Needles on the ends of branches are chewed and webbed together. Brownish caterpillars up to 1 inch long with yellow raised spots are feeding on the needles. Initial damage occurs on new foliage, often near the top of the tree. The whole tree may be defoliated. By midsummer, branch ends may turn reddish brown, becoming gray in the fall. Branches or the entire tree may die after 5 or more years of defoliation.
Apply an insecticide labeled for this pest, following label directions.