Transgenic cotton expressing Mpp51Aa2 does not adversely impact beneficial non-target hemiptera in the field

Abstract

The modified Mpp51Aa2 (previously Cry51Aa2.834_16) insecticidal crystal protein derived from Bacillus thuringiensis (Bt) protects against feeding damage caused by targeted hemipteran and thysanopteran pests, and was transformed in cotton to produce the MON 88702 cotton event. As part of an ecological risk assessment, we evaluated the relative impact of MON 88702 on the abundance of predatory Hemiptera, compared to a conventional control. Field trials were established in 2018 at six sites within cotton production regions of the U.S. Specific arthropod populations in MON 88702 and its conventional control (DP393), grown under different insecticide regimes within a randomized complete block design, were assessed at each field site. Arthropod samples were collected 10 times, starting at early squaring and weekly thereafter, over the course of the season at each site, using vertical beat sheets, sweep nets and visual counts. Across the sites, no significant differences were detected in abundance of predatory Hemiptera (Orius spp., Geocoris spp., Nabis spp., and Zelus spp.) between unsprayed MON 88702 and the unsprayed conventional control. In contrast, a broad-spectrum insecticide treatment significantly reduced the abundance of these and other taxa. Consistent with laboratory studies, the lack of differences between unsprayed MON 88702 and the unsprayed control indicates that the cultivation of MON 88702 is unlikely to adversely impact the predatory function associated with these beneficial Hemiptera in the cotton agro ecosystem.