The Biosafety Research Group at Agroscope led by researchers Jörg Romeis and Michael Meissle has conducted a review of literature on genetically modified (GM) crops that produce several insect-active Bacillus thuringiensis (Bt) toxins simultaneously. The experts concluded that the toxins did not pose an increased risk for non-target organisms such as beneficials.

Bt crops produce proteins that are toxic to certain insect pests. Increasingly, Bt crop varieties are engineered to produce a number of Bt toxins simultaneously to control target pests more efficiently, expand the range of target pests, and slow down the development of resistance. It has been a concern that Bt crops could pose an increased risk for non-target organisms, since the individual proteins produced might interact with one another.

Jörg Romeis and Michael Meissle conducted a systematic literature search of all major databases in order to spot evidence of interactions between Bt toxins that might cause unexpected damage to non-target organisms. They checked approximately 2,300 literature references for relevant results and identified 58 scientific publications with results from laboratory or field trials. The laboratory studies were conducted with a total of 35 insect species from 24 families and 11 orders. Field trials recording the frequencies of insects chiefly in Bt maize and Bt cotton were carried out in 5 and 7 countries, respectively.

The researchers did not find evidence in the literature that Bt toxins in combination have a different action spectrum than the individual proteins. They concluded that genetically engineered plants containing combined Bt toxins are as safe for non-target organisms as plants with a single Bt toxin.

For more details, read the news article in Agroscope.