Army cutworm

The army cutworm is the immature form of Euxoa auxiliaris. Together with other moths that are locally abundant and that have scales that dislodge from the wings, the adult moth is called a miller moth.

These native North American larvae consume emerging small grains, alfalfa, and canola in the southern Great Plains and southern Canada. Larvae feed above ground at night and usually hide in soil during daylight, but will also feed on cloudy days.

On dry, low elevation rangelands of the U.S. Intermountain West, army cutworms consume exotic cheatgrass (Bromus tectorum) and mustards to produce cheatgrass "die-offs." Within these bare areas, the larvae also defoliate native shrubs including four-wing saltbush (Atriplex canescens) and sagebrush (Artemisia spp.).

The miller moth is a seasonal nuisance in the spring in states including Montana, Texas, Oklahoma, Colorado, Wyoming, New Mexico, and Kansas, as they hatch in the low-lying farmlands, then migrate to higher elevations for the summer. They return as the weather cools but in smaller numbers. They are considered nearly impossible to control through normal pest extermination techniques because a new batch shows up every day as they migrate. With their very small bodies, they enter homes (attracted by the light) in the evening through any available crack or crevice (doorjamb, chimney, etc.) and residents in migration paths report dozens of moths per day entering their homes and garages. However, other than being a nuisance, they are not considered harmful.