When the larvae mature, they burrow an inch or two into the soil and transform to brown, hard-shelled pupae from which the adult moths will emerge. Armyworm larvae have different coloration depending on the species, available food, and genetic variation. Generally, they are a green or brown color with various other markings. When populations are high, the moths of the armyworm may be found in abundance around lights at night. The moths have a wingspan of about two inches and a rather nondescript color pattern.
Armyworms attack many different kinds of plants.
When food plants are scarce, they will eat almost anything green. The preferred host plants are corn, small grains, and grasses, but they also seem to enjoy sweet and Irish potatoes, beans, turnips, clover, spinach, cucumbers, tomatoes, cowpeas, and cabbage. Plant stems and large leaf veins are usually not consumed unless the larvae are near starvation. Outbreaks of armyworms may need to be controlled when plant damage begins to be excessive. Regular inspection of areas where armyworms are likely to be found is advisable so that treatment can be applied before serious plant damage occurs and the larvae mature.