The armyworm cannot survive Colorado winters.
Armyworm moths migrate into Colorado in early summer.
Larvae feed at night and on cloudy days and hide under crop debris during sunny periods. Armyworms have five stripes, three on the back and two on the sides, running the length of the body. In Colorado, it is mostly a pest of corn and spring grains, with only occasional infestations in winter wheat. Outbreaks are sporadic and unpredictable, so management options are limited to the use of insecticides. The armyworm cannot survive Colorado winters.