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A faunistic approach to assess potential side-effects of genetically modified Bt -Corn on non-target arthropods under field conditions

2004; Taylor & Francis; Volume: 14; Issue: 2 Linguagem: Inglês

10.1080/09583150310001655701

1360-0478

M. P. Candolfi, Keith Brown, Christoph Grimm, B. Reber, Heinz Schmidli,

Genetically Modified Organisms Research

Abstract A faunistic study investigating the potential side-effects of corn (Zea mays) genetically modified to express a truncated Cry1Ab protein derived from Bacillus thuringiensis subsp. kurstaki, on non-target arthropods was carried out under field conditions. The communities of non-target arthropods in the soil, on the leaves and flying in the crop area were monitored throughout the growing season. Water-treated, untransformed corn served as a control, and a spray application of a bacterial Bt insecticide (Delfin WG) and a synthetic insecticide (Karate Xpress) used to control the European corn borer (Ostrinia nubilalis; Lepidoptera: Pyralidae) acted as positive reference treatments. Results were analyzed using a principal response curve. Significantly lower infestations by the lepidopteran target species O. nubilalis were observed in the Bt-corn plots compared to the control. No effects of Bt-corn on the communities of soil dwelling and non-target plant dwelling arthropods were observed. A trend towards a community effect on flying arthropods was observed with lower abundance of adult Lepidoptera, flies in the families Lonchopteridae, Mycetophilidae and Syrphidae, and the hymenopteran parasitoids Ceraphronidae. Effects were weak and restricted to two sampling dates corresponding to anthesis. A short but statistically significant effect of Karate Xpress and Delfin was observed on the community of plant dwellers and a prolonged effect of Karate Xpress on the soil dwellers. Keywords: non-target arthropodsfaunaside-effectsBt-corntransgenic plantsBacillus thuringiensisCry1AbpesticidesDelfinKarate Xpresslambda-cyhalothrinbiosafety Notes IOBC: International Organisation for Biological and integrated Control of noxious animals and plants ESCORT: European Standard Characteristics of nOn-target arthropod Regulatory Testing SETAC: Society of Environmental Toxicology and Chemistry – Europe BART: Beneficial Arthropod Regulatory Testing Group EPPO: European and Mediterranean Plant Protection Organisation Due to flooding of some pitfall traps, fewer samples were available for the 9 July 1998 sampling date (20 instead of 30 for the control, 21 instead of 30 for the Bt-corn, 16 instead of 20 for the Delfin and 15 instead of 20 for the Karate Xpress treatment). Due to a very high abundance of taxa and individuals, it was decided to identify the arthropods from only 5 out of 10 traps. One trap in the Delfin treatment was lost on one sampling interval (5th sampling). To make the abundance counts comparable, the abundance of the first two beating samples – carried out on 50 plants as compared to 100 plants in later samples - were multiplied by a factor 2.