Forest Pests: Insects, Diseases & Other Damage Agents

White Pine Weevil
Pissodes strobi (Peck)

Hanson, T., and E. B. Walker. [n.d.] Field guide to common insect pests of urban trees in the Northeast. Waterbury, VT: Department of Forests, Parks and Recreation.

Coleoptera: Curculionidae Hosts: White pine, Norway spruce, other spruce and pine species, Douglas fir Evidence: On sunny days in early spring, look for adults (a) near terminal buds. Pitch flow from feeding and egg-laying punctures is common in the leaders of infested trees (b). Tops may be stunted, drooping or dead by mid-summer (c). Dead terminals sometimes take on the appearance of a shepherd's crook. Two or more whorls can be afffected and occasionally smaller trees may be killed. Life Cycle: Adults overwinter in the duff under infested trees. They emerge in very early spring to begin feeding and egg-laying in last year's terminal shoot. Upon hatching, larvae tunnel downward beneath the bark, girdling the leader (d). Pupation takes place in the oval chip-lined cells beneath the bark in the feeding channel. Adults emerge in July and August and drop to the ground. Management: Flagged terminals should be pruned out below the larval tunnels and destroyed as soon as they are seen. When infestations are heavy, treatment of terminals in early spring with a residual insecticide can eliminate adults as they are feeding, but before they begin ovipositing.
	a. Look for adult white pine weevil near the terminal leader in early spring.
	b. Pitch flow is associated with feeding and egg-laying
	c. Dead terminal caused by white pine weevil
	d. Larvae tunnel down the infested leader, girdling the terminal.

Photo Credits:

Figure a: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Waterbury, VT.

Figure b: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Waterbury, VT.

Figure c: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Waterbury, VT.

Figure d: Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, Morrisville, VT.

References:

Drooz, A.T. 1985. Insects of Eastern Forests. USDA Forest Service Miscellaneous Publication 1426. p 328-329;

Johnson, W.T. and Lyon, H.H. 1991. Insects That Feed on Trees and Shrubs. 2nd edition. Cornell University Press. p 54-55;

Martineau, R. 1984. Insects Harmful to Forest Trees. Agriculture Canada Government Publishing Centre, Supply and Services, Ottawa. p 61-63;

Rose, A.H. and Lindquist, O.H. 1999. Insects of Eastern Pines. Canadian Forest Service Publication 1313. p 25-27.

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