Orangestriped Oakworm

Orangestriped Oakworm
Anisota senatoria (J.E. Smith) (Saturniidae)

L.L Hyche, Associate Professor
Department of Entomology & Plant Pathology
Auburn University

The orangestriped oakworm (Photo 1) occurs throughout most of the East from southern Canada south to central Alabama west into Texas and Minnesota. It is reportedly more common in the northern parts of its range than in the South. Oaks are the primary hosts, but the caterpillar has been reported to feed also on maple, hickory, and birch.


Life Cycle, Description, and Habits

The insect overwinters as a pupa (Photo 2) in the soil; moths emerge in mid-summer. Adults are reddish brown, and similar to spiny oakworm moths (see spiny oakworm). Females deposit eggs in clusters on the lower surfaces of leaves. Larvae tend to feed in groups, defoliating one branch then moving to another. The full-grown caterpillar (Photo 1) is 40-50 mm long, and black with eight orange to yellow longitudinal lines down the back and sides of the body. There is a pair of long, slender, black spines on the second segment of the thorax and sets of shorter sharp, black spines along the body rearward. When fully grown, caterpillars leave tree foliage and enter the soil to pupate. Only one generation occurs each year in Alabama.

Occurrence, Damage, Importance 

The orangestriped oakworm is reported to be a serious defoliator of trees in the northern areas of its range. In Alabama, it has been encountered occasionally on water and red oaks, and has been collected in Lee County, which is about the southern edge of its natural range. Caterpillars are normally found in late August, September, and early October. Damage has been primarily aesthetic, and in this area, the species appears to be important mainly as a pest of urban forest trees.