Brown-tail larvae have been reported as feeding on 26 genera of non-resinous trees and shrubs belonging to 13 different families. This polyphagy is considered unusual. Non-specific host plant feeding combined with its tendency to reach extreme outbreak densities makes this species a major pest of fruit orchards, ornamental trees and hardwood forests.[13] Partial list of plant species: apple, cherry, beach plum (Cape Cod, Massachusetts), beech, elm, grape, hops, maple, oak, pear, raspberry, rose and willow. An early description of the introduction to the United States in the 1890s identified pear and apple trees as most greatly afflicted, but mentioned that once trees were entirely bare of leaves, the larvae would descend to the ground in great numbers and move toward any leafy plant, including vegetable plants.[1]