Black Cutworms on Sweet Corn
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Black cutworms (Agrotis ipsilon) are occasional pests of sweet corn and can cause considerable stand loss in localized areas of a field.Black cutworms are active on corn from plant emergence through mid-June. They are more likely to be found in fields with a history of cutworm damage, those planted under reduced or no-tillage practices, or those with poor drainage. Late planting; low, damp areas of the field that drain poorly; fall or spring weed growth; and the amount of surface residue influence the potential for cutworm infestations. The cutworms are light gray to nearly black with a faint, narrow stripe down the middle of the back. The skin appears to be greasy and contain tiny granules. Larvae can reach 1¾ inches long when full grown and will be coiled in a compact “C” when uncovered. Cutworms are active at night, feeding on leaves when small and on cutting plants as they grow. Symptoms are cut, wilted, or missing plants. Infestations usually develop on early-season weed growth.
A black cutworm attacking corn seedling.
(Photo: UK Vegetable IPM Team, University of Kentucky)
Adult black cutworm moth
(Photo: UK Vegetable IPM Team, University of Kentucky)
Management:
- Early land preparation and good weed control will help reduce cutworm problems.
- It is important to watch the field closely for cut plants. Early detection means an insecticide can be applied before serious damage occurs.
- Seed treatments can help reduce the number of cut plants.
