Question
Is there a systemic ground application I can use for my spruce trees?  From the pictures it looks like cooley spruce galls.  I have a few trees that are quite large and would be hard for me to spray them.  If I can use a ground application what's the best time of year?

Answer
Cooley spruce galls are common and conspicuous on blue spruce. However, they do little or no harm to the tree.
The galls are produced by aphid-like Insects, Cooley spruce gall adelgids.
Cooley spruce gall adelgids require two hosts to complete their normal life cycle: spruce and Douglas-fir.
Once the galls begin to form, insecticides usually are ineffective because the Insects are protected within the galls.
The best times to spray are in the spring before new growth starts or in the fall when overwintering stages of the insect have returned to the tree.
Soil injections of imidacloprid (Merit) can control Cooley spruce gall adelgids. However, the treatments often fail to kill many of the Insects until after the galls are formed. These galls usually remain green rather than browning in early summer. Fall applications are recommended for this insect.