- Ford, Robert P.
USDA Forest Service
The spruce budworm (Choristoneura fumiferana (Clemens)) is a native of the Lake States (Michigan, Wisconsin, and Minesota) where it is a major pest of the balsam fir (Abies balsamera (L.) Mill) and white spruce (Picea glauca (Moench) voss). Budworm attacks it's host in midsummer when the moths lay masses of about 25 eggs on the needles. The eggs hatch in about 10 days. The first instar larvae disperse within and between trees, then hibernate on the host. In the spring, the larvae emerge, mine a needle or two, then bore into buds. As the buds flush, the budworm larvae becomes a free feeder on expanding needles. Larvae pupate and become moths in late July.