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Stark-Billings County |
Extension Spotlites
June 12, 2008
Tent Caterpillars
Three species of tent caterpillar occur in North Dakota: eastern tent caterpillar, forest tent caterpillar, and prairie tent caterpillar. Host plant damage by these moth species is caused by the larvae, or "caterpillars."
Eastern ten caterpillar prefers chokecherry, though occasionally it will use other hardwood species. Larvae of eastern ten caterpillar are gregarious and construct tent-like nests of silk in the forks of branches and smaller trees.
Larvae are black and rather hairy, with a whitish-yellow stripe down the middle of the back, narrow broken orange stripes just to either side of the whitish mid-stripe, and lateral white and blue markings.
Adult moths appear in late June and early July. Females lay eggs in a bank-like cluster around small twigs. Eggs overwinter and larvae emerge in the spring; thus, there is one generation per year.
Forest tent caterpillar utilizes a wide variety of hosts, including ash, aspen, basswood, birch, cottonwood, elm, maple, and oak. Larvae emerge in the spring from overwintered eggs. Emergence coincides with the flush of host plant foliage. Larvae are identified by keyhole-shaped spots along the midline of the back and by broad bluish lateral bands. Unlike other tent caterpillars, forest tent caterpillar does not form a tent. Instead, larvae gather and spin silken mats on branches. Adult moths emerge about 10 days after cocoons are spun. Females deposit eggs around small twigs.
Prairie tent caterpillar can utilize a variety of hardwood host, though chokecherry is its preferred host. Prairie tent caterpillar is the most common tent caterpillar species in North Dakota. Prairie tent caterpillar overwinters in the egg stage and larvae emerge in the spring with the flush of their host plant foliage. Larvae are black with a white mid-line stripe broken into dashes and light blue lateral stripes also broken into dashes. Like eastern tent caterpillar, larvae of prairie tent caterpillar form silken tents in the forks of branches and small trees and feed on nearby foliage. Adult moths emerge in mid-summer. Females lay eggs near the base of the host plant in the ground.
Damage by larval feeding of all species does not result in permanent damage unless feeding is severe.
Control of all tent caterpillar species should target larvae. Actively feeding larvae are easily controlled with conventional foliar insecticides including acephate, carbaryl, imidacloprid, or any of several pyrethroids. Biorational treatments include Bacillus thuringiensis (Bt), insecticidal soap, and pyrethrin. Tents also may be physically removed and destroyed.
For more information contact:
Kurt Froelich,
Extension Agent
NDSU Extension Service
Stark-Billings County
1340 W. Villard St.
Dickinson ND 58601-4646
(701) 456-7665