Spongy moth (Lymantria dispar) [formerly known as “gypsy moth”] caterpillars can eat leaves from most trees and shrubs in North America. It does, however, prefer some species to others and there are a few trees it won’t touch even when starving. Remember that spongy moth caterpillars feed in May and June. If you notice trees being defoliated at other times of the year it is likely something else that is feeding on them.

Feeding preferences of spongy moth caterpillars on Wisconsin host plants

Favorite foods	Acceptable meals	Won’t touch
oak aspen willow apple and crabapple tamarack white birch witch hazel mountain ash basswood linden pine (older caterpillars) spruce (older caterpillars)	maple walnut chestnut hickory cherry hemlock elm hackberry black and yellow birch beech cottonwood box elder ironwood	green, white, and black ash balsam fir locust scotch pine red cedar tulip poplar catalpa sycamore dogwood