Issue No. 6, Article 12/May 5, 2006
Delayed Applications of Soil-Applied Corn Herbicides
Soil-applied herbicides continue to be widely utilized for weed management in Illinois cornfields. Most of the corn acres that were scheduled to be treated with a soil-applied herbicide were treated before planting or before corn emergence. It is likely, however, that some cornfields were planted before the herbicide was applied, and the crop has now emerged. Can a soil-applied corn herbicide be applied after the crop has emerged? Many, but not all, soil-applied corn herbicides can be applied after corn emergence. Not all of these herbicides will control emerged weeds, so additional management procedures (such as the use of a rotary hoe or the addition of a herbicide that has postemergence activity) may be needed. We caution farmers about the potential for enhanced corn injury if these products are applied during periods of crop stress, such as stress caused by excessive soil moisture, cool air temperatures, and the like. Table 2 summarizes information about postemergence applications of the more traditional soil-applied corn herbicides. Consult the respective product labels for additional information.
--Aaron Hager and Dawn Nordby