Effects of harvest treatments on spruce budworm, Choristoneura fumiferana (Clem.) (lepidoptera: Tortricidae), dispersal within forest stands

Abstract

Dispersal is a critical trait during the life history of the spruce budworm, Choristoneura fumiferana (Clem.), which leads to its widespread infestation and damage. Budworm dispersal study is of importance for protecting and regenerating valuable white spruce, preferred by the forest industry. One factor that influences dispersal is forest density. The objectives of this project were to investigate: 1. the effects of harvest treatments on the larval dispersal of spruce budworm; 2. the effects of harvest treatments on the responses of budworm male moths to pheromone traps. Harvest treatments were set up in two plots near Black Sturgeon Lake in the late fall of 1993 as follows: one uncut treatment, one partial cut with white and black spruce left, one partial cut with white spruce and birch and aspen left, and one strip clearcut. Spruce budworm egg-mass and larval densities were determined by branch sampling. Sticky traps were deployed for small larval dispersal, water traps for large larval dispersal, and pheromone traps for the responses of male moths to them in the above treatments during 1994 and 1995.