Don't Delay Scouting Efforts for European Corn Borers

June 11, 1999
We've had many reports this past week regarding European corn borer infestations in early-planted cornfields. Fields that seemed to support the largest number of corn borers, not surprisingly, included those fields planted in late March or early April. Heat-unit accumulations are mounting rapidly, and projections for stalk boring to begin across central Illinois indicate that fields should be scouted as soon as possible. For most areas across southern Illinois, initial stalk boring activity may have started as early as late May but certainly began in some fields by early June. With recent temperatures in the 90s across much of Illinois, borer development progressed rapidly, and early-planted fields, even in northern Illinois, should be scouted carefully, beginning no later than mid-June. In last week's issue of the Bulletin, we provided many details on scouting techniques, worksheet calculation procedures, labeled insecticides, and corn borer development parameters based on heat-unit accumulations. Please refer to this issue for all the necessary details. The most important piece of information to convey is this: don't delay your scouting efforts. This may be the season where European corn borers come on fast. The bottom line: rescue treatments are not an option once stalk tunneling has begun.--Mike Gray

Author: Mike Gray