Eastern Tent Caterpillar

These caterpillars produce grayish-white webbed nests on a number of trees in early spring. They hatched from a cluster of eggs laid on trees the previous year. These black shiny swellings encircle the twigs and contain about 150 to 300 eggs. After hatching the caterpillars or larvae quickly gather at a major fork or crotch and begin to build a web. As they go about feeding on newly opened leaves, they spin a fine strand of silk wherever they go. As the caterpillars grow, so does the size of the web. After 6 weeks of feeding the caterpillars become fully grown reaching 1 1/2 to 2 inches in length. At this time they leave their nests in search of places to spin their white cocoons. After pupating reddish brown adult moths emerge. There is one generation per year.

Control: Feeding is seldom life-threatening to the tree. Bacillus thuringiensis (B. t.) is a biological control that is effective on small caterpillars; however, it may be difficult to apply to large trees. Other insecticides are available.