(Beyond Pesticides, November 8, 2012) In response to an emergency exemption granted by the U.S. Environmental Protection Agency (EPA) to allow the unregistered use of the herbicide fluridone on cotton in order to control glyphosate-resistant weeds, the agency announced in the Federal Register Monday that it is establishing time-limited tolerances for residues of the chemical on food. Because resistance to herbicides in genetically engineered crops is predictable and expected, Beyond Pesticides has challenged EPA’s use of the emergency exemption provision of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), Section 18, in this and other similar cases.
According to EPA, of the glyphosate-resistant weeds, Palmer amaranth has become the most severe weed problem in Arkansas cotton production. It can reduce yields of cotton by more than 50 percent if there is a density of at least 10 of these weeds per row. Over 95% of Arkansas cotton and 80% of soybeans is genetically engineered (GE) to be glyphosate tolerant. Because glyphosate is the base herbicide used for weed control in this region, economic loss is expected on nearly 25% of acres grown. Over-reliance on herbicide-tolerant GE crops have caused the spread of resistant weeds that force farmers on the pesticide treadmill to increase herbicide application rates, spray more often, and add new herbicides that work through alternate modes of action into their spray programs.
In August 2011, a series of studies found that at least 21 different species of weeds are resistant to the herbicide glyphosate, commonly sold as Roundup and used across thousands of acres of ‚ÄúRoundUp Ready‚ÄĚ GE crops. Over-application by farmers on glyphosate to solve all of their weed problems has led to the proliferation of so-called ‚Äúsuper weeds,‚ÄĚ which have evolved to survive the treatments through repeated exposure. The spread of resistance is what has led farmers to increasingly rely on more toxic alternative mixtures. There has also been an increased push by chemical companies to engineer seed varieties that are tolerant to multiple herbicide treatments, such as dicamba, glyphosate and 2,4-D, or glyphosate and acetochlor. Dow AgroSciences and Bayer CropScience recently petitioned the USDA to deregulate 2,4-D GE corn and soybeans in order for 2,4-D and other herbicides to be used to tackle weeds resistant to glyphosate.
This is the first time EPA has granted an emergency exemption request for the use of fluridone on cotton. The exemptions will expire in 2014 unless evidence is brought to EPA showing the chemical to be unsafe. Through its Section 18, or emergency exemption program, EPA allows the use of pesticides that are not registered for a particular crop, or in some cases not registered for use at all, but making progress toward registration. As a result of this use pattern, EPA sets tolerances for affected crops that are time-limited, usually for the season in which they are allowed. As a result, the database notes that these pesticides have an expiration date that is often renewed. The Section 18 emergency exemption loophole has been used in the past to skirt pesticide regulations meant to ensure health and safety and has resulted in the widespread application of unreviewed, and often unnecessary hazardous substances. In some cases, exemptions have been granted each season, challenging the concept that this is an urgent, non-routine situation as ‚Äėemergency‚Äô is defined under Section 18. Reoccurring problems like weed resistance to herbicides should be a wake-up call for farmers and EPA to reevaluate and implement alternative biological and cultural management practices for the long-term prevention of diseases and end the reliance on the ‚Äúchemical fix‚ÄĚ that will exacerbate the problem when pest resistance to the chemical inevitably occurs.
Fluridone is an aquatic herbicide used to control large aquatic plants. It is currently registered for residential use on ponds and is used for the control of hydrilla and Eurasian milfoil. The registration review process for fluridone began in 2009. The most recent ecological risk assessment was done in 1991, however no assessment has been completed for endangered species, and ecological data was called in as part of the review process. A human health risk assessment was completed in 2004. EPA estimated aggregate exposure and risk from dietary exposure and exposures from swimming in treated water and the risks were considered ‚Äúbelow levels of concern.‚ÄĚ Most fluridone products have not been assessed for occupational exposures but EPA believes application exposure is negligible and does not anticipate conducting a post-application assessment. Final registration review is expected in 2015.
Although the mechanism of action of fluridone in plants is understood, the mechanism of action of fluridone in mammals is not well characterized. Fluridone is rapidly absorbed, metabolized, and excreted by mammals. At sufficiently high doses, fluridone is associated primarily with changes in the liver, reduced body weight, and reduced food consumption. Fluridone does not appear to be carcinogenic, based on standard life-time toxicity studies in rats and mice. Similarly, there is little indication that fluridone will cause specific neurotoxic effects or impairment of immune or endocrine function.
Fluridone has two degradates of concern: N-methyl formamide (NMF) and 3-trifluoromethyl benzois acid. Ecological data has been called in for these as part of the registration review. There is some evidence that its major degradate, NMF, causes birth defects. In rats, a significant increase in the incidence of malformations including cephalocele and sternoschisis was observed in fetuses exposed to high doses of NMF. However, due to current limited use, NMF has only been detected in the lab and not following actual fluridone field treatments.
The hope that additional herbicide options like fluridone will stem the tide of herbicide-resistant weeds is like feeding fuel to the fire in hopes it will go out. This process ensures that farmers are stuck on a pesticide treadmill which constantly demands greater amounts of synthetic inputs, including GE seeds, and rewards chemical suppliers at the expense of farm profitability and the environment. Sustainable, integrated pest management strategies, including organic practices, and not chemical-intensive solutions, are the appropriate solutions at this time. Organic agriculture is an ecologically-based management system that prioritizes cultural, biological, and mechanical production practices, and natural inputs. By strengthening on-farm resources, such as soil fertility, pasture and biodiversity, organic farmers can minimize and even avoid the production challenges that most genetically engineered organisms have been falsely-marketed as solving.
Take Action: Under section 408(g) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, any person may file an objection to any aspect of this regulation and may also request a hearing on those objections. Public comment on this final rule will be accepted until January 7, 2013. Comments may be submitted to the docket number EPA-HQ-OPP-2012-0756, at www.regulations.gov.
Source: Federal Register Notice
All unattributed positions and opinions in this piece are those of Beyond Pesticides.