The pine shoot moth was first observed in the U.S. in 1913, attacking ornamental Scotch pine on Long Island. Beginning in 1925, this species of moth spread rapidly throughout southern New England.
Identification and Life Cycle
Moths fly over an extended period from mid-July through September, laying eggs that hatch within 7 to 10 days. The larvae bore into needle sheaths, feed, and then bore into the buds. The larvae overwinter within the buds or under resin masses, attacking uninfested buds or expanding shoots in the spring.
Description of Damage
Buds or shoots with large pitch globules are evidence of attack. Distorted or dying shoots are often evident if moths are abundant. Injury may occur as bushy growth on leaders or ends of lateral branches, forking of the leader, tree-stunting or the presence of dead, curled shoots.
Clip off infested shoots in May and July. Be sure to destroy the clippings from May because the larvae can complete the life cycle inside them. An insecticide spray such as Borer-Miner Killer by Bonide can be effective, but only if applied at the correct time. The larvae are first needle miners and then shoot borers and it is necessary to catch them as they move. Spray when they first emerge from the buds in early to mid-May, then spray again in late July as the larvae move from the mined needles to buds.