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- 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.
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- 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.
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- 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.
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- 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.
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- 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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