How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Western tussock moth

Tussock moth eggs are laid in midsummer and do not hatch until the following spring; there is only one generation a year except in Southern California where there are two. Eggs are commonly deposited on branches and twigs in an egg sac, usually on an empty tussock moth pupal case. The pupal cases, which are easier to find than the eggs themselves, are light brown, quite hairy, and about 0.5 inch long. Look for them in the dormant season on leafless trees. Eggs hatch when trees leaf out, causing damage in spring. When they arefull grown, larvae spin their distinctive cocoon.

Adults emerge between late spring and midsummer. Adult males are winged; females are wingless and lay a single egg mass.

Tussock moth eggs
Tussock moth eggs
Young larvae
Young larvae
Larvae
Larvae
Pupal case
Pupal case
Adult female
Adult female

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/GARDEN/FRUIT/PESTS/LIFECYCLE/lcwesttussmth.html revised: April 25, 2014. Contact webmaster.