Individual female moths can lay over 1,000 eggs in their lifetime, but the average is probably much lower. Color of mature larvae ranges from bright green to purplish green to blackish. The most common phase is light olive green with a darker strip down the back and a paler stripe along each side. Cocoons have been reported but apparently are rare. The pupal stage is reported to average approximately 17 days.
Forewings have a lighter spot near the center.
Hindwings are paler with darker borders, however, a light band occurs at the wing edges. In Hawaii beet armyworm caterpillars seldom migrate in armies as do other species of armyworms. Management of broad leaf weeds and rapid disposal of crop residues after harvest are the most important practices. Biological Control Little is known about the occurrence and importance of natural enemies in Hawaii. Frontina archippivora is known to parasitize the pest, but its impact on control is unknown.