Dendroctonus in late June. Look for white-flecks or brownish foliage. Larvae found in clusters on the foliage. The center pitch of these shoots will be hollow. This a a quarantine pest not presently found here.
Symptoms are dead and dying new shoots with expanded needles.
Several generations per year so additional treatments may be needed in late June and July. Small clusters of discolored needles webbed tightly together and flattened against the branch. Needles are hollowed-out with small holes near the base. Yellowish to rusty-brown needles. To observe mites, shake a branch over a piece of white paper, moving specks are mites.