GM cotton protects insect predators

Editor's summary

Transgenic crops producing insecticidal proteins derived from Bacillus thuringiensis (Bt) have proved effective in controlling bollworm and reducing the need for pesticides in cotton crops in China. This study of Bt crop performance at sites across northern China identifies a decrease in aphid pests and a marked increase in the numbers of ladybirds, lacewings and spiders — natural enemies of insect pests — compared with conventional crops. There is also evidence that these predators thrive in neighbouring non-transgenic maize, soyabean and peanut crops. These results suggest that Bt cotton can promote biological control in agricultural ecosystems by decreasing insecticide use and increasing predator populations.