The Spongy Moth is a foreign pest with few native predators to keep populations in check. Caterpillars feed on tree leaves, preferring those of oak, aspen, poplar, and birch. When those are not available, other tree species and evergreens are also at risk. Large populations can defoliate entire wooded areas. Caterpillars in large numbers and their waste (frass) are a nuisance on residential property. Spongy Moth can not be eradicated, but they can be suppressed to tolerable levels.