Tussock Moth Egg Mass

Commonly found on the bark of many deciduous trees, backyard structures, and building walls throughout North America.

Eggs do not eat, but once hatched, larvae feed on the foliage of over 140 species of trees and shrubs, including maple, oak, and birch.

Eggs are laid in late summer or fall in a frothy white mass that hardens into a protective crust. They overwinter in this state and hatch in late spring.

The larvae (caterpillars) are major defoliators of forest and urban trees. Contact with the hairs of the caterpillars (not the eggs) can cause skin irritation or 'urticaria' in humans.