Whitemarked Tussock Moth
WHITEMARKED TUSSOCK MOTH
Orgyia leucostigma (J.E. Smith)
A Guide to Recognition and Habits in Alabama
L.L. Hyche, Associate Professor
Department of Entomology
Range and Hosts
This moth is widely distributed throughout eastern North America, as far west as Texas and Colorado in the United States. The larvae are known to feed on foliage of a wide variety of trees, both conifers and hardwoods. Hardwood hosts include basswood, maple, sycamore, apple, oak, poplar, willow, and elm.
Life Cycle, Description, and Habits
The insect overwinters in the egg stage. (Photo 1) Eggs hatch in the spring, usually April in Alabama. Young larvae skeletonize leaves; later-stage larvae are solitary feeders and consume whole leaves. Larvae become fully grown in five to six weeks; in the Auburn vicinity, mature larvae have been found in early May.
The full-grown larva (Photo 2) is around 35 mm long. The head and shield on the segment behind the head are red. There are two long black pencils of hairs on the first segment of the thorax that project forward. A single black hair “pencil” arises from the eighth abdominal segment and projects upward and rearward. The back is mostly black and the sides yellow, cream, or grayish. There is an erect brushlike tuft of white or yellowish hairs on each of the first four abdominal segments, and a conspicuous red dot on segments six and seven. Fully grown larvae construct loose tan-gray cocoons (Photo 3) on the underside of branches or in bark crevices and pupate. Moths emerge in about two weeks.
The male moth (Photo 4) is gray with wavy lines across the front wings; wingspan is 25-30 mm. Antennae are conspicuously plumose. The female moth (Photo 5) is wingless, grayish white to light brown, and 12-14 mm long. Females lay eggs on cocoons (Photo 1 and Photo 4) from which they emerged, then die. Eggs hatch to begin a new generation. There appears to be two generations (a third may possibly occur) per year in Alabama, and larvae can generally be found from April until fall.
Occurrence and Damage
The whitemarked tussock moth caterpillar is commonly found in Alabama feeding singly on foliage of small scattered shade, ornamental, or orchard-type trees. Historically, populations have been low and damage correspondingly minor. However, the species has the potential to occur in sufficient numbers to reduce the aesthetic value of ornamental trees. The caterpillar possesses “nettling” hairs, and contact with these could cause some mild skin reaction.