Western tent caterpillar
12 host plants
Last updated
Western tent caterpillar larvae construct large, conspicuous white silken tents in the crotches of alders, willows, and fruit trees by late April or May in western Washington. Brownish, hairy larvae feed gregariously inside and around webs. Look for scattered defoliation in the immediate tent vicinity. Complete defoliation of small trees is possible, though recovery occurs rapidly.
Prune and burn tents containing live larvae in late April or early May. Wrapping trunks with burlap and collecting aggregating caterpillars at night provides mechanical suppression on small trees. Do not burn tents in trees, as this causes fire risk. Natural parasitoid populations suppress tent caterpillars the following year; avoid pesticides that eliminate these beneficial insects.
Quick Reference
Cultural Controls
- biological control Infestations of tent caterpillars occur cyclically as populations of the caterpillars and their predators rise and fall.
- Tent caterpillars have many natural enemies.
- Some birds eat the caterpillars, and small mammals consume the pupae.
- The larvae of a tachinid fly parasitizes the caterpillars.
- Management-cultural control Home orchardists: Remove egg masses from twigs or other sites.
- Cut out infested twigs and dip in a bucket of soapy water.