Canadian Forest Service Publications
An assay of sequential application of Fenitrothion and Bacillus thuringiensis for an integrated control of the spruce budworm. 1978. Smirnoff, W.A.; Hardy, Y. Can. J. For. Res. 8(3): 300-305.
Issued by: Laurentian Forestry Centre
Catalog ID: 16419
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Three 40-ha blocks were sprayed by helicopter in order to assess the possibilities of integrating a biological and a chemical insecticide for the control of spruce budworm (Choristoneura fumiferana (Clem.)) on balsam fir (Abies balsamea (L.) Mill.). One block was sprayed with Fenitrothion alone before completion of emergence of the second instar larvae. A second block was also sprayed with Fenitrothion at the same timing, followed by an application of Bacillus thuringiensis at bud expansion. A third block was treated with B. thuringiensis alone. The highest larval mortality and best foliage protection were obtained in the block treated with B. thuringiensis alone. Unfavorable meteorological conditions prevailing when B. thuringiensis was applied in the block treated with both the chemical and the biological insecticides partially accounted for the less favorable results. Further it seemed probable that the Fenitrothion applied before completion of emergence affected only those larvae that were not mining old needles or buds.