Canadian Forest Service Publications
Deposition of azadirachtin following ultra-low volume aerial applications to red pine plantations for control of pine false webworm, Acantholyda erythrocephala (L.) (Hymenoptera: Pamphiliidae), in Ontario, Canada. 2003. Thompson, D.G.; Mickle, R.E.; Lyons, D.B.; Helson, B.V.; Robinson, A.G.; Chartrand, D.T.; Buscarini, T.M. International Journal of Pest Management 49: 9-15.
Issued by: Great Lakes Forestry Centre
Catalog ID: 23866
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A completely randomized experimental design was employed to assess differences in on-target deposition of azadirachtin A following aerial applications of Fortune AZA 3% (50 g a.i. /ha) to three red pine plantations infested with pine false webworm (Acantholyda erythrocephala (L.)). Substantial differences in mean foliar deposits were observed among plantations. However, these differences were not statistically significant owing to high variability in deposits within spray blocks. All mean deposits were well in excess of levels generating 91% mortality in laboratory bioassays against pine false webworm. In relation to a second objective, poor and occasionally insignificant correlation between deposits on natural foliage and two types of artificial collectors indicated that neither collector was effective in estimating true foliar deposition. Our results suggest that aerial applications of undiluted azadirachtin formulations at nominal rates of 50 g a.i. ham1 yield foliar deposits in red pine canopies sufficient to induce high mortality in pine false webworm populations. Strict control over application parameters (track spacing, upwind offset and flight-line orientation) is necessary to minimize deposit variation.