Evaluating Artificial Infestations of Black Cutworms

Seedling corn plants enclosed by aluminum barriers were manually infested with varying numbers of laboratory-reared larvae of the black cutworm, Agrotis ipsilon (Hufnagel ) to determine extent of damage caused by this insect One 4th-instar larva per 4 plants damaged 24.5% of corn, 1 per 2 plants damaged 23.6%, 1 per plant damaged 31.7%, and 2 per plant damaged 68.7%. Regrowth of damaged plants varied with stage of development, but plants that are cut off can usually be considered of little value as ear-producing plants.