Biology and management of the fall webworm, Hyphantria cunea (Lepidoptera: Erebidae)

Abstract

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Erebidae), is a widespread defoliator that is native throughout the continental United States, as well as southern Canada and northern Mexico. It has been introduced accidentally into many parts of Europe and Asia. Larvae have been recorded from > 400 species of forest and shade trees, primarily hardwoods, but also several conifer species in the southern United States. This species is of minor importance in forests, but can cause serious losses in pecan and fruit tree orchards and is a major nuisance in urban parks and homelots where it often completely defoliates ornamental and shade trees. Fall webworm larvae construct conspicuous webs that start at the ends of branches and expand as the larvae grow to incorporate multiple branches. Foliage within webs is completely consumed. Two color races occur throughout the range of this moth, but pure white adults and black-headed larvae predominate in northern regions, whereas spotted adults and red-headed larvae predominate in southern regions. Populations of fall webworm are regulated naturally in its native range by host quality and abundance and by at least 50 species of dipteran and hymenopteran parasitoids and 36 species of predators and parasites. Physical removal, biocontrol, and insecticides are available for management of this moth.