Yellowheaded Spruce Sawfly
Pikonema alaskensis |
| USDA Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State Priv. For., For. Insect and Disease Management., Broomall, PA. p. 123, illus. |
The yellowheaded spruce sawfly attacks new foliage of white, black, blue, red, Engelmann, Norway, and Sitka spruces. This sawfly is only found in the northern tier of states. Successive complete defoliations cause mortality, especially of roadside, ornamental, or young plantation trees. Stands with closed crowns are not attacked.
Pupation occurs in the spring, and adults emerge about when the bud scales fall from expanding buds. Eggs are deposited singly in the base of new needles. Larvae are present from late May to mid-July. Mature larvae are olive green above and lighter green below, with several darker stripes of variable width along the back and sides. The head is yellowish-brown and may have brown spots. When mature, the larvae migrate from the trees to the ground to hibernate in cocoons spun in the soil. There is one generation per year.
Larva(e)
E. Bradford Walker, Vermont Department of Forests, Parks and Recreation |
Damage; defoliation
Minnesota Department of Natural Resources Archives, Minnesota Department of Natural Resources |
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