Salt-marsh Caterpillar, Estigmene acrea (Drury)
The salt-marsh caterpillar frequently is a pest on forage crops such as small grain and alfalfa. The female deposits eggs in clusters on the underside of the leaves of the host plant. The caterpillar is clothed with long black, brownish or yellowish hairs and is often called "woolybear." The full-grown worm is about 2 inches long. Winter is passed either in the larval or pupal stage. There may be as many as four generations annually.