Methods are reported for testing the effects of toxins or small molecules [B. thuringiensis var. kurstaki d-endotoxins HD-1 CryIA(b) and HD-73 CryIA(c)] in plants (cotton and potato) on 2 nontarget soil arthropods, a collembolan,  F. candida Willem, and an orbatid mite, O. nitens Koch.  Time to oviposition, egg production, and final body length were unaffected when F. candida were fed residues of 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 three 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.