Field studies were conducted in 1992 and 1993 in Hermiston, Oregon to evaluate non-target impacts of transgenic Bt potato (Newleaf®, which expresses insecticidal protein Cry3Aa) and conventional insecticides for control of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say). Pitfall traps were used to estimate the abundance of non-target ground-dwelling arthropods in both Bt and non-Bt potato fields treated with different CPB control regimes. There were no significant differences in the abundance of dominant ground-dwelling Coleopteran predators (carabids and staphylinids) among Bt and non-Bt potato fields treated with weekly sprays of microbial Bt-based formulation containing Cry3Aa, bi-weekly applications of permethrin, early- and mid-season in-furrow applications of systemic insecticides (phorate and disulfoton) or no insecticides. While weekly sprays of permethrin significantly reduced abundance of ground-dwelling spiders (Araneae), there were no significant differences in the abundance of these spider populations between Bt and non-Bt potato fields treated with Bt sprays, systemic insecticides or no insecticides. Significantly more springtails (Collembola: Entomobryidae and Hypogastruridae) were captured in potato fields treated with permethrin than any other CPB control regimes (transgenic Bt potato alone, microbial Cry3Aa formulations, applications of systemic insects, or no control measures), among which there were no significant differences in abundance of the springtail populations. We conclude that the use of transgenic Bt potatoes expressing the insecticidal protein Cry3Aa for control of CPB has no deleterious effects on populations of non-target ground-dwelling arthropods, and thus offer advantage over broad-spectrum insecticides for development of ecologically-sound potato IPM programs.
Species 1: Coleoptera Chrysomelidae Leptinotarsa decemlineata (Colorado potato beetle)
Species 2: Bacillales Bacillaceae Bacillus thuringiensis (Bt)
Keywords: Transgenic crops, Non-Target Effects
Back to Ten-Minute Papers, Subsection Ca. Biological Control
Back to Ten-Minute Papers, Section Ca, Cb, Cc, Cd, Ce, and Cf
Back to The 2002 ESA Annual Meeting and Exhibition