Spruce Gall Aphid

The Spruce Gall Aphid affects the new growth on the ends of the branches each year. The adult female winters on the underside of the branches and will lay her eggs at the base of the new growth. When the eggs hatch, a nymph emerges and feeds on the tender new growth. A chemical in their saliva affects the tree and causes it to form gall tissue that grows around the nymphs. This cone like structure will turn to a purple color. The nymph feed on the tissue until they emerge mid to late summer. This causes the galls and the needles to brown, dry out and harden.