Health Protection, Southern Region
Anisota senatoria (J. E. Smith)
Anisota virginiensis (Drury)
Anisota stigma (Fabricus)
Importance. - These oakworms occur throughout the eastern United States. They are voracious feeders, and where abundant, quickly
strip the trees of their foliage. Since defoliation takes place in late summer to fall, however, forest stands of white and red oak are generally able to survive with
only minimal growth loss or crown dieback. The greatest damage is the aesthetic impact and nuisance the caterpillars create in urban areas.
Identifying the Insect. - The larvae of the orangestriped oakworm are black with eight narrow yellow stripes, the pinkstriped oakworm larvae
are greenish brown with four pink stripes, and the spiny oakworm larvae are tawny and pinkish with short spines. Larvae are about 2 inches (50 mm) long and have a
pair of long, curved "horns". The adult moths are a similar yellowish red, with a single white dot on each of the forewings.
Identifying the Injury. - Young larvae feed in groups, skeltonizing the leaf. Later they consume all but the main veins and usually defoliate
one branch before moving onto another. Older larvae are less gregarious and can be found crawling on lawns and the sides of houses.
Biology. - Adult moths appear in June and July and deposit clusters of several hundred eggs on the underside of leaves. The eggs
hatch within a week, and the larvae feed during July to September for 5 to 6 weeks. The pupae overwinter in the soil. The orangestriped and spiny oakworms
have only one generation per year, while the pinkstriped oakworm has two generations.
Control. - Natural enemies generally prevent widespread defoliation. Chemical control may be needed for high value trees.
Orangestriped oakworm larva. (Click for detail. JPG 38K).
Pinkstriped oakworm larva. (Click for detail. JPG 50K).
Spiny oakworm larva. (Click for detail. JPG 39K).