Caterpillars have chewing mouthparts. Adults have siphoning mouths. Young larval stages feed close together, often grazing on the outer (epidermal) layer of cells on the underside of leaves. They may spin a light web over the foliage. Older, larger caterpillars feed alone and consume leaf tissue that can result in complete defoliation of host plants.
Consult the Vegetable IPM Web Site for recommended controls of this pest.