Agrotis ipsilon

Definition

A cosmopolitan noctuid moth (family Noctuidae) commonly known as the black cutworm, dark sword-grass, or ipsilon dart. Adults are medium-sized, dull brownish-gray moths with distinctive black forewing markings shaped like the Greek letter upsilon (Υ) or letter "Y," from which the specific epithet derives. The larvae are polyphagous cutworms that sever plant stems at or below the soil surface, causing significant economic damage to vegetables, field crops, and turfgrass worldwide. This species exhibits high migratory capacity and broad climatic tolerance, contributing to its status as a major agricultural pest across temperate and tropical regions.

Etymology

Latin Agrotis (field or country) + Greek ipsilon (Υ, the letter Y), referring to the diagnostic wing markings

Example

In Midwestern cornfields, Agrotis ipsilon larvae typically emerge in spring to cut young maize seedlings, with economic thresholds often set at 2–3% stand reduction; pheromone trapping of migrating adults helps time preventive insecticide applications.

Synonyms

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

Related Terms

• Cutworm
• Noctuidae
• Agrotis
• larval feeding damage
• Economic threshold
• pheromone trap
• polyphagy
• stem borer

Usage Notes

The common name "black cutworm" is widely used in agricultural extension literature, though "greasy cutworm" refers to the larva's smooth, shiny appearance. The species is frequently confused with Agrotis segetum (turnip moth) and Agrotis exclamationis (heart and dart) in Europe; accurate identification requires examination of genitalia or wing pattern details. The subspecies A. i. aneituma occurs in parts of the Pacific region.