Behavior of Neonate Imported Cabbageworm Larvae (Lepidoptera: Pieridae) Under Laboratory Conditions on Collard Leaves with Glossy or Normal Waxi

Abstract

Movement and feeding of newly-hatched imported cabbageworms, Pieris rapae (L.), on the upper and lower leaf surfaces of collard plants with glossy and normal waxes were monitored using a videocamera. During the 50-min observation period, more of the larvae fed when placed on the lower surface of leaves with normal wax (50 to 68%) than on the upper surface (23 to 32%), or on either upper (27%) or lower (16%) surfaces of leaves with glossy wax. A larger portion of the larvae moved at least 1 mm on glossy leaves than on normal leaves, and they moved farther during the observation period on glossy than on normal leaves, and on the upper leaf surface compared to the lower leaf surface. The failure of a large proportion of the larvae to begin feeding on either surface of leaves with glossy wax is likely to be an important factor in the resistance to imported cabbageworms observed in the field.