Fall webworm

Insect

Fall webworm

Hyphantria cunea (Drury)

Lepidoptera: Arctiidae

Distribution: Most fruit-growing states and provinces in eastern North America.

Photos

Damaged fruit. NY State Ag Experiment Station
D

Adult is a white moth with dark spots on the wings, which may be less distinct in northern specimens (A). The pale yellow larva has a dark head and dark tubercles with clumps of hairs (B).

Crops Affected: apples, cherries, peaches, pears, plums

Damage

Attacks all deciduous fruit trees. Larvae feed gregariously within loosely woven dirty white webs that enclose the foliage on the ends of the branches (C). Within the feeding area, leaves are stripped and fruit is damaged (D). Foliar loss is more important on young trees.

Management

This insect causes little damage in orchards receiving a seasonal insecticide spray program and tolerance is more economical than intervention. When necessary, removal of webs and larvae or, if out of reach, use of selective (e.g., Bacillus thuringiensis) or broad-spectrum insecticides is also effective.

Similar Species

Infestations can be differentiated from those of eastern tent caterpillar (Malacosoma americanum) by timing (midsummer and later, rather than spring) and location of webbing (outer regions of branches, rather than in the central crotches).