Damage Only the tips of spruce branches are damaged. In Douglasfir, some tip destruction may occur but no gall forms. Spruce trees are usually not killed by this pest, but repeated infestation does weaken them and mar their appearance. Control Don't plant spruce and Douglasfir together. Prune off galls before they open in the summer, and before they turn brown.
Insecticidal soap is an alternative that often provides good control.
Eastern Spruce Gall Adegid Host Spruce Trees Norway, white , red, black, Engelmann, and Colorado blue spruce . This adelgid causes pineapple-shaped galls at the base of twigs, not the ends. These galls are smaller than Cooley spruce galls. Usually the end of the twig is killed by the gall, making the gall and twig look like a long-necked bottle. They are initially green to purplish and, like Cooley spruce gall adelgid, turn brown as they mature.