Farming's genetic revolution has yet to m...( Most American farmers who have turned...)

Most American farmers who have turned to genetically engineered crops seem to be getting yields no better than farmers who grow traditional varieties. They also appear to be using similar quantities of pesticides.

Last week, the US Department of Agriculture released figures for 1997 and 1998 on the performance of modified cotton, maize and soya beans. Some of the genetically modified crops produce an insecticide called Bt. Others are modified to tolerate high doses of the herbicide glyphosate.

To study the use of pesticides on these crops, the USDA divided the country into various different regions. In seven of the 12 combinations of crops and regions, farmers using modified crops had had to add the same quantities of pesticides to their fields as those growing non-modified crops. To study yields, the USDA looked at 18 crop/region combinations. In 12 of them, yields of modified crops were no better.

Companies promoting genetically modified crops have argued that farmers growing them will benefit from improved yields and reduced pesticide costs. And they are taking heart from some improvements seen within the USDA's analysis. In one region in the Midwest, for instance, farmers planting Bt maize had yields 30 per cent higher than those growing ordinary crops. "The analysis shows that crop biotechnology works," claims Margaret Spike of the American Crop Protection Association in Washington DC.

USDA officials, however, admit that at face value the figures don't provide much support for those who argue that genetic engineering will bring about a revolution in agriculture. But USDA economic analyst Ralph Heimlich warns that the study could be misleading. For instance, farmers who have embraced modified crops might have had worse problems with pests to begin with.

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Contact: Claire Bowles
claire.bowles@rbi.co.uk
44-171-331-2751
New Scientist
7-Jul-1999