WASHINGTON (Dec. 11, 2013) – A plague of out-of-control weeds is cropping up in farm fields across the country. According to a policy brief from the Union of Concerned Scientists (UCS), this epidemic of “superweeds”—weeds that have developed resistance to a common herbicide that once kept them in check—now affects more than 60 million acres of U.S. cropland, wreaking environmental havoc, increasing farmers’ costs, and promoting the use of more toxic herbicides.
The brief, “The Rise of Superweeds – and What to Do About It,” analyses the problem with existing and proposed technology fixes, and lays out more sustainable ways to control resistant weeds. These alternatives often have multiple benefits for farmers and the public, and need more emphasis from policy makers and the research community
“It sounds like a bad sci-fi movie or something out of The Twilight Zone. But ‘superweeds’ are real and they’re infesting America’s croplands,” said Doug Gurian-Shermand, senior scientists with the UCS Food & Environment Program and author of the paper. “Overuse of Monsanto’s ‘Roundup Ready’ seeds and herbicides in our industrial farming system is largely to blame. And if we’re not careful, the industry’s proposed ‘solutions’ could make this epidemic much worse.”
When Monsanto’s “Roundup Ready” product line went on the market 17 years ago, it was supposed to reduce herbicide use. This convenient system of engineered seeds designed to work with the company’s Roundup herbicide enabled farmers to apply herbicides after crops were growing to kill weeds while leaving their crops unharmed. Farmers enthusiastically adopted these products as they saved time and made weed control easier. And initially, overall herbicide use declined.
The benefits were short lived. Weed species began evolving resistance to glyphosate, the active ingredient in Roundup, in the United States within five years. Fifty percent of U.S. farmers surveyed report glyphosate-resistant weed infestations. In the Southeast, more than 90 percent of cotton and soybean farmers are affected. Today, 24 species of weeds have developed resistance, and as a result, overall herbicide use is far higher than before Roundup Ready crops. If the Roundup Ready crops had never been planted, it is estimated farmers would have eliminated 404 million pounds of pesticides.
The U.S.’s outdated farming system is also part of the problem. For years, farming policies have encouraged farmers to plant the same crop year after year. This system, called monoculture, provides a superb breeding ground for weeds, and has accelerated the development of resistance.
Some resistant weeds can grow eight feet tall and the tough stems damage farm equipment. Removing them by hand can be the only option, and an expensive one. These weeds steal nutrients from the crops, which reduces yields, overall productivity, and farmers’ profits.
“Monsanto and other agribusiness companies are now touting herbicide-resistant crops engineered to withstand older, more toxic herbicides, such as dicamba and 2,4-D, as the ‘solution.’ These new herbicides will certainly exacerbate the problem, but increase the companies’ bottom lines,” said Gurian-Sherman. “It’s a highly risky move. Increased herbicides use on the new engineered crops will speed up weed resistance, leaving no viable herbicide alternatives. This is a dangerous chemical cocktail, that when combined with the current farming system, it’s a recipe for disaster.”
In fact, these next generation herbicide-tolerant crops are likely to speed up the development of weeds that are resistant to multiple herbicides. If weeds resistant to glyphosate become resistant to dicamba or 2,4-D, and several other major herbicides, there would be no other good alternative herbicides to fight what would be the ultimate superweeds. There are no silver bullet herbicides in the chemical pipeline to bail farmers out when current herbicides fail.
Moreover, dicamba and 2,4-D pose additional risks to people and nearby crops. These herbicides have been linked to increased rates of certain diseases, including non-Hodgkin’s lymphoma, in farmers and farm workers. They are prone to drifting on the wind and dispersing into the air after application, and consequently, the herbicides can settle far from where they were applied. These herbicides are extremely toxic to many of the most common fruit and vegetable crops, as well as to plants that provide food and habitat for pollinators and other beneficial insects.
There is a better way to help farmers combat superweeds, through public policies that provide incentives for “healthy farming” practices based on the science of agroecology. These practices include rotating crops and planting cover crops. If implemented, such practices could reduce herbicides use by more than 90 percent, while keeping weeds in check and even increasing farmers’ profits.
UCS recommends increased funding for the USDA’s Conservation Stewardship Program, which offers financial incentives for farmers using sustainable weed control methods. More resources should also be directed toward multidisciplinary research on integrated weed management strategies, and technical assistance to help farmers adopt them. The new generation of herbicide resistant crops should not be approved without adequate safeguards to protect the public and reduce the possibility of more resistant weeds.
“Fighting fire with fire will only result in a conflagration – farmers deserve solutions that will not fail in a few years, and land them in an even deeper hole,” said Gurian-Sherman. “Instead of favoring the same industrial methods and genetically engineered products that got farmers into this mess, public policies should promote healthy farming practices that can produce long-term benefits for American farmers, consumers, and the natural resources we all depend upon.”