Black cutworm

Black cutworm

Black cutworm (BCW) is the most damaging cutworm species in corn. Larvae sever plants from their roots, near the soil line, thereby reducing crop stands and lowering yield. Damage from cutworms is often most evident in no-till or weedy fields, especially in poorly drained areas. Adult moths blow into a field, lay eggs and produce a hatch of young larvae that cause major losses in young crops.

Traditional control programs include in-furrow insecticide applications, seed-applied insecticides, scouting and rescue spray programs. Seed-applied insecticide performance decreases with larger larvae, and soil-applied insecticides are not always successful either. Scouting and spraying do not always catch BCW, because larvae often burrow into the soil during the day and older cutworm larvae feed on the stem underground.

Black cutworm geography map

Black cutworm damage

Damage

BCW damage is most often evident in weedy fields where weeds were removed just prior to planting. Larvae feed on developing corn seedlings. Early instars feed on developing leaf tissue resulting in small holes. Older larvae will cut seedlings at or just below the soil surface, and occasionally tunnel up a plant. Larvae also may strip leaves from plants, although this climbing behavior is not common. Plants that are cut below-ground and larger plants that have been tunneled usually do not recover.