Eastern Spruce Gall Adelgid on White Spruce

Adelgids overwinter as nymphs on twigs near the terminal buds. They mature around early May and lay their eggs, which hatch in about a week. The young insects then begin to feed on the buds that had been fed on by the overwintering nymphs previously. This feeding induces abnormal growth of plant cells and the progressive enlargement at the bases of infected needles. Eventually, the enlarging needles coalesce and form a characteristic pineapple-shaped gall within which the insect lives and grows. The galls split and the mature adelgids emerge, develop wings, fly to the needles of the same or some other spruce where lay eggs at the base of the new growth. The eggs soon hatch and the immature forms that emerge will feed until the onset of cold weather, overwinter at the needle bases and then resume their life cycle the following spring.

Oddly, only females of this adelgid are known to occur.