Biotech has failed to slow Pesticide Usage

[Timber Loftis]

Biotechnology
Added Use of Genetically Engineered Crops
Has Failed to Slow Pesticide Use, Study Says

Increasing use of genetically engineered crops has failed to slow the use of pesticides in the United States and has in fact coincided with an increasing use of chemicals applied to many crops, according to a study released Nov. 30 by the Northwest Science and Environmental Policy Centre.
Total pesticide use has increased 50.6 million pounds over an eight-year period beginning in 1996--the first year genetically engineered crops were adopted in the U.S.--in part because the increasing popularity of genetically modified crops has triggered higher resistance, requiring increased rates of application, according to the study.

The study was conducted by Benbrook Consulting Services and funded by a range of groups critical of genetically modified crops, including the Union of Concerned Scientists and the Organic Farming Research Foundation.

The study authors acknowledged that the first three years of commercial growth in the modified crops produced a reduction in total pesticide use, but said that decrease was offset "by a massive increase" in pesticide use in more recent years, beginning in 2001. The study, Impacts of Genetically Engineered Crops on Pesticide Use in the United States: The First Eight Years was compiled using U.S. Department of Agriculture figures on annual pesticide use applied to corn, soybeans, and cotton as well as USDA figures that compile the totals for the acreage devoted to such genetically engineered crops.

Those three crops account for nearly all of the acreage of genetically engineered crops in the United States and include herbicide tolerant (HT) corn, soybeans, and cotton as well as bacillus thuringiensis (Bt) transgenic corn and cotton, according to the study.

HT crops allow farmers to spray herbicides over the top of growing plants to control weeds while leaving crops unharmed. By contrast, crops engineered with Bt product a natural bacterial toxin that attacks insects.


Reductions Offset

Such Bt transgenic varieties have led to a reduction in pesticide use by an estimated 19.6 million pounds over the eight-year period, according to the study.
But herbicide tolerant crops have increased pesticide use by 70 million pounds, as HT crops have triggered resistance in weeds, leading to a cycle of increased rates of herbicide application, the study said. The 50.6 million pounds is thus the net increase in pesticide use calculated by the study for the eight-year period.

"The pounds of herbicides required to achieve acceptable weed control is rising on most farms planting herbicide tolerant varieties," according to the study. But farmers continue to save money using the HT varieties because the price of herbicides has dropped dramatically since 1996, the study said.

While the seed price for HT varieties has increased in recent years, they have still become less expensive to grow "largely because the price of herbicides containing glyphosate has fallen from around $12.00 per acre treated when HT crops were first introduced to less than $6.00 per acre today," the study said. Some 400 million acres of HT crops have been planted since 1996, about three-quarters of it soybeans.

The study is available at http://www.biotech-info.net/technicalpaper6.html on the World Wide Web.

Copyright © 2003 by The Bureau of National Affairs, Inc., Washington D.C.