Pest description and damage Adult moth is dark brown with a wing expanse of 0.5 inch. The larvae are light greenish to brown and grow to approximately 0.5 inch long. The spruce needleminer feeds on spruce needles from the inside out, starting at the base of the needle. Large amounts of webbing are deposited around the needles. Completely mined and hollowed out needles look translucent and may be cut off, sometimes resulting in severe needle loss. The spruce needleminer attacks mainly blue, Sitka, and Engelmann spruce in the western U.S.
Biology and life history The larvae overwinter in hollowed-out needles. As the weather warms, they resume feeding and pupate in mid-spring. Adult moths emerge in May and June and lay eggs on needles. When eggs hatch, each larva cuts a hole near the base of the needle and then mines the interior. There is one generation per year.
Hand-pick larvae on small trees.