Research and farm programs should focus on long-term solutions for farmers

Farm Forum

WASHINGTON — Farmers across the United States are battling herbicide-resistant “superweeds,” and the problem may get worse before it gets better. According to a policy brief from the Union of Concerned Scientists (UCS), the resistant weed epidemic now affects more than 60 million acres of U.S. cropland, increasing farmers’ costs and leading to the use of older, 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 costly and highly problematic for farmers,” said Doug Gurian-Sherman, senior scientist with the UCS Food & Environment Program. “And instead of helping farmers, agribusiness’s proposed solutions would make the problem even 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 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.

But these benefits were short lived and are being reversed as weed species have evolved resistance to glyphosate, the active ingredient in Roundup. 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 now higher than it was before Roundup Ready crops came along.

Superweeds are destructive and costly for farmers. Some herbicide-resistant weeds can reach eight feet in height and the tough stems damage farm equipment. A single plant produces hundreds of thousands of seeds spread by the wind. Removing these weeds by hand is sometimes the only option, and an expensive one. Superweeds steal nutrients from the crops. Ultimately these weeds reduce yields, overall productivity, lead to tillage that harms the soil, and reduces farmers’ profits.

“Farmers need real, long-term solutions, but the seed companies’ answer is more of the same—a new generation of crop varieties engineered to withstand older, more toxic herbicides, such as dicamba and 2,4-D,” said Gurian-Sherman. “It’s a move that will sell more products, but it won’t help farmers in the long run.”

In fact, these next generation herbicide-tolerant crops are likely to exacerbate the problem, speeding up the development of weeds that are resistant to multiple herbicides. And if weeds resistant to glyphosate become resistant to dicama 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.

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 can settle on farm fields far from where they were applied. And they 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.

By contrast, farming practices based on the science of agroecology and adapted to fit the needs of farmers in particular areas can help combat weeds while dramatically reducing the need for herbicides. Recent research at Iowa State University, among other studies, has shown that the use of cover crops and more complex crop rotations can cut herbicide use by more than 90 percent, while maintaining or increase farmers’ profits. But current farm policies aren’t doing enough to help farmers adopt and perfect such practices.

UCS recommends policy changes such as increased funding for the U.S. Department of Agriculture’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, public policies and research dollars should support practices and systems that will provide long-term benefits for American farmers and consumers.”