Scientists call for GM review after surge in pests around cotton farms in China

Ian Sample in the Guardian (UK): Scientists are calling for the long-term risks of GM crops to be reassessed after field studies revealed an explosion in pest numbers around farms growing modified strains of cotton. The unexpected surge of infestations "highlights a critical need" for better ways of predicting the impact of GM crops and spotting potentially damaging knock-on effects arising from their cultivation, researchers said.

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 the US biotech giant, Monsanto. Outbreaks of mirid bugs, which can devastate around 200 varieties of fruit, vegetable and corn crops, have risen dramatically in the past decade, as cotton farmers have shifted from traditional cotton crops to GM varieties, scientists said.

Traditional cotton famers have to spray their crops with insecticides to combat destructive bollworm pests, but Bt cotton produces its own insecticide, meaning farmers can save money by spraying it less. But a 10-year study across six major cotton-growing regions of China found that by spraying their crops less, farmers allowed mirid bugs to thrive and infest their own and neighbouring farms.

The infestations are potentially catastrophic for more than 10m small-scale farmers who cultivate 26m hectares of vulnerable crops in the region studied….

Electron microscope image of a mirid bug (family Miridae), from Darmouth College