COMPARATIVE EFFICACY OF THURICIDE 16B® AND DIPEL 88® AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE) IN BALSAM FIR STANDS

Abstract

AbstractThe effectiveness of Thuricide 16B®, a water-based commercial formulation of Bacillus thuringiensis var. torstaki (B.t.), Dipel 88®, an oil-based formulation, and the Dipel® vehicle (Dipel 88 without B.t.) were compared by aerial applications against the spruce budworm, Choristoneura fumiferana (Clem.) in balsam fir, Abies balsamea (L.) stands. The two B.t. products applied at similar dosage rates were similar in effectiveness and the Dipel vehicle was not toxic for budworm larvae at rates applied Comparisons of populations of parasites made between pre- and post-spray sampling periods and between treated and untreated plots indicated no direct effect of Dipel 88 on the rate of larval and pupal parasitism.