The Pine Webworm, Pococera robustella (Zeller)

The pine webworm, Pococera robustella (Zeller) (known for many years as Tetralopha robustella), is a common defoliator of pines in the eastern United States. Infestations commonly occur on young (1-2 year old) pine seedlings, but larger seedlings and branches of mature pines can also become infested. The conspicuous larval nests of the pine webworm can substantially reduce the aesthetic and commercial value of pines grown as Christmas trees or ornamentals (Wallesz and Benjamin 1960). Although severe defoliation can kill first year pine seedlings (Merkel and Hertel 1976), defoliation in plantations and natural forests rarely results in mortality or significant damage, with impact generally limited to reduced seedling growth on stems less than 0.6 m tall (Hertel and Benjamin 1977; USDA Forest Service 1989).