Pests invade GM cotton crops in China

The wide scale adoption of genetically modified (GM) cotton crops in China has led to an explosion of insect pests, according to a study conducted by researchers from the Chinese Academy of Agricultural Sciences and published in the journal Science.

"This is a massive issue in terms of the environment, but also in terms of costs for the farmer," said Kirtana Chandrasekaran from Friends of the Earth. "The plan with GM crops was to reduce costs and environmental impact, but neither of these things seem 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."

Roughly 10 years ago, Chinese cotton farmers widely adopted Monsantos GM Bt cotton, engineered to produce a pesticide in its tissues to deter bollworms. In the new study, researchers monitored levels of insecticide use between 1992 and 2008 and mirid bug populations between 1997 and 2008 at 38 farms in six northern Chinese provinces. The researchers found that after the adoption of Bt cotton, mirid bugs resistant to the Bt pesticide soon began to thrive in the vast cotton monocultures of the provinces of Anhui, Hebei, Henan, Jiangsu, Shandong and Shanxi. This led to a mirid population boom, and the bugs have now started to spill over into the fields of other farmers.

Mirid bugs feed on more than 200 different fruit, vegetable and grain crops.

Chinas mirid explosion is only the most recent example of nature adapting quickly to GM crops, leading to worse conditions than before the modified crops were adopted. In India, farmers have reported the development of pesticide resistance in fields planted with herbicide-tolerant GM crops.

"Reliance on GM is not sustainable," Chandrasekaran said. "We need to get back to using local varieties of crops that are adapted to the conditions, and develop an integrated system of pest management."