PEST PROFILES: MOTH AND BUTTERFLY CATERPILLARS
Picture of Walnut Caterpillar

Click on image to view larger.
Walnut caterpillar

Description:
Adults are brown and tan with a dark region on the body behind the head and wavy, dark lines across the front wings (2 inch span). Larvae are reddish brown to black with white markings and long white hairs. Large larvae are conspicuously fuzzy and may grow up to 2 inches long. There are several common species of Notodontidae.

Damage:
An occasional but serious threat to pecan and other trees and shrubs. Young larvae skeletonize leaves, while older larvae feed on the entire leaf. Isolated trees are more subject to attack. They can rapidly defoliate ornamental and orchard trees if not controlled. In previous years, almost all of the native pecan trees in certain areas of Texas were defoliated by walnut caterpillars.

Life cycle:
Overwinters as pupae in soil at base of host tree. Females deposit about 300 eggs on the underside of a leaf. Larvae live gregariously and often move in a group to the tree trunk to molt. There are 2 generations per year with the more numerous second generation causing more damage.