The fall webworm, Hyphantria cunea
, is a moth in the family Arctiidae known principally for its larval stage, which creates characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. The adult is a white or white and black spotted moth with wing span 30mm. Females lay between 300-1000 eggs in batches of about 100; the larvae hatch out and feed together from a inside their web structure, which they build and continually enlarge as they grow. In North America, where it is native, many natural enemies help maintain low-level populations and although their numbers do periodically crest into outbreaks, the fall webworm is mainly an aesthetic pest usually without economic consequence. Healthy trees, although they can become defoliated sometimes two years in a row in outbreaks, usually recover. The fall webworm is among the most polyphagous of insects, feeding on just about any type of deciduous tree. Worldwide, it has been recorded from 636 species. When it entered Europe in the 1940s there was great concern for containing its rapid spread. Currently it is well established across Europe and Asia, and although it is a significant pest of hardwoods orchard and ornamental trees in some Eastern European regions, it is now fully established across these continents, and is considered a static pest responsible for local damage.
Much research energy has been put into biological control of the fall web worm using Bacillus thuringiensis kurstaki
, which has been especially effective in containing populations in Korea and Hungary. Sex pheromones have been obtained from female H. cunea
and are used in monitoring traps.
; Global Invasive Species Database 2007; Hyche 1999