A Cartographic History of Spruce Budworm Outbreaks and Aerial Forest Spraying in the Atlantic Region of North America, 1949–1959

Abstract

The spruce budworm (Choristoneura fumiferana (Clem.)) is a forest pest in all Canadian Provinces and Territories, and in the northeastern, midwest, and northwestern Unired States. It is by iar the most destructive insect affeiting the extensive balsam fir-spruce forest types in Ontario, Quebec, the Maritime Provinces, and Maine. Outbreaks of varying extent have been reported from these regions almost every year for the past half-century (deGryse, 1947). Periods in which outbreaks were particularly severe and widespread occurred from about 1909 to 1920 and in the 1940's and 1950's. In both periods, outbreaks showed a tendency to shift from west to east, intensifying first in parts of northern Ontario and Quebec and dying out in the Atlantic region south of the St. Lawrence River.