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Entomology: Landscape Pest Management: Insect ID : Ornamentals

Insect Pests of Ornamentals - Fall Webworm

Fall Webworm web

Fall Webworm (Hyphantria cunea)

Adult moths are about 3/4 inch long with wings folded. Wings are all white or white with black spots. Bases of front legs are orange-yellow. Mature larvae are about 1 inch long and may occur in two color forms: those with black heads are yellowish white and those with red heads are brown. Both forms have paired black tubercles running down the back. They are covered with long, silky gray hairs. There are four generations a year. Pupae overwinter in flimsy cocoons in protected places.

Preferred hosts include mulberry, walnut, hickory, elm, sweet gum, poplar, willow, oak, linden, ash, and apple and other fruit trees.

The caterpillars produce a "web" of fine silk over terminals. They feed inside the silken web, which they enlarge to take in more foliage as they grow.

In early spring, examine the south side of tree crowns for the first signs of webbing over terminals. Insecticides must penetrate the" nests" to provide good control.

Fall Webworm caterpillars