, but many farmers in northern counties, where quite a bit of corn has been planted, have had enough experience with stalk borers to know that watchfulness is worthwhile. Although stalk borers can be very difficult to manage, timely field scouting can forestall significant problems.
This article discusses the life history of stalk borers, a description of the insects and the injury they cause, and suggestions for scouting and management.
|A Few Insect "Thumbnail" Reports|
In this strange season, maybe a few "thumbnail" reports of insects are all we need. Most farmers have a lot more pressing issues on their minds. This article presents a quick overview of a few reports we have received. Insects mentioned include armyworms, black cutworms, white grubs, alfalfa weevils, and potato leafhoppers.
|Scab of Winter Wheat|
The very wet weather has kept many of you from slogging through the fields on wheat scouting missions; however, the weather has been very good for scab to develop. Now is the time to look for head scab in fields.
This article describes the disease's symptoms, the disease cycle, the effects of mycotoxins, and university recommendations for the management of scab.
|Soybean Cyst Nematode HG-Type Test|
Everyone who has soybean cyst nematode (SCN) knows that there are many good SCN-resistant varieties available. Everyone has also heard horror stories of resistant varieties that didn't work. Believe it or not, it is possible for a resistant variety to have good resistance that fails in certain fields.
The SCN race test will soon be replaced by a new test, called the HG-type test. With this test, we can recommend resistant soybean varieties that have effective resistance to the SCN population that is present in the field.
|Diseases of Corn Seed and Seedlings|
Disease is likely to be a minor problem compared to environmental stresses in most areas, but it may be important in some fields. This article briefly describes some of the pathogens and diseases that may affect seedling corn.
The article includes a list of symptoms that may indicate problems with corn seed or seedling disease in a field, symptoms of foliar seedling infections, and a list of treatments.
|Options for Postemergence Grass Control in Corn|
In the next couple of weeks, grass control in corn could be a major challenge for some producers in the state. What options do we have for postemergence grass control in corn?
When making a decision on what postemergence grass control option you may want to use, there are a number of things to consider, such as the type of corn hybrid planted, the grass species that you are trying to control and what sizes they are, the environmental conditions at the time of the postemergence application, and adjuvant selection.
|Corn Replanting and Herbicide Considerations|
While there are many agronomic considerations associated with replanting, some weed control/herbicide issues should also be considered.
This article includes information about hybrid selection and rotating to other crops. It also discusses the issue of planting soybean into atrazine-treated fields; while this is not a recommended procedure, the article offers some practices for consideration.
|Corn Still a Worry, Soybean's Turn Next|
If planting can get under way at a good pace in most of the unplanted areas within the next week, we think that most producers can probably still plant the hybrid they had planned to plant a month ago. Exceptions might be hybrids relatively late for the area and perhaps hybrids that are known not to do very well under stress.
While it is tempting to try to "finesse" soybean management to compensate for late planting, we do not see evidence to support making many changes.
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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