After laying eggs on suitable host plants, adults adelgids die. These eggs hatch and newly emerged nymphs overwinter at the base of dormant buds. Stem mothers on spruce . Pineapple-shaped galls form at the base of new growth as a result of the feeding from larvae. Galls dry to a brown colour in late summer.
Chambers crack open to release winged adults.
Adults and nymphs suck plant juices resulting in the formation of galls. This adelgid can complete its life cycle either on spruce or Douglas fir or live part of its life on spruce and on Douglas fir. Its life cycle is similar to that of the eastern spruce gall adelgid. Immature females, overwintering under bark scales near the dormant terminal buds, are small, grey and oval in shape. As the new growth begins, adults can be easily recognized by the masses of white, waxy, hairy fibres which they produce.