Non-GMO farmers caught in crossfire of war on herbicide-resistant weeds
By Audrey Alwell, MOSES
Dow AgriScience is pushing for deregulation of its Enlist Duo™ program—herbicide-resistant corn and soybeans genetically engineered to tolerate applications of both 2,4-D and glyphosate. If approved, the amount of 2,4-D used on farms is expected to explode, threatening ecosystems and human health. Organic and non-GMO farming are caught in the crossfire in this escalating war on herbicide-resistant weeds.
The USDA received more than 400,000 comments on its draft Environmental Impact Statement (EIS) for Enlist Duo™ in March. The EIS acknowledged the expected increase in 2,4-D use, but argued that the agency’s regulatory responsibility entails only identifying if the seed itself poses a risk to other plants. The USDA determined that the seed requires no agency oversight and gave Dow a green light.
The Environmental Protection Agency issued its EIS May 2, 2014; the comment period closed June 30. The EPA announced its intent to green light Dow’s new formulation and new use of 2,4-D.
When genetically engineered, herbicide-resistant crops (GE HR) were first introduced, the biotech firms promised a panacea of “easy” and effective weed control coupled with a reduction of pesticide use. The reality, though, is quite different.
Herbicide-resistant crop technology has led to a 527-million-pound increase in herbicide use in the United States between 1996 and 2011. Widespread planting of Dow’s new Enlist corn could trigger more than a 30-fold increase from 2010 levels of 2,4-D use. (Benbrook, 2012)
Widespread use of the herbicide Roundup on Monsanto’s GE “Round-up Ready” crops has led to an epidemic of herbicide-resistant weeds. “Superweeds” developed resistance to glyphosate, the active ingredient in Roundup, leaving farmers desperately trying to fix their “easy” weed control system. Rather than learn from the failings of Roundup Ready crops, the USDA and the EPA are willing to bet the farm and our food system on an even more toxic weapon to fight weeds.
Convenience was the main reason farmers adopted herbicide-resistant crops; this technology provided the ability to farm more land with less labor. (Duffy, 2001) That labor-saving advantage made it possible for farms to “super-size.” These mega-farms are now at a scale that demands ongoing adoption of GE HR technologies.
Science Predicts Repeated Failure
Dow’s Enlist program is being proposed as the solution to Roundup-resistant weeds. However, weed scientists predict that Dow’s crops will generate even more intractable weeds resistant to both glyphosate and 2,4-D.
There are already at least eight weeds resistant to 2,4-D. A population of 2,4-D resistant waterhemp (Amaranthus tuberculatus) has been confirmed in Nebraska. (Benbrook, 2012) North Dakota, Nebraska, and Montana have confirmed cases of kochia resistant to synthetic auxins. Research has shown that these particular biotypes are resistant to dicamba (closely related to 2,4-D) and may be cross-resistant to other Group O/4 herbicides, including 2,4-D. (Heap, 2014)
Spraying 2,4-D and glyphosate onto weeds that are already resistant to one or the other is likely to breed resistance to the additional herbicide, according to Dr. Frank Kutka, manager of the Northern Plains Sustainable Agriculture Society’s Farm Breeding Club.
Yet, the bulk of the pesticide-biotech firms’ research and development efforts are on new crops engineered with resistance to even more herbicides. Two-thirds of GE crops awaiting approval by USDA are resistant to one to three herbicide groups. For example, in addition to soybeans resistant to dicamba and glyphosate, Monsanto has corn and cotton in the pipeline, which are resistant to three herbicides. DuPont has set its sights on a single crop resistant to seven or more herbicides. In the process, these crops will generate substantial profits for pesticide-biotech firms that sell both HR seed and the associated herbicides. (Freese, 2012)
In the peer-reviewed research publication Navigating a Critical Juncture for Sustainable Weed Management, Dr. David Mortensen and colleagues at Pennsylvania State University advise, “Given this critical juncture, it is time to consider the implications of accelerating the transgene-facilitated herbicide treadmill and to rejuvenate our commitment to alternative policies that safeguard agriculture and the environment for the long term.” These weed scientists stress that the short-term fix provided by the new GE HR traits will encourage continued neglect of public research and extension in Integrated Weed Management (IWM). They recommend IWM practices—crop rotation, cover crops, competitive crop cultivars, the judicious use of tillage, and targeted herbicide application—take center stage as part of an integrated approach to weed control. (Mortensen et al, 2012)
Impact on Other Plants
Increasing use of 2,4-D presents a serious threat to non-HR broadleaf plants, including many specialty crops. Both spray and volatilization drift can devastate adjacent ecosystems. 2,4-D is over 300 times more toxic to emerging seedlings and nine times more toxic to growing plants than glyphosate. (Freese, 2012)
According to the label for LV 400 2,4-D Weed Killer, “Susceptible crops include, but are not limited to, cotton, okra, flowers, grapes (in growing stage), fruit trees (foliage), soybeans (vegetative stage), ornamentals, sunflowers, tomatoes, beans, and other vegetables, or tobacco.” (PBI/Gordon Corporation, 2013) Growers of any kind of broadleaf specialty crops will suffer losses.
