Every year, large amounts of transgenic Bacillus thuringiensis (Bt) corn plant residues left in the field are normally incorporated into the soil after harvest. This poses the potential hazard to decomposing soil organisms that might be affected by the Cry1Ab toxin when ingesting the transgenic Bt corn material. In an 8-month field study, during fall, winter and spring, we investigated the degradation of transgenic Bt corn tissue. We used litterbags (filled either with Bt corn or the isogenic control) of different mesh sizes to exclude different groups of soil organisms. The litterbags were buried into the soil of a corn field near Bern, Switzerland, in October 1999. In monthly intervals, we removed a subsample of 42 to 48 litterbags. The dissipation of the Cry1Ab toxin in transgenic Bt corn leaves was quantified using enzyme-linked immunosorbent assay (ELISA). Bioassays with Ostrinia nubilalis (Hübner) were conducted to confirm the insecticidal active form of the Cry1Ab toxin. Furthermore, we investigated the diversity of soil organisms in the litterbags to see whether there are differences in species composition between the Bt- and the control-treatment. In addition, we compared the decomposition efficiency of the different groups of soil organisms in the Bt- and control-treatment.
Species 1: Lepidoptera Pyralidae Ostrinia nubilalis (European corn borer)
Species 2: Poales Poaceae Zea mays (corn)
Keywords: transgenic B. thuringiensis corn, soil
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA