Comparison of Western Spruce Budworm Populations and Damage on Grand Fir and Douglas-Fir Trees

摘要

Western spruce budworm populations and damage on grand fir and Douglas-fir were compared. Grand fir showed more damage than Douglas-fir in a given period of time. Egg populations on the two species were similar in the upper crown third, but higher on Douglas-fir in the middle and lower crown thirds. Larval density was similar.