Six-year monitoring of non-target arthropods in Bt maize (Cry 1Ab) in the European corn borer (Ostrinia nubilalis) infestation area Oderbruch (Germany)

Abstract

This study was performed in the Oderbruch region, a landscape where Ostrinia nubilalis occurs in high densities. From 2000 to 2005, field pairs (half-fields) planted with Bt maize (Cry 1Ab) and a conventional maize variety, respectively, were investigated using different monitoring methods (visual counts, wholeplant harvesting and pitfall trapping) to determine densities of taxa on plants, activity densities and diversity of ground-dwelling arthropods. A total of 48 taxa were determined in counts and 90 in whole-plant harvests; 75 carabid species and 62 spider species were identified by pitfall trapping. Density comparisons of different taxa, such as aphids, thrips, heteropterans, aphid specific predators, spiders and carabids, revealed a few significant differences for specific taxa but no general tendencies during the six years. Canonical corresponding analyses revealed small but statistically significant differences in community composition between Bt and conventional maize fields. Generally, year-toyear changes in environmental conditions, field characteristics, and population dynamics had much stronger effects on the arthropod community than the use of Bt maize. Three baselines were used for evaluation of findings: (1) mean and variation of a specific variable (e. g. density) in a given conventional maize field, (2) mean and variation of a specific variable in conventional maize fields in the last five years and (3) mean and variation of a specific variable in conventional maize fields within a given year. This methodological approach is tested for suitability for casespecific monitoring.

Arthropod Abundance and Diversity in Transgenic Bt Soybean

“…Our data showed no signiÞcant difference in their abundances in Bt soybean plots compared with those in the recipient cultivar. Our results were consistent with previous data showing that the population densities of aphids and thrips did not differ between Bt and non-Bt maize Þelds by 6-yr survey in Germany (Schorling and Freier 2006). Likewise, no signiÞcant difference was detected between Bt and non-Bt rice Þelds in population densities of six sucking pest species including planthoppers, Sogatella furcifera (Horváth), Nilaparvata lugens (Stål), and Laodelphax striatellus (Fallé n), and three species of leafhoppers, Nephotettix cincticeps (Uhler), Thaia subrufa (Motschulsky), and Recilia dorsalis (Motschulsky) (Chen at al.…”

Postcommercialization Monitoring of the Long-Term Impact of Bt Corn on Non-Target Arthropod Communities in Commercial Farms and Adjacent Riparian Areas in the Philippines

“…In a previous study on long-term monitoring of Bt corn, Schorling and Freier (2006) reported that Bt corn did not have a signiÞcant impact on arthropod community. Similarly, Priestly and Brownbridge (2009) concluded from their 2-yr study that environmental conditions and crop-management practices had the most signiÞcant impact on arthropod community rather than crop type.…”

Impact of Six TransgenicBacillus thuringiensisRice Lines on Four Nontarget Thrips Species Attacking Rice Panicles in the Paddy Field

“…In contrast, Bt maize has not encountered the serious problems with secondary insect pests stemming from experiences with Bt cotton (Hellmich et al 2008). For example, in Germany, no difference in the population densities of aphids, thrips, and heteropterans were found after 6 yr of monitoring nontarget arthropods in Bt maize Þelds (Schorling and Freier 2006). With regard to Bt rice, the problems encountered with Bt cotton are not expected to occur.…”