(Beyond Pesticides, November 18, 2009) A report released yesterday and authored by Charles Benbrook, PhD, chief scientist at The Organic Center (TOC), finds that the rapid adoption by U.S. farmers of genetically modified corn, soybeans and cotton has promoted increased use of pesticides, an epidemic of herbicide-resistant weeds, and more chemical residues in foods.
The report, â€śImpacts of Genetically Engineered Crops on Pesticide Use in the United States: The First Thirteen Years,â€ť explores the impact of the adoption of genetically modified (GM) corn, soybean, and cotton on pesticide use in the United States, drawing principally on data from the U.S. Department of Agriculture (USDA). The most striking finding, is that GM crops have been responsible for an increase of 383 million pounds of herbicide use in the U.S. over the first 13 years of commercial use of GE crops (1996-2008). The report identifies, and discusses in detail, the primary cause of the increase–the emergence of herbicide-resistant weeds.
The steep rise in the pounds of herbicides applied with respect to most GM crop acres is not news to farmers. Weed control is now widely acknowledged as a serious management problem within GM cropping systems. The rise in herbicide use comes as U.S. farmers increasingly adopt corn, soy and cotton that have been engineered with traits that allow them to tolerate dousings of weed killer. The most popular of these is known as “Roundup Ready” for its ability to sustain treatments with Roundup herbicide (glyphosate) and are developed and marketed by industry leader Monsanto. However, the report states that a key problem resulting from the increase in herbicide use is the emergence of “super weeds,” which are difficult to kill because they have become resistant to the herbicides. In 2008, GM crop acres required over 26% more pounds of pesticides per acre than acres planted to conventional varieties. The report projects that this trend will continue as a result of the rapid spread of resistant weeds.
“With glyphosate-resistant weeds now infesting millions of acres, farmers face rising costs coupled with sometimes major yield losses, and the environmental impact of weed management systems will surely rise,” said Dr. Benbrook.
Farmers have become increasingly critical of both GM seed, as it goes up in price, and herbicides like Roundup, as ‘superweeds’ become prevalent in treated fields. The growth of pigweed, which can quickly reach widths of six inches at the stalk, and other invasive, glyphosate-resistant species increases farmers reliance on more high-risk herbicides, including 2,4-D, dicamba and paraquat, and has resulted in a return to hand harvesting and even abandoning of fields.
Noteworthy is that while herbicide use has climbed, insecticide use has dropped because of biotech crops. The adoption of GM corn and cotton that carry traits resistant to insects has led to a reduction in insecticide use by 64 million pounds since 1996, according to the study.
The report also criticizes the agricultural biotechnology industry for claiming that higher costs for GM seeds are justified by multiple benefits to farmers, including decreased spending on pesticides. The report states that biotech corn seed prices in 2010 could be almost three times the cost of conventional seed, while new enhanced biotech soybean seed for 2010 could be 42 percent more than the original biotech version. Meanwhile, USDA, which continues to collect farm-level data on pesticide applications, has been essentially silent on the impacts of GM crops on pesticide use and the integrity of U.S. agriculture for almost a decade.
“This report confirms what we’ve been saying for years,” said Bill Freese, science policy analyst for the Center for Food Safety. “The most common type of genetically engineered crops promotes increased use of pesticides, an epidemic of resistant weeds, and more chemical residues in our foods. This may be profitable for the biotech/pesticide companies, but it’s bad news for farmers, human health and the environment.”
Without performance, costs, and human and environmental risk assessments associated with GM crops, the report concludes, â€śU.S. agriculture is likely to continue down the road preferred by the biotechnology industry, a path that promises to maximize their profits by capturing a larger share of farm income, and limit the ability of plant breeders and other agricultural scientists to address other pressing issues of goals importance to society as a whole.â€ť
For more Information on GM crops visit Beyond Pesticidesâ€™ Genetic Engineering program page