Forest Pests: Insects, Diseases & Other Damage Agents

Variegated Cutworm (Peridroma saucia)

From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance- The larvae occasionally kill emerging nursery stock and cuttings planted in old farm fields.

Look For: Seedlings or cuttings severed near the ground line. Missing foliage or foliage partly buried near the seedling or cutting. Pale gray to dark brown larvae up to 1½ inches long. Larvae feed on the plant at night and hide in the soil near the plant during the day.

New shoots injured by cutworm.

Biology- The female moth deposits eggs on stems, leaves, lower branches, and twigs. Newly hatched larvae burrow into the soil and begin to feed soon after. There may be four generations per year, but spring feeding causes the most damage.

Monitoring- Inspect young trees for damage in the spring. Search for larvae in the soil if you suspect cutworms. Control immediately if damage exceeds 10 percent.

Control:

• Apply a commercial preparation Bt (Bacillus thuringiensis) to the foliage.
• Apply a chemical insecticide recommended for cutworms in the late afternoon or early evening.