(Beyond Pesticides, June 3, 2011) According to the 2010 Agricultural Chemical Use Report released last week by the U.S. Department of Agriculture’s (USDA) National Agricultural Statistics Service (NASS), use of the herbicide glyphosate, associated with genetically engineered (GE) crops, has dramatically increased over the last several years, while the use of other even more toxic chemicals such as atrazine has not declined. Contrary to common claims from chemical manufacturers and proponents of GE technology that the proliferation of herbicide tolerant GE crops would result in lower pesticide use rates, the data show that overall use of pesticides has remained relatively steady, while glyphosate use has skyrocketed to more than double the amount used just five years ago.
The 2010 Agricultural Chemical Use Report shows that, in the states surveyed, 57 million pounds of glyphosate were applied last year on corn fields. Ten years prior, in 2000, this number was only 4.4 million pounds, and in 2005, it was still less than half of current numbers at 23 million pounds. Intense corn growing regions have experienced an even greater increase in glyphosate applications. Glyphosate use in the state of Nebraska increased by more than five times in just seven years, going from 1.25 million pounds applied in 2003 to more than seven million pounds last year.
GE proponents have often said that, even if farmers are increasingly reaching for glyphosate, this simply means that they are using less of more toxic weed killers like atrazine. However, the data tell a different story. In 2000, 54 million pounds of atrazine were applied across surveyed states. With glyphosate use increasing by more than five times between 2000 and 2005, atrazine use should have significantly declined over this period. However, the total pounds applied actually increased by more than three million, to 57.4 million total pounds applied across surveyed states in 2005. By 2010, atrazine use had just barely declined, with 51 million pounds still being applied, only slightly less than the 57 million pounds of glyphosate applied. Such widespread use of atrazine is a concern due to the chemical’s links with serious human health effects, including birth defects and disruption of the endocrine and reproductive systems. Additionally, it is a major threat to wildlife as it can harm the immune, hormone, and reproductive systems of aquatic species.
The rise in glyphosate applications has almost certainly come as a result of farmers increasingly planting GE crops such as corn and soybeans, which are engineered to be resistant to the chemical. In this way, farmers can apply the chemical on a vast scale across their fields while not having to be careful that they don’t hit their crops. The most common commercial line of these GE seeds is Monsanto’s line of Roundup Ready crops, named for the company’s glyphosate formulation Roundup, though there are also several other commercially available products, such as Bayer CropScience’s GlyTol technology.
Glyphosate is a general herbicide used for eradication of broadleaf weeds. It has been linked to a number of serious human health effects, including increased cancer risk and neurotoxicity as well as eye, skin, and respiratory irritation. One of the inert ingredients in product formulations of Roundup, polyoxyethyleneamine (POEA), is of particular concern due to its toxicity to aquatic species as well as instances of serious human health effects from acute exposure.
Coupled with the dramatic rise in glyphosate applications has been the spread of wild plant species that are resistant to the herbicide. Over-application and over-reliance by farmers on glyphosate to solve all of their weed problems has led to the proliferation of so-called “superweeds” which have evolved to survive the treatments through repeated exposure. The most common species which have evolved these traits include pigweed (palmer amaranth), mare’s tail, and ryegrass. The spread of resistance is what has led farmers to increasingly rely on more toxic alternative mixtures including weed killers like atrazine. There has also been an increased push by chemical companies to engineer seed varieties that are resistant to multiple herbicide treatments, such as glyphosate and 2,4-D, or glyphosate and acetochlor.
As researchers scramble to find new ways of chemically coping with increased weed resistance, they overlook the glaring fact that there already exist alternative systems such as organic farming, which erases the need for these drastic measures through its systemic pest preventon approaches. Organic farming can be at least as productive as conventional, chemically-reliant farming while having none of the toxic side effects which create significant risks to ecosystems and human health. To learn more, see our page on organic food and agriculture.
Currently, there are commercially available glyphosate tolerant seed varieties for corn, soybeans, canola, sorghum, and cotton. Also, recently approved by the USDA were Roundup Ready versions of alfalfa and sugar beets. Due to serious questions regarding the integrity of USDA’s environmental evaluations, public interest groups, including Beyond Pesticides, have filed suit against the agency to stop its full deregulation of GE alfalfa.