U.S. Department of Agriculture, Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State and Private Forestry, Forest Insect and Disease Management., Broomall, PA. p. 123, illus.(USDA Forest Service, Northeast Area State and Private Forestry Publication. NA-FR-4)
The palmerworm is occasionally responsible for widespread defoliation of hardwoods such as red, white, and chestnut oaks, basswood, cherry, and apple. The larvae skeletonize leaves and may fold or roll them during feeding. Outbreaks rarely last most than 1 or 2 years, and usually occur during unusually hot, dry springs. Although they may cause noticeable defoliation, outbreaks rarely result in permanent tree damage.
Adult moths overwinter and in spring the females lay eggs, depositing them singly on the expanding leaves. Larval feeding peaks during June; the full-grown larvae are about ½ inch long and can be identified most easily by the one narrow and two wide green stripes running down the back. Pupation takes place early in July at the final feeding site, and most adults appear by the end of July. The grayish to brownish adult moths are about 2/3 inch long, and are most conspicuous during outbreaks when large numbers are disturbed from resting sites on shrubs and small trees. There is one generation annually.
