Spruce Budworm Parasite Studies in Northwestern Ontario

Abstract

The extensive coniferous stands in northwestern Ontario have been subjected to repeated widespread outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.) (5). About 1939 two such outbreaks originated almost simultaneously, one on the west shores of Lake Nipigon and the other south of Lac Seul approximately 180 miles farther west. Each outbreak eventually covered thousands of square miles and was responsible for the destruction of hundreds of square miles of balsam fir forest. Studies of the parasite complex attacking the spruce budworm in northwestern Ontario and the assessment of its general influence on budworm population trends were initiated in the Lake Nipigon outbreak in 1946 by Professor N. R. Brown, now of the University of New Brunswick, and were further developed by the senior author from 1947 to 1950. Similar investigations were initiated by the junior author in the Lac Seul outbreak in 1950 and continued until 1954. Studies in both areas were continued on a limited basis until 1956 through the co-operation of several research officers.