Fall web worms usually appear on trees in late summer or Fall where as Tent caterpillars appear in the Spring.
The fall webworm is a moth in the family Erebidae known principally for its larval stage, which creates the characteristic webbed nests on the tree limbs of a wide variety of hardwoods in the late summer and fall. It is mainly an aesthetic pest and is not believed to harm otherwise healthy trees.
Unlike eastern tent caterpillars, the fall webworm feeds within its tent, which encloses foliage at the end of branches. Defoliation by fall webworm caterpillars does not usually cause damage to the tree, since they feed in late summer or fall, just before leaf drop. Control of fall webworm is usually for aesthetic benefit.
The hairy caterpillars vary in color and come in two forms: red-headed and black-headed. They tend to be pale yellow or green in color, though some may be darker. Each segment of the caterpillar’s body has a pair of spots on the back. At maturity, the larvae may reach one inch in length.
The adult fall webworm moth is bright white, with a hairy body. Like most moths, the fall webworm is nocturnal and attracted to light.
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