The brown-tail is a moth of the family Lymantriidae. It is distributed throughout Europe. It is found in North America only on the coast of Maine and Cape Cod where it is considered an invasive species that arrived in the U.S. in the 1890s on nursery stock coming from Europe. This univoltine defoliator feeds on 26 genera of non-resinous trees and shrubs belonging to 13 different families. Considering that it is unusual for an insect to feed on members belonging to more than two different families, the polyphagy of this pest is remarkable. Browntail moth polyphagy, together with its tendency to reach outbreak densities, makes this species a major pest of hardwood forests; it may also attack fruit and ornamental trees.