Death and Deterioration of Balsam Fir Weakened by Spruce Budworm Defoliation in Ontario: Part I Notes on the seasonal history and habits of insects breeding in severely weakened and dead trees

Abstract

One of the problems arising from severe outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), is the evaluation of the factors contributing to the decline of the host trees. An intensive study of the death and deterioration of balsam fir, Abies balsamea (L.) Mill., was carried out from 1946 to 1951 in the area southwest of Lake Nipigon in northwestern Ontario, where a severe spruce budworm outbreak was in progress.