Whitemarked Tussock Moth

Photo credit to Dr. Drees.

Common Name: Whitemarked tussock moth

Scientific Name: Orgyia (=Hemerocampa) leucostigma (J. E.Smith)

Order: Lepidoptera

Description: Caterpillars grow to 1-1/4 inch long and is unique in that there are four brush-like tufts or bunches of light tan hairs on the back (top of the first four abdominal segments) and red dots (abdominal segments six and seven). In addition, there is a pair of longer tufts of black hairs (pencil lead-sized tufts called pencil hairs) arising from the front (from the prothorax) and a light-haired one from the back (eighth abdominal segment) of the body. The body is overall cream-colored, has a broad black stripe on the back and a broader gray stripe along each side, and a red-orange head. The male moth is ash gray and the forewing is marked with darker wavy bands, with a wing span of about 1 1/4 inches. Females are white to gray and do not have fully-developed wings.

The pale tussock moth, Halysidota tessellaris (J. E. Smith) lacks the upright tufts of short, light hairs on the first four abdominal segments. Its body is covered with whitish hairs, may have a line of darker hairs along the back, and has pairs of longer hair tufts (pencil hairs) arising from both ends of the body. The sycamore tussock moth, Halysidota harrisii Walsh, which feeds on American sycamore and London plane tree throughout the range of these plants, has white body hair and hair tufts (pencils) on the ends of the body. Several other species of tussock moths occur and, when in high numbers, may damage ornamental host plants. Another notable species in the family Lymantriidae is the gypsy moth, Lymantria dispar (Linnaeus), which was introduced in northeastern America and has been spreading south and westward. Although adult specimens have been collected using sex attractant (pheromone) traps along routes of transportation, larval infestations have not occurred in Texas.

Life Cycle: Winter is spent in the egg stage. Caterpillars hatch from eggs from April to June and develop through several stages (instars) over a period of 30 to 40 days. Caterpillars pupate within grayish cocoons made of silk and larvae hairs on the trunk, branches of the host plant or on nearby objects. Adults emerge in about 2 weeks and mate. Females lay masses of eggs on the surface of old cocoons. There are three generations per year.

Habitat and Food Source(s): Caterpillars have chewing mouthparts. Adults have siphoning mouths. Caterpillar host plants include apple, basswood, elm, maple (Norway, and silver), pear, plums, poplars, rose, sycamore, willow, wisteria and others. The subspecies in the south feeds on live oak, redbud, pyracantha and mimosa. Young larvae skeletonize leaves while older larvae eat all of the leaf surface except for the larger veins.

Pest Status: An occasional but serious threat to pecan, hickory, walnut and other trees and shrubs. It also feeds on oak, willow, honey locust and certain woody shrubs.