Scientists call for GM review after surge in pests around cotton farms in China.
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.
The findings mark the first confirmed report of mass infestations arising as an unintended consequence of farmers using less pesticide – a feature of Bt cotton that was supposed to save money and lessen the crops' environmental impact. The research, led by Kongming Wu at the Chinese Academy of Agricultural Sciences in Beijing, is published in the US journal, Science.
"Our work highlights a critical need to do ecological assessments and monitoring at the landscape-level to better understand the impacts of GM crop adoption," Dr Wu told the Guardian.
Environmental campaigners seized on the study as further evidence that GM crops are not the environmental saviour that manufacturers have led farmers to believe.
"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 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," said Kirtana Chandrasekaran, a food campaigner at Friends of the Earth.
In the past decade, farmers in India and elsewhere have noticed that herbicide-tolerant GM crops have developed resistance to pesticide sprays, again reducing the benefits of the crops, Chandrasekaran said. "Reliance on GM is not sustainable. We need to get back to using local varieties of crops that are adpted to the conditions, and develop an integrated system of pest management."
Bt cotton is modified to produce a natural insecticide that is made by a soil bacterium called Bacillus thuringiensis. The toxin specifically targets bollworms, which can devastate cotton yields.
We really do seem to lack any learning curve whatsoever. Insects are the end product of hundred of millions of years of evolution. They are highly adapted and adaptable organism. They are going to find a way to survive because that is how natural selection works.
The arrogance of our species is amazing. We believe our over-sized and over-rated brains trumps forces of nature that been at work for hundreds of million years. It does not work that way. The very premise of GM has always been a lie. Our short-sighted and profit-driven attempts to bend nature to our wills; to make the power of genetics serve our transient wishes is a fools errand.
Unlike human governmental entities Monsanto has no way to lobby Mother Nature to change her rules. There is no way to game this particular system. Biology has a billion year head start on corporate, crony capitalism. Transnational corporations like Monsanto can assault the natural order all they want, biology has defense in depth. Remember folks, nature still holds the trump card of extinction; it can always rid itself of those pesky, troublesome hairless apes.