Common Name: Armyworm
Scientific Name: Noctuidae: Pseudaletia unipuncta
Status: pest of grasses, small grain crops, and corn
Damaging Stage: caterpillar

Biology: Armyworm adults are light brown-gray moths with a conspicuous white spot about the size of a pinhead on each front wing. The wing span is approximately one inch across.

Armyworm eggs are laid in masses and are greenish white. Often, many hatch at the same time, which produces "armies" of these caterpillars. When such populations exist, they appear to march in masses, devouring all of the plants in their path. Full-grown caterpillars are gray and are approximately 1� inches long. White, orange, and dark brown stripes run the length of the abdomen on each side. The head capsule is a light orange and can sometimes be mottled.

Injury: Armyworms can be serious pests on a number of grasses, small grain crops and corn. However, they also feed on and sometimes damage alfalfa, beans, clover, flax, millet, and sugarbeets. Young caterpillars skeletonize leaf blades while older caterpillars can consume the entire leaf.

Action Threshold: If crops are showing signs of armyworm damage, it is usually too late to control the caterpillars. It is important to catch this pest when the caterpillars are still small and not feeding extensively. Field scouting for armyworms includes examining leaves, severed leaf materials and the base of plants. When 25% of plants are being attacked, control methods should be considered.

Management: Diseases, insect predators, and birds can often keep armyworm populations under control. In the case of a serious outbreak, chemical control methods are extremely effective.