The head of the caterpillar is mottled brown, and the body has longitudinal shades of tan-brown, except on the second and third thoracic segments, which are bright green. On the first abdominal segment is a prominent hornlike protuberance (hence the common name), and a smaller protuberance on the eighth abdominal segment. Host plants include apple, elm, aspen, willow, hickory and other broadleaf trees and shrubs.

About the family

Prominents and oakworms belong to the Notodontidae family. Caterpillars have variable color patterns and body texture. Some species are smooth with fleshy humps or projections while others are hairy. Some are cryptically colored, mimicking the edge of a partially eaten, distorted leaf, while others are brightly colored and conspicuous. In some species, when the caterpillars are disturbed, they raise both ends of the body, holding onto the substrate with the four mid-abdominal prolegs and exposing glands that produce irritating acidic chemicals to ward off potential attackers. Caterpillars exhibit both solitary and gregarious behavior. Host plants include a wide variety of trees and shrubs.

IPM1019, new February 2003