Pale western cutworm

Definition

A noctuid moth species (Agrotis orthogonia) whose larval stage is a significant agricultural pest of small grains and row crops in the arid and semi-arid regions of western North America. The common name refers to the pale, almost whitish coloration of the mature larva, which distinguishes it from darker cutworm species, and to its geographic restriction to dry western habitats ranging from southern Canada through the Great Plains to California.

Etymology

English compound: 'pale' for the larva's light coloration; 'western' for its North American range west of the Great Plains; 'cutworm' for the larval habit of cutting seedling stems at or below the soil surface.

Example

In Montana wheat fields, pale western cutworm outbreaks are most severe during drought years when natural enemy populations decline and larvae concentrate in irrigated crop edges.

Synonyms

• Agrotis orthogonia

Related Terms

• Cutworm
• Noctuidae
• Agrotis
• Army cutworm
• dingy cutworm
• economic entomology
• Integrated Pest Management
• larval instar

Usage Notes

The common name properly applies to the species Agrotis orthogonia, not merely to individual larvae. In agricultural contexts, specialists distinguish it from other 'western' cutworms by its pale coloration and preference for drier habitats. The species is univoltine, with larvae active in early spring when they pose the greatest threat to emerging crops. Misidentification with the army cutworm (Euxoa auxiliaris) or dingy cutworm (Feltia jaculifera) is common in field surveys; dissection or molecular confirmation may be required.