Human Health Concerns
According to the Center for Food Safety, exposure to 2,4-D has been linked to major health problems that include cancer, liver disease, and Parkinson’s disease. Laboratory studies show that 2,4-D adversely affects the hormonal, reproductive, neurological and immune systems.
Tests have shown that 2,4-D is contaminated with dioxins, a group of highly toxic chemical compounds that bioaccumulate up the food chain. A barely visible speck of the dioxin 2,3,7,8-TCDD (less than one-millionth of a gram) is enough to kill an adult guinea pig. (Freese, 2012)
But the concerns do not end there. 2,4-dichlorophenol (2,4-DCP), a breakdown product of 2,4-D, is on the EPA’s toxics release inventory. According to Dow, exposure of just 1% of a worker’s body (an area the size of the palm of a hand) to molten 2,4-DCP may cause death. French scientists concluded that “following 2,4-D treatment, 2,4-D-tolerant plants may not be acceptable for human consumption” due to the breakdown of 2,4-D to 2,4-DCP, and the potential for further transformation of 2,4-DCP residues into highly toxic dioxins and furans in the body. (Freese, 2012)
At a Crossroads
Bill Freese, Science Policy Analyst for the Center for Food Safety, concludes, “American agriculture stands at a crossroads. One path involves ever more intensive use of pesticides, facilitated by genetic engineering, still bigger mega-farms, and further depopulation and impoverishment of rural America. This is the path of industrial agriculture.” Freese goes on to indict the pesticide-biotech solution, stating, “Dow’s 2,4-D-resistant crops are the epitome of this unsustainable approach, which sacrifices human and ecosystem health as well as rural communities for cheap food and short-term profits.”
Freese unequivocally states the alternative path to the future: “Organic farming rejects synthetic pesticides and genetic engineering, and utilizes non-toxic, sustainable methods to control pests (including weeds) and enrich the soil. Organic sales are growing by leaps and bounds as more and more people vote with their pocketbooks to support small farmers, rural communities, wholesome foods, and a healthy environment.”
Success is being demonstrated by other alternative farmers, as well. Many no-till farmers in the Midwest are focusing on crop rotations, cover crops, and soil health, thereby greatly reducing herbicide and fertilizer use. Integrated weed management works. The herbicide treadmill and the alternative IWM path are well documented and well-worn paths—but only one leads to long-term (sustainable) success.
Spread the Word
In addition to continuing to vote with our pocketbooks, those of us concerned about the environment, food, and sustainable farming can influence change by talking about this issue with friends, neighbors, colleagues, and local and national decision-makers. We can voice our concerns at this crossroads in agriculture. We can stop the escalation of chemical warfare that threatens our food system, public health, and the environment.
For more talking points about 2,4-D, see the MOSES website (mosesorganic.org) and click on Take Action under the Policy Work tab.
Audrey Alwell is the Communications Director for MOSES, and Managing Editor of the Organic Broadcaster.
Benbrook, C. (2012). Impacts of Genetically Engineered Crops on Pesticide Use in the United States: The First Sixteen Years. Environmental Sciences Europe 2012, 24:24. Accessed 6/2/14 at: http://www.enveurope.com/ content/24/1/24
Duffy, M. (2001). “Who benefits from biotechnology?” presentation of Dr. Michael Duffy, Iowa State University agricultural economist, to the American Seed Trade Association meeting, December 5-7, 2001, Chicago, IL.
Freese, B. (2012). Going Backwards: Dow’s 2,4-D-Resistant Crops and a More Toxic Future. Accessed 6/1/14 at: http://www.centerforfoodsafety.org/files/fsr_24-d.pdf
Heap, I. (2014) The International Survey of Herbicide Resistant Weeds. Online. Internet. Thursday, June 05, 2014 . Available www.weedscience.org. List of herbicide resistant biotypes in the USA available at http://www. weedscience.org/Summary/Country.aspx?CountryID=45
Mortensen, D.A., J. F. Egan, B.D. Maxwell, M.R. Ryan, R.G. Smith (2012). Navigating a Critical Juncture for Sustainable Weed Management. BioScience, Vol. 62, No. 1 (January 2012), pp. 75-84. Accessed 6/1/14 at: http://bioscience.oxfordjournals.org/content/62/1/75.full.pdf+html
PBI/Gordon Corporation. 2013. LV 400 2,4-D Weed Killer A Low Volatile Ester. Accessed 6/2/14 at: http://www.pbigordon.net/pdfs/LV400-SL.pdf
From the July | August 2014 Issue