Young larvae move like loopers, arching their body into a loop as they crawl.
Mature larvae of both species may reach 2 inches in length. Entire leaves may be consumed or damage may consist of notches chewed out of the leaves giving them a tattered look. If larvae are moving into the cereal crop from an adjacent crop, some control may be obtained by plowing a deep, wide ditch between the two fields and keeping it filled with water until the migration stops. Parasitized worms can be identified by pulling the larvae apart and looking for the green parasite larvae that pop out. Hyposoter is usually not active in early spring when cereals may be attacked by armyworms but it should be looked for.