Armyworms are actually the caterpillar life stage of a moth.
Their eggs masses which may contain several hundred new worms are deposited on or near plant foods. Each female may deposit several of these clusters. The caterpillar that hatches from the egg is only about one-eighth inch long, but when it is full grown, it reaches a length of about two inches. The caterpillars, usually feed at night and hide in plant litter just above the soil surface during the day. These moth larvae chew off the grass blades above the soil surface.