Forest Health Protection, Southern Region

Importance. - The poplar tentmaker occurs in southern Canada and from New England to Georgia and Colorado. Endemic populations may defoliate small groups of poplar and willow, especially trees growing in the open. Epidemic populations may completely defoliate large cottonwood plantations. Complete defoliation twice during the same growing season will result in growth loss, crown dieback, and in some cases, tree mortality.

Identifying the Insect. - Full grown larvae are light brown to nearly black and Up to 1 3/ 15 inches (42 mm) long. They have four light yellow lines on the back, and a bright yellow and several indistinct lines on each side. Adults are brownish gray, with three whitish lines crossing each forewing. The hindwings are crossed by a wavy band.

Identifying the Injury. - Newly hatched larvae skeletonize the leaf; older larvae devour all except the leaf stalk. Severe defoliation occurs during summer and early fall. Many one or two-leaf webbed tents hang from the branches.

Biology. - Moths appear from March through September and lay cream to pink colored eggs in clusters of 150 to 300 on the leaves. The larvae are gregarious and live in tents or webs constructed by pulling together the edges of one or more leaves and lining them with silk. They feed from May to October and pupate in loose cocoons. There are four generations per year in the South.

Control. - Natural controls include parasites of the pest's eggs and larvae. Predators and virus and fungus diseases also kill the poplar tentmaker. Two chemical insecticides are registered for control.