Genetically Modified Crops

The USDA’s Animal and Plant Health Inspection Service (APHIS) has released a Draft Environmental Impact Statement associated with its deregulation of a new generation of genetically modified herbicide-resistant crops.   While many in the agricultural industry hail this as a much-needed step in the development of new weed-control technologies, critics worry that it will accelerate an “herbicide treadmill” at the cost of more sustainable management strategies.

As a bit of background, the development of the first generation of genetically modified (GM) herbicide-resistant crops revolutionized agricultural weed management in the mid 1990s.  Prior to this development, weed management required significant skill and knowledge.  Farmers had to not only carefully manage the timing of various herbicide applications, but also integrate other nonchemical control practices.  Herbicide-resistant crops, by contrast, were effective and easy to use.

During the initial phase of development, a variety of GM options came to market, but Monsanto’s “RoundupReady” varieties (which are resistant to a broad-spectrum herbicide known as “glyphosate”) quickly became dominant.   By 2008, 63% of corn fields and 92% of soybean fields in the US were being planted with RoundupReady seeds.  The outcome of this single-track approach to weed management has been a dramatic increase in the number of weed species that are resistant to the herbicide glyphosate.

In response to the evolution of these “super weeds,” Congress has held hearings to assess whether additional government oversight is needed to address the problem.  The response of the seed and agrichemical industries, by contrast, has been to develop new GM seeds that are resistant to other broad-spectrum herbicides for which weeds have not yet developed resistance.  The result of these efforts include the line of seeds by Dow AgroSciences that are currently under review by APHIS (which are resistant to an herbicide known as 2,4-D), as well as a new line of seeds by Monsanto (which are resistant to a herbicide known as dicamba), for which APHIS will be preparing an EIS. The deregulation of this new generation of GM crops gives rise to a variety of concerns.

The most significant concern is that the availability of these new GM crops will cause a dramatic increase in the use of 2,4-D and dicamba, which could not only hasten the evolution of weeds resistant to these chemicals, but also have negative consequences for environmental quality.  On this point, it is important to highlight that the use of these next-generation crops will likely not result in the substitution of herbicides in use, but rather the addition of new herbicides to current use patterns.  The reason for this is that the new Dow seeds are resistant to both glyphosate and 2,4-D, and the Monsanto seeds are resistant to both glyphosate and dicamba.  The companies are advocating herbicide programs that add the new herbicide (2,4-D or dicamba) to the current rates of glyphosate application.

In addition, it is unclear whether our current regulatory approach to GM crops is sufficient to adequately evaluate their risks, as it derives from a patchwork of laws designed for other purposes.  For example, while the USDA’s APHIS is responsible for regulating, managing and controlling “plant pests,” the EPA is responsible for regulating the sale, distribution, and use of pesticides.  While this approach is known as the “Coordinated Framework for the Regulation of Biotechnology,” the analysis of the various risks is not in fact coordinated.   If APHIS determines that a GM plant does not pose a “plant pest risk” to agricultural crops or other plants or plant products, it must then move forward with deregulation, which it is now doing.  The EPA is concurrently conducting a separate analysis of the impact of expanded use of 2,4-D, which it will release in the coming months.   One need not think that there is anything inherently risky about GM crops to think that a more integrated risk analysis would be appropriate.

A final concern is that the availability of these GM crops will contribute to the continued neglect of integrated weed management strategies, as well as public research in this domain, which could be necessary for long-term sustainable development.

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