The army cutworm is the immature form of ''Euxoa auxiliaris''. The adult moth is called a "miller moth" because of the fine scales on its wings that rub off easily and remind people of the dusty flour that covers the clothing of a miller. 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'', known as downy brome, drooping brome or cheatgrass, is a winter annual grass native to Europe, southwestern Asia, and northern Africa, but has become invasive in many other areas. It now is present in most of Europe, southe ...

(''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 Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

(''Artemisia'' spp.). The miller moth is a seasonal nuisance in the spring in states including

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

, Wyoming,

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, ...

and

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to ...

, 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.

Location

''Euxoa auxiliaris'' is commonly found in the Western section and prairies of the United States. They are known to travel to

alpine climate Alpine climate is the typical weather (climate) for elevations above the tree line, where trees fail to grow due to cold. This climate is also referred to as a mountain climate or highland climate. Definition There are multiple definitions of ...

regions in late June and early July where they feed at night on the nectar of wildflowers. Army cutworms are one of the richest foods for predators, such as

brown bear The brown bear (''Ursus arctos'') is a large bear species found across Eurasia and North America. In North America, the populations of brown bears are called grizzly bears, while the subspecies that inhabits the Kodiak Islands of Alaska is kn ...

s, in this ecosystem, where up to 72 per cent of the moth's body weight is fat, thus making it more calorie-rich than elk or deer. This is the highest known body fat percentage of any animal.

References

Euxoa Agricultural pest insects Moths of North America Moths described in 1873 {{agri-stub