U.S. FARMERS CAUGHT IN A TREADMILL WITH GM HERBICIDE-RESISTANCE CROPS
A new study by U.S. scientists warns that agricultural weed management through herbicide-resistant crops is an unsustainable pathway. Over the years, Monsanto has heavily promoted the massive use of its glyphosate-based Roundup herbicide in conjunction with its genetically modified (GM) Roundup Ready crops while denying that weed resistance would ensue. By 2012, however, the reported acreage infested with glyphosate-resistant weeds in the U.S. had risen to 61.2 million acres from 32.6 million acres in 2010.
In response, agri-business corporations are developing crops that are genetically engineered to be resistant to both glyphosate and synthetic auxin herbicides such as 2,4-D and dicamba. Scientists have documented that non-target terrestrial plant injury was 75 to 400 times higher for dicamba and 2,4-D, respectively, than for glyphosate.
The researchers categorically state that the continual insertion of more genes into crops is not a sustainable solution to herbicide resistance and call this the ‘genetic modification treadmill’, similar to the ‘pesticide treadmill’ that was introduced in the mid-20th century. They warn that this ‘single-tactic approach’ is likely to make the problem worse by increasing the severity of resistant weeds as well as will facilitate a significant increase in herbicide use with related potential harmful effects.
The report discusses these risks and presents alternatives for research and policy. In particular, the team recommends integrated weed management characterized by reliance on multiple weed management approaches that are firmly underpinned by ecological principles and which has been shown to reduce herbicide use by as much as 94%.
With best wishes
NAVIGATING A CRITICAL JUNCTURE FOR SUSTAINABLE WEED MANAGEMENT
David A. Mortensen, J. Franklin Egan, Bruce D. Maxwell, Matthew R. Ryan, Richard G. Smith. Navigating a Critical Juncture for Sustainable Weed Management. BioScience, Vol. 62, No. 1 (January 2012), pp. 75-84. http://www.jstor.org/stable/10.1525/bio.2012.62.1.12.
Agricultural weed management has become entrenched in a single tactic—herbicide-resistant crops—and needs greater emphasis on integrated practices that are sustainable over the long term. In response to the outbreak of glyphosate-resistant weeds, the seed and agrichemical industries are developing crops that are genetically modified to have combined resistance to glyphosate and synthetic auxin herbicides. This technology will allow these herbicides to be used over vastly expanded areas and will likely create three interrelated challenges for sustainable weed management. First, crops with stacked herbicide resistance are likely to increase the severity of resistant weeds. Second, these crops will facilitate a significant increase in herbicide use, with potential negative consequences for environmental quality. Finally, the short-term fix provided by the new traits will encourage continued neglect of public research and extension in integrated weed management. Here, we discuss the risks to sustainable agriculture from the new resistant crops and present alternatives for research and policy.
*Scientists have documented that non-target terrestrial plant injury was 75 to 400 times higher for dicamba and 2,4-D, respectively, than for glyphosate.
Herbicide-resistant weeds are becoming a more widespread problem in the United States. Although herbicide resistance has most commonly occurred in the south in cotton and soybeans, it is increasing in other regions as well. According to a team of agricultural researchers from Pennsylvania State University, University of New Hampshire and Montana State University, too much reliance on glyphosate-type herbicides for weed control on U.S. farms has created a dramatic increase in the number of genetically-resistant weeds.