Effect of two commercial formulations of Bacillus thuringiensis subsp. kurstaki on the forest earthworm Dendrobaena octaedra
Authors: Addison, J.A., Holmes, S.B.
Journal, Volume, Year: Canadian Journal of Forest Research, volume 26:1594-1601, 1996
Simple soil-litter microcosms were used to determine the effects of Dipel�8L and Dipel�8AF (Btk) on survival, growth and reproduction of the forest earthworm (Dendrobaena octaedra) over a 10-week period. Survival, growth, and cocoon production were significantly reduced at 1,000X the expected environmental concentration (EEC) of Dipel�8L. However, no adverse effects were found when D. octaedra were exposed to an unformulated preparation of Btk of Dipel�8AF at doses as high as 1,000X EEC. The toxic component of Dipel�8L was found to be the oil-based formulation blank.
One of few studies that has examined sublethal effects (i.e., earthworm reproduction). This study suggests that different formulations can be toxic to forest earthworms (e.g., aqueous vs. oil based formulations). This paper did not use Bt from transgenic plants