Black cutworm

Definition

A common name for Agrotis ipsilon, a noctuid moth whose larvae are destructive agricultural pests. The larvae feed at or below the soil surface, severing seedlings at the stem base—hence "cutworm"—and can destroy stands of corn, soybeans, turf, and vegetable crops. The species is cosmopolitan, with multiple generations per year in warm regions, and exhibits strong attraction to high-moisture, weedy fields where females oviposit.

Etymology

"Black" refers to the dark coloration of the mature larva; "cutworm" describes the larval habit of cutting through plant stems at or near the soil line.

Example

In the Midwestern United States, black cutworm larvae (Agrotis ipsilon) often migrate northward on spring storm fronts, arriving in cornfields just as seedlings emerge and causing characteristic stand reduction with wilted, severed plants.

Synonyms

• dark sword-grass
• ipsilon dart
• greasy cutworm
• floodplain cutworm

Related Terms

• Cutworm
• Agrotis
• Noctuidae
• economic entomology
• seedling pest
• larval migration

Usage Notes

The name "black cutworm" is applied specifically to Agrotis ipsilon and should not be confused with other Agrotis species (e.g., the variegated cutworm, A. subterranea, or the dingy cutworm, A. vancouverensis). The larva is smooth, greasy-textured, and dark gray to black; identification to species requires examination of adult genitalia or larval mandible structure. In integrated pest management, pheromone trapping of adults predicts larval outbreaks 2–3 weeks later.