Adelgids are a small group of insects that are closely related to aphids.
In Saskatchewan and Manitoba where there is no native Douglas fir, the adelgid has the capability of completing its life cycle entirely on spruce. Only the first form of adelgid causes a formation of galls, whereas, the remaining forms feed openly on needles. Another form of the cooley spruce gall adelgids produce white, cottony protective covers for their eggs. These cottony covers appear as white specks early in the spring and continue throughout the summer, and can cover an entire tree during a severe infestation. Damage first occurs in late May when the new growth of the branch tips form into cone-shaped galls.