Early falls in pesticide use on GM crops in the United States have been replaced by rapid increases according to study

Pesticide-use in the US has increased significantly since the introduction of genetically modified (GM) crops, according to a new report. GM crop varieties have quickly come to dominate production of maize, soybean and cotton in the US with more than 1.3 billion acres planted between 1996-2008.

Research from an alliance of environmental groups has found that the switch to GM crops has led to an extra 318 million pounds of pesticides being used by farmers. The report, 'Impacts of Genetically Engineered Crops on Pesticide Use: The First Thirteen Years' was commissioned by The Organic Center and the Centre for Food Safety.

Herbicide-use rising
It found that the adoption of GM BT corn and cotton had led to a reduction in insecticide use, compared to what is likely to have been applied to conventional crops, of 64 million pounds between 1996-2008. But the uptake of other GM crops resistant to herbicides in the same period led to an increase in herbicide use of 382 million pounds. That left an overall figure of 318 pounds of additional pesticides being used.

The rate of increase in pesticide use is rising too. After falling in the early years (1996-1998) by between 1 and 2 per cent, it increased by 20 per cent in 2007 and 27 per cent in 2008. The report puts this down to the emergence of weeds resistant to the pesticides.

Weed resistence
'A rise in herbicide use is not news to farmers, but it is to the public which still harbors the illusion, fed by misleading industry claims and advertising, that biotechnology crops are reducing pesticide use,' says the report. 'Such a claim was valid for the first few years of commercial use of GM corn, soybeans, and cotton. But, as this report shows, it is no longer.'

The report goes on to criticise biotech firms for not addressing the issue of pesticide-resistant weeds. 'There is no serious dispute that RR [Monsanta's RoundUp Ready crops that can withstand being sprayed with the company's Roundup herbicide] crops have been popular...but they have fostered unprecedented reliance on glyphosate for weed control, and over-reliance has spawned a growing epidemic of glyphosate-tolerant and resistant weeds.

'A large portion of industry R&D investments are going into the development of crops that will either withstand higher rates of glyphosate applications, or tolerate applications of additional herbicides, or both.  'In short, the industry’s response is more of the same,' concludes the report.

(The Ecologist, 17/11/2009)