E.G. Kettela, V. Steel


Executive Summary

In 1990 a collaborative research project was conducted that involved Forest Protection Limited, Ministère des Ressources naturelles du Québec, the Canadian Forest Service-Maritimes, the Spray Efficacy Research Group and the New Brunswick Research and Productivity Council. The primary goal of this project was to determine the effectiveness of B.t. against high spruce budworm populations and to explore the potential of widening the spray window by spraying earlier in the season. This project, conducted in the St. Paulin area of the Gaspé, called for the treatment of nine sites using a novel line transect spray and assessment technique. In all 5 sites were treated early in the feeding cycle (LD1 3.3), 3 sites late (LD1 - 5.2 to 5.4) and 1 site sprayed twice. A Cessna 188 aircraft equipped with 4, AU 4000 Micronairs was used to apply all sprays. The results indicate that it may be possible to expand the spray window and provide sufficient protection from high level of budworm larvae but that this can be achieved primarily by enhancing spray deposit and taking advantage of any protracted warm spells in the spring. A higher deposited dose will be necessary.