Larval Densities, Mortality, and Sampling at Different Canopy Levels During a Western Spruce Budworm (Lepidoptera: Tortricidae) Suppression Project

Abstract

Larval densities were not generally different between crown levels of large Douglas-fir trees, but were significantly different between crown levels in white fir. Densitieson seedlings were significantly less than on large trees for both tree species. Mortality attributedto the treatment was relatively uniform between crown levels of large trees and between large trees and saplings, but was less on white fir seedlings, perhaps because thelarge trees sheltered them. The significance of the variation in larval counts associated with plots, trees within plots, crown levels, and branches within crown levels are discussed inrelation to sampling design.