Effects of Bacillus thuringiensis toxins in transgenic cotton and potato on Folsomia candida (Collembola: Isotomidae) and Oppia nitens (Acari: Orbatidae)

Abstract

Methods are reported for testing the effects of toxins or small molecules [Bacillus thuringiensis ssp. kurstaki delta-endotoxins HD-1 CryIA(b) and HD-73 CryIA(c) in plants (cotton and potato) on 2 nontarget soil arthropods, a collembolan, Folsomia candida Willem, and an orbatid mite, Oppia nitens Koch. Time to oviposition, egg production, and final body length were unaffected when F. candida were fed residues in transgenic cotton lines 81 or 249. Total production of O. nitens adults and nymphs was unaffected by feeding on leaves of both transgenic cotton lines. With B. thuringiensis ssp. tenebrionis CryIIIA in potato, no differences were seen in the 3 indices for F. candida. Overall transgenic toxin sources had no negative effects, but similar tests with cadmium as a positive control showed a concentration-rate response of decreased reproduction.