Cooley Gall, Cooley galls are commonly found on the new growth of spruce trees. These galls are produced by Insects called Cooley spruce gall adelgids (woolly aphids). Galls appear early in the season as 2- to 4-inch cucumber-shaped growths. The galls are light green during late spring and early summer but dry out and become brown starting in mid-July. The galls often are mistaken for seed cones.  

Cooley spruce galls are conspicuous and frequently cause considerable concern to homeowners. However, the galls usually do not cause any serious harm to the tree. Extremely heavy infestations may cause minor retardation of tree growth and some distortion. However, in most cases, old galls are covered by new growth the following season and become almost unnoticeable a few years after they form.

FAQ

• Treatments:
  Spraying (Imidacloprid, Permethrin, Bifenthrin, Carbaryl), Basal Trunk Application (Dinotefuran / Safari ®)