Black cutworms continue to cause stand loss to young corn across the state. Many problems have been associated with weedy fields or no-till fields but economic damage also has occurred in clean, conventionally tilled fields. On rare occasions, the cutworms are damaging corn that is too large to be completely cut by the insects. Tracy Cameron, agronomist at Crestland Co-op, and I examined a field in Union County last week where late-stage larvae were drilling into the side of six-leaf corn or climbing plants and cutting the leaves out of the whorl. The drilling was mostly below the soil surface, hitting the growing point and causing the plant to wilt. Plants will not recover from this type of injury. On some plants the cutworms were climbing into the whorl and cutting the top out of the plant (see photograph). These plants should recover from this injury because the growing point is not damaged.
|Corn whorl cut by black cutworm.|
My recommendation is that cornfields that are still younger than the five-leaf stage should be scouted for black cutworms and appropriate rescue insecticides should be applied if necessary to prevent stand loss.
This article originally appeared on page 121 of the IC-486(15) -- June 25, 2001 issue.