True armyworm larvae are being found across New York State. This
native species does not overwinter in NY but fly north from southern states in the spring. Armyworm moth migrations are somewhat sporadic,
cyclic from year to year and difficult to predict. True armyworms are
primarily a pest of plants in the grass family: forage / pasture
/grasses (& lawns), small grains and corn.
Note: Under hunger stress true armyworms will also attack some legumes and other plants. Moths lay their eggs on weeds and/or grasses along field margins, on leaves of corn, or on small grains. Larvae hatch about a week later and develop over approximately a 3 week period, feeding mostly at night.
Commercial field crop situations at risk for armyworms are:
True armyworm larvae appear smooth, cylindrical, pale green to brownish when they are still small. Mature larvae are smooth and marked with two orange, white-bordered strips on each side. Larvae range in size from 1/8 inch to 1 1/2 inches long (Information compiled by Schuyler County Cornell Cooperative Extension).
True Armyworm (aka Common armyworm) Alert (2012), Cornell University NYS Integrated Pest Management Program
Second Generation Armyworm is here (2012), Cornell University NYS Integrated Pest Management Program
Purdue University Field Crops IPM page discusses several species of Armyworm prevalent in Indiana, how to distinguish the Fall armyworm larvae from several other species, and includes sampling methods and IPM guidelines.
This University of Illinois Extension page on True Armyworm (Mythimna unipuncta Haworth) covers identification, life cycle, discovery, and management practices.
Last updated January 11, 2021