During the latter half of the week of May 3, we received numerous reports of significant levels of damage caused by black cutworm larvae. All of the reports we received came from a band of counties in south-central, central, and east-central Illinois--Christian, Coles, Douglas, Edgar, Fayette, Macoupin, Montgomery, Moultrie, and Shelby counties. The level of damage in many fields exceeded 5% cutting, so insecticide applications were warranted. In some fields, the damage was severe enough that the farmer decided to replant.|
Although reports of severe damage by black cutworms are not widespread beyond the aforementioned band of counties, farmers throughout Illinois should inspect cornfields for signs of cutworm injury. Rapid growth of corn will allow many fields to escape severe cutworm damage. However, black cutworm larvae can eat several small corn seedlings, and timely scouting is the only way to detect the problem before it's too late.
A table with suggested "rescue" treatments for black cutworms was provided in last week's Bulletin (issue no. 11, June 7, 2002). I also made some comments about controlling black cutworms when the soil is dry and crusted. Because several people have observed these conditions, you should do everything necessary to enhance control if cutworms seem to be feeding primarily below ground. If you need some reminders about scouting, including information about determining instars and amount of time black cutworms will feed, refer to the article in issue no. 4 (April 19, 2002) of the Bulletin.--Kevin Steffey