Fresh calls for a review into the long-term effects of GM crops on insect populations have been made after a 10-year study of Bt cotton crops in China revealed a surge in pest numbers, reports Nature News and The Guardian.
Research carried out by researchers at the Chinese Academy of Agricultural Sciences in Beijing* has revealed that millions of hectares of farmland in northern China have been struck by infestations of bugs following the widespread adoption of Bt cotton, an engineered variety made by Monsanto. The Beijing team says the findings “highlight a critical need” for better ways of predicting the potentially damaging knock-on effects of GM crop planting.
The GM cotton plants are modified to produce a toxin from the bacteria Bacillus thuringiensis (Bt) that is deadly to the bollworm, a highly destructive moth larvae. The ‘built-in’ pesticide is intended to reduce the use of conventional spraying, cutting costs and reducing the hazard of poisoning.
Now, the Beijing team — led by entomologist Kongming Wu — has revealed a highly disturbing unintended consequence of the widescale planting of Bt cotton crops — a surge in the numbers of other bugs. For example, numbers of mirid bugs (insects of the Miridae family), previously only minor pests in northern China, have increased 12-fold since 1997 when GM cotton planting began.
Environmental campaigners say the study adds to evidence that GM crops are not the environmental ‘magic bullet’ manufacturers have led farmers to believe they are.
Kirtana Chandrasekaran, a food campaigner at Friends of the Earth, told The Guardian: “This is a massive issue in terms of the environment, but also in terms of costs for the farmer. The plan with GM crops was to reduce costs and environmental impact, but neither of these things seems to be happening, because over time, nature takes its course, and that was bound to happen. The supposed benefits in yield can be cancelled out by unintended consequences like this.”