Canadian Forest Service Publications

Design and evaluation of an aerial spray trial with true replicates to test the efficacy of Bacillus thuringiensis insecticide in a boreal forest. 2003. Cadogan, B.L.; Scharbach, R.D. Journal of Economic Entomology 96: 388-395.

Year: 2003

Issued by: Great Lakes Forestry Centre

Catalog ID: 21683

Language: English

CFS Availability: PDF (request by e-mail)

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Abstract

A field trial using true replicates was conducted sccessfully in a boreal forest in 1996 to evaluate the efficacy of two aerially applied Bacillus thuringiensis formulations, ABG 6492 and ABG 6430. A complete randomized design with four replicates per treatment was chosen. Twelve to 15 balsam fir (Abies balsamea [L.} Mill.) per plot were randomly selected as sample trees. Interplot buffer zones, > 200 m wide, adequately prevented cross contamination from sprays that were atomized with four rotary atomizers (volume median diamters ranging from 64.6 to 139.4 ┬Ám) and released ~ 30 m above the ground. The B. thuringiensis formulations were not significantly different (P>0.05) from each other in reducing spruce budworm (Choristoneura fumiferana [Clem.]) populations and protecting balsam fir trees from defoliation but both formulations were significantly more efficacious than the controls. The results suggest that true replicates are a feasible alternative to pseudoreplication in experimental forest aerial applications.