Efficacy of tebufenozide applied by aircraft using only upwind atomizers to control spruce budworm (Lepidoptera: Tortricidae)

Abstract The efficacy of an aerial spray technique that used only two atomizers on the upwind wing to reduce drift was evaluated by comparing it with a conventional spray application that used two atomizers on each wing. The techniques were field tested in 1995 using double applications of tebufenozide at 70 g in 2 L ha −1 to suppress populations of spruce budworm Choristoneura fumiferana (Clem.) on balsam fir, Abies balsamea . The ‘upwind only’ technique emitted 35–69% of the flow rates (L min −1 ) and dosages (g AI ha −1 ) prescribed for and achieved by the conventional spray techniques. Nevertheless, spray deposit (drops cm −2 ) on kromekote cards did not differ significantly between the two application methods; but significantly more ( P P > 0.05) between the spray treatments but both were significantly better ( P