History of a pine false webworm (Hymenoptera: Pamphiliidae) outbreak in northern New York

A sustained outbreak of pine false webworm, Acantholyda erythrocephala (L.) (Hymenoptera: Pamphiliidae), in northern New York is unprecedented in its extent and duration. White pine, Pinus strobus L., is the preferred host in this region. What began as a 30-ha infestation of this introduced sawfly in 1981 affected 5440 ha of white pine distributed throughout 231 000 ha in St. Lawrence and Franklin counties by 1995. Occurrence of A. erythrocephala in the United States has been documented in eight northeastern and one north-central state (Connecticutt, Massachusetts, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, and Wisconsin) and three Canadian provinces (Alberta, Newfoundland, and Ontario). Possible explanations for the occurrence and tenure of the current outbreak in New York are discussed.