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Home > Bugs > Bugs of Trees and Shrubs > White Pine Weevil

White Pine Weevil—Pissodes strobi

The white pine weevil, which kills the top of conifers, is the most serious economic insect pest of white pine. One of the first symptoms of attack in the spring is the presence of pitch flowing from the feeding punctures in the previous year's leading shoot. Beginning in late June the new growth on infested shoots starts to droop. Shortly thereafter the tops die and turn brown. Up to 2-3 years of top growth may be destroyed. The damage results in trees that are multi-topped, crooked, and of much lower value for sawtimber. Plantations, open-grown trees, and ornamentals are most heavily affected. It attacks eastern white pine, Colorado blue spruce, Norway spruce, jack pine, Scotch pine, mugo pine, and native spruces.

terminal damage caused by white pine weevil close-up of white pine weevil oviposition site adult white pine weevil white pine weevil larva
The larvae do the most damage by killing leaders of infested trees. Leaders with expanding buds droop, forming the typical "Shepard's hook." In spring, the adult females climb to the leaders of trees and feed through small holes chewed in the bark. This feeding causes sap to run down the leader. She will insert eggs into these holes. The adult weevils are light reddish-brown with several patches of white on the wing covers. Like most weevils the adults have a long snout-like beak from which arise knobbed antennae. The larvae, which are found under the bark of the dying leader, are white, legless, C-shaped and have brown heads.

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[Photos, left to right: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Bugwood.org; Rayanne Lehman, Pennsylvania Department of Agriculture, Bugwood.org; Dave Powell, USDA Forest Service, Bugwood.org; Joseph O'Brien, USDA Forest Service, Bugwood.org]

 
It is the policy of the State of Maine to minimize reliance on pesticides. The Maine Department of Agriculture and the Maine IPM Council encourage everyone to practice integrated pest management and to use pesticides only as a last resort. The mention of pesticides in the fact sheets linked to these pages does not imply an endorsement of any product. Be sure that any product used is currently registered and follow all label directions.