Auchenorrhyncha (planthoppers and leafhoppers) are herbivorous organisms that can ingest Cry proteins from genetically engineered Bt-crops depending on their feeding behaviour. Consequently, they might be directly affected by non-target Bt-protein action and more importantly serve as a source of Cry protein exposure to beneficial predatory arthropods. During a three year field study, we surveyed the community of Auchenorrhyncha in Diabrotica-resistant Bt-maize DKc5143-Bt (event MON88017), its near-isogenic line and two conventional hybrids using sweep netting and custom made sticky traps. Zyginidia scutellaris (Herrich-Schäffer) (Hemiptera: Cicadellidae) represented more than 60% of all captured individuals, indicating that it is the dominant leafhopper within the maize community. The statistical analysis of Z. scutellaris data using confidence intervals for the ratios of mean abundance showed no consistent differences between the Bt-maize and the near-isogenic cultivar, indicating no negative impact of event MON88017. The two conventional hybrids Benicia and DK315 exhibited differences in terms of Z. scutellaris densities, which were greater than those observed between MON88017 and the near-isogenic line, but also not consistent over the years. Six more species accounted for an additional 39% of all captured specimens, while ten more species were found only as single individuals and can be considered vagrants from neighbouring habitats. These results inform future field work on the non-target impact of Bt-maize on this group of arthropods and monitoring approaches to assess biological control function by surveying herbivore communities.

In Europe, Bt-corn resistant against the European Corn Borer has until now been the only genetically modified plant to be grown commercially. With the advent of the Western Corn Rootworm Bt-corn varieties with resistance against Coleoptera will become important. The cultivation of Bt-plants may have negative impacts on non-target organisms, i.e. all species not explicitly targeted by a given Bt-crop. One prominent non-target group in corn are the herbivorous plant bugs (Heteroptera: Miridae). They are common, abundant and exposed to the Cry-protein. We therefore assessed the potential impact of the cultivation of the Cry3Bb1-expressing Bt-corn variety MON88017 and three conventional varieties on this group. Trigonotylus caelestialium (Kirkaldy) was the most abundant plant bug at the experimental field. There was no evidence for a negative impact of MON88017 on this species, despite its considerable exposure to Cry3Bb1 demonstrated with ELISA. The conventional corn varieties, however, had a consistent and significant influence on the field densities of this species over all three growing seasons.

BACKGROUND: Insect-resistant transgenic corn is meeting a growing adopt ion in Europe. Corn is also the major substrate for biogas production, which has vastly increased in recent years. In areas with high insect pest pressure Bt-corn silage will consequently be fed into biogas production facilities. To assess the potential risks of transgenic plants as energy crops we investigated the fate of the coleopteran-specific protein Cry3Bb1 from MON88017 corn in the utilization chain of a farm-scale biogas production facility using ELISA. RESULTS: The mean Cry3Bb1 protein content in chaffed MON88017 plant material was 15 µ gg −1 .I n silage the content decreased rapidly, with less than 20ng g −1 detectable after 8months. From the start of fermentation in the biogas reactor, only trace amounts of Cry3Bb1 could be detected. Conventional corn harvested alongside MON88017 with the same equipment showed a presence of transgenic plant material of around 0.5%. Analyses performed at two laboratories showed consistent and systematic differences in the concentrations of Cry3Bb1 measured with ELISA due to methodical differences. CONCLUSIONS: An extensive degradation of Cry3Bb1 was observed in silage despite differences in ELISA measurements. The potential risk associated with the use of MON88017 silage is discussed on this basis.  2008 Society of Chemical Industry