At least 21 weed species have developed resistance to Monsanto’s Roundup herbicide, according to a new series of studies released by Weed Science. So-called “super-weeds” are now developing resistance to alternative herbicides.
And new occurrences of resistance are being noted in varying weed species and locations.
In one study, a soybean field in continuous production over 6 years showed reduced control of johnsongrass — a plant in the grass family considered a weed — with the recommended application rate of glyphosate.
Fast Company’s Michael J. Coren notes the same selection pressure creating bacteria resistant to multiple antibiotics is leading to the rapid evolution of plants that survive modern herbicides.
If the trend continues, writes Coren, yields could drop and food costs climb as weeds grow more difficult to uproot.
“The herbicide resistance issue is becoming serious,” the journal’s editor, William K. Vencill, said. “It is spreading out beyond where weed scientists have seen it before.”
Coren notes that the “super-strains of plants like pigweed — which grows three inches a day and is tough enough to damage farm machinery — have emerged, which may dramatically reduce the options for farmers to control them.
“The alternatives are usually more dangerous chemicals or plowing and mulching fields, undermining many of the environmental benefits biotech crops are supposed to offer”.
Not only are the environmental benefits undermined, but all these additional chemicals and extra plowing and mulching adds to the cost of crops that are eventually passed on to the consumer.
In 2010, congressional witnesses documented how resistance has spread across U.S. farm fields, in particular, resistance to glyphosate, the herbicide used for Roundup Ready crops.
“When the USDA allowed the commercialization of Roundup Ready crops, the results were supposed to be bigger yields, better profits for farmers and less pollution from herbicide,” said Rep. Dennis Kucinich, D-Ohio, chairman of the Subcommittee on Domestic Policy of the Oversight and Government Reform Committee.
Last Year, David Mortensen, a weed ecologist at Penn State University said glyphosate [Monsanto's Roundup herbicide] resistance in the United States has spread from 2.4 million acres in 2007 to more than 11 million acres at present.
“A larger issue looms with respect to glyphosate-resistant weeds,” said Andrew Kimbrell, executive director of the Washington, D.C.-based Center for Food Safety, who called the glyphosate resistance issue just the latest failure of the USDA on biotech issues.
“Weed scientists are cautioning that should weeds develop resistance to multiple herbicide varieties, no solution is readily foreseeable.”
“The history of USDA’s oversight of genetically engineered crops is littered with failures,” said Kimbrell, calling for more oversight of biotech firms by the government. “Numerous government assessments have found USDA’s oversight severely lacking.”
In recent years, the USDA has ignored reports of crop contamination and suggestions to monitor resistant weeds, Kimbrell said. He added that one weed scientist called glyphosate-resistant weeds “potentially the worst threat to cotton since the boll weevil” because of the crop’s dependence on glyphosate.