Canadian Forest Service Publications
Bacillus thuringiensis : a most logical weapon for spruce budworm control. 1978. Smirnoff, W.A. Forestry Chronicle 54: 309-312.
Issued by: Laurentian Forestry Centre
Catalog ID: 16412
Availability: PDF (request by e-mail)
Action of Bacillus thuringiensis (B.t.) on spruce budworm, Choristoneura fumiferana Clem., was found to be attribuable to septicemia with some enterotoxicosis. Development of a compact economical B.t. formulation, with addition of the enzyne chitinae, increased its efficiency by accelerating larval mortality. Between 1971 and 1975 field tests were conducted in balsam fir stands with different levels of insect density to select the best formulation and methods of application and to identify the major influencing environmental variables. Variability in the results prior to 1975 is attributable to difficulties with calibration of spray systems. With accurate calibration in 1976 and 1977, good results in terms of larval mortality and foliage protection were obtained, thus confirming the value of B.t. for control of spruce budworm.