Issue No. 6/April 29, 2005
Time for Early-Season Corn Insect Pests
Guidelines are discussed for evaluating symptoms of possible injury to corn by early-season insects, including grape colaspis, white grubs, and wireworms. Injury can result from noninsect sources as well, so identifying the responsible factor is key.
Quick Status of Soybean Aphids
Early observations of soybean aphids on buckthorn plants in northern Illinois don't yet offer conclusions; stay alert for further developments.
Corn Seed and Seedling Diseases
Early planting followed by cool and/or wet conditions in April and May can favor seed and seedling diseases. Disease symptoms and other implications are outlined.
Factors That Increase the Likelihood of Corn Injury
The variety of factors that influence whether a corn crop will exhibit injury symptoms after herbicide application are discussed. Unless weed pressure necessitates immediate action, producers may want to consider waiting to let corn recover from the stress of cold air temperatures before applying postemergence herbicides.
Horseweed Control Issues with Glyphosate
Concern is growing in Illinois about resistance to glyphosate among populations of horseweed. The development of resistance is explained along with options for managing glyphysate-resistant horseweed both before planting soybean and after emergence.
Horseweed (Marestail) Identification and Biology
The life cycle and growth characteristics of horseweed are detailed.
Interactive Web Page for Glyphosate Formulation Comparisons
A new Web page lets users determine equivalent application rates of various glyphosate-containing products.
Return to "Normal"
The effects of freezing and near-freezing temperatures on corn development are outlined.
Reports are provided this issue for east-central, northern, southern, and west-central Illinois.