Armyworms have four distinct life stages: egg, larva, pupa, and adult.
After mating at night, the female armyworm can lay 100-200 eggs, which they attach to leaves. Newly hatched larvae feed on the leaf and eventually lower themselves to the turf to feed by spinning a silken thread.
Most defoliation will occur in the larva stage, where they will quickly consume more than 93% of the total foliage they will eat over their entire life span. Armyworm caterpillars will feed for two to four weeks before pupating in the soil. Fully developed moths appear about two to four weeks later.