The spruce needle miner makes a small hole in the base of a needle then mines out the center. Dead needles are webbed together and can be found on infested twigs. Use Orthene, Sevin, or Diazinon, when the insects are actively feeding, usually late April to early May and again in late July. Pine needle scale is a white, elongated scale. Spray with Diazinon, Orthene, Sevin or malathion when crawlers are present.
Spider mites can be problem in summer after hot dry weather.
The small insects can't be readily seen with the naked eye. The first noticeable symptoms are yellowing of the oldest needles on infested branches. Close inspection with a magnifying glass will confirm the presence of the mites. Use Orthene according to label directions. Sawfly larvae may feed on the needles.