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 primarily from into July. 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||Unlikely to be fed on|
apple and crabapple
pine (older caterpillars)
spruce (older caterpillars)
black and yellow birch
green, white, and black ash
In addition, many reports from the Midwest have indicated that blue spruce can sometimes serve as a good habitat for spongy moth caterpillars. The dense canopies and sharp needles can protect spongy moth caterpillars from predators and other natural enemies.