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Public Policies, Research and the Economics of Herbicide Resistance Management

A workshop on Nov. 8, 2013, examined public policy implications related to  herbicide resistance management. The workshop, "Public- and Private-Sector Policy Implications of Research on the Economics of Herbicide Resistance Management," was a collaboration of USDA's Economic Research Service and Farm Foundation, NFP.

Academic and government economists and plant scientists are researching the causes and consequences of glyphosate resistance and the characteristics of weed best management practices that can delay resistance. This workshop was designed to continue an ongoing conversation between economists, plant scientists, producers, and industry and government representatives on the public-and private- sector policy implications of current research findings. This includes the tradeoffs associated with alternative programs that might help farmers, crop consultants, cooperative extension personnel, and the pest control industry manage herbicide resistance.

 CLICK HERE to review the speaker bios.

Nov. 8 Workshop Presentations
Mike Livingston, USDA Economic Research Service

Weed Resistance – How We Got Here and Where Are We Headed?
Harold Coble, USDA Office of Pest Management Policy
: Weed resistance to herbicides is not a new phenomenon. Resistance to the common herbicide 2,4-D was documented as far back as the 1950s. However, resistance has hit the front page since the discovery of resistance to glyphosate, the most widely used herbicide worldwide. The development of glyphosate tolerant crops, particularly soybean, cotton and corn, led to widespread use of a single weed control tool–glyphosate–on many millions of acres of cropland, thus reducing the diversity of weed management practices used by growers of those crops. Glyphosate did not cause weed resistance, but the reduced diversity of management practices allowed the selection of those species with resistance characteristics to become dominant in the population. What led to the problem was a mindset that weed control could be accomplished with a single tactic and that tactic would always be successful. Unfortunately, that mindset still appears to be prevalent, and as Einstein is credited with stating “you cannot solve a problem with the same mindset that created it”. Thus, solving weed resistance will require a mindset change on the part of decision makers, or, in my opinion, agriculture is headed for a massive train wreck.

Common Pool Resource Issues in Managing Herbicide Resistant Weeds
David Ervin, Portland State University
Abstract: Controlling herbicide resistance (HR) will require the integration of economics and social science with the biophysical and technological aspects of this growing problem. The existence of mobile herbicide resistance and/or herbicide tolerance traits adds complexity as genetic susceptibility to the herbicide is a resource open to all farmers impacting the weed population. Weed scientists have recognized that the “tragedy of the commons” may appear when herbicide resistance is mobile across farms. However, the private and public institutions that can influence individual and group decisions about HR have received sparse analysis. When such conditions prevail, reliance on voluntary education, technical assistance and other incentives aimed at changing individual grower behavior likely will fail to stem the advance of HR. The design principles from Elinor Ostrom’s pioneering research on CPR can be used to inform the design and implementation of such approaches, as well as lessons from CPR approaches outside of HR. (This presentation is based partly on a paper co-authored with Ray Jussaume of Michigan State University, entitled “Integrating Social Science into Managing Herbicide Resistant Weeds and Associated Environmental Impacts,” that is under review and revision in Weed Science.)

Herbicide Resistant Weeds: How Did We Get Here and What Do We Do Now?
George Frisvold, University of Arizona
Abstract: The pervasive adoption of herbicide resistant (HR) crop varieties since there mid-1990s introduction led to a dramatic reduction in the diversity of weed control tactics in U.S. agriculture and the predictable evolution of HR weeds. While most growers have adopted many resistance management practices most of the time, this has been insufficient to delay resistance. This paper examines the role of economics in explaining both farm-level incentives to manage weed resistance and the types of public policies adopted (and not adopted) for resistance management. Rather than focus solely on farm-level decisions, the analysis considers economic incentives for the many different public and private agents influencing weed control practices and technologies. It concludes by identifying key data needs and unanswered research questions that could improve design of resistance management policies.

Spread of Herbicide Resistance in Row Crops and Thoughts on the Potential for Future Success of Integrated Weed Management Practices
Vince Davis, University of Wisconsin-Madison
Abstract: Herbicide-resistant weeds are a tremendous threat to corn and soybean producers as weeds routinely cause the greatest economic loss when compared to all other pests. Despite numerous weed control options available to producers, monetary losses due to weeds in 2010 were estimated to be over 2.6 billion dollars in the U.S. and more than 44 million in Wisconsin alone when losses are derived from expected weed-free yields minus actual yields. These losses would be exponentially higher if comparisons were made between weed-free yield and yield of crops under full competition with weeds (i.e. having very limited weed control tactics implemented), or alternatively under situations where implemented weed control tactics were highly ineffective (e.g. herbicide control failure). The second scenario is how herbicide-resistant weeds have and will continue to vastly inflate the total losses of agriculture production. Following this statement would typically be a statement in the tone of a plea such as “adoption of integrated weed management (IWM) practices must be implemented by growers to off-set these detrimental effects”. It is true IWM practices must be implemented to a greater degree than has been in the past. But, more importantly than the need to implement, or re-implement, IWM tactics is the need for the discovery of new and improved IWM tactics to implement, because ‘traditional’ IWM tactics are not adequate to off-set concerns of herbicide resistance, protect the agricultural landscape from a return to intensive tillage and soil erosion concerns, improve sustainability for farms, and promote food security. If discovery and investment on new IWM tactics and improved cropping system designs do not happen quickly, it seems apparent that herbicide resistance concerns have us on the forefront of major crop production insecurity as the demise of effective herbicide ‘tools’ in major crops will also create problems in areas needed for the production of major and minor vegetable crops, as well as biofuel and alternative crops.

EPA’s Current Role and Planned Efforts to Contribute to Pesticide Resistance Management in Agriculture
Bill Chism, EPA Office of Pesticide Programs
Abstract: The EPA’s Office of Pesticide Programs has been working with agricultural pesticide registrants, pesticide users and the general public to identify ways to better manage the development of resistance to pesticides in pest populations. EPA believes that reducing the development of pesticide resistance will result in more effective long-term pest control strategies since crop producers can reduce unnecessary or ineffective pesticide applications to manage pests. Effective resistance management strategies should also lengthen the useful life of existing registered pesticides and reduce costs to farmers. Some of the Agency’s ongoing resistance management efforts include: (1) Updating the existing Pesticide Registration Notice (PRN) on resistance management labeling to emphasize mode of action and resistance management guidance on pesticide labels. (2) Establishing a publicly accessible webpage that provides information to stakeholders on Agency activities regarding managing pesticide resistance. (3) Continuing outreach on resistance management issues, including educational efforts, to engage stakeholder organizations such as the scientific societies (e.g., the Weed Science, Entomological and Phytopathological Societies), grower associations, pest control operator organizations, and pesticide manufacturer associations. (4) Coordinating the Agency's work with similar work being undertaken by the USDA on resistance management.

Impacts of Herbicide Resistant Weeds on Conservation
Norm Widman, USDA Natural Resources Conservation Service
Conservation tillage, to include no till and reduced/mulch tillage, has not only improved production efficiencies for agriculture, but has also been very instrumental in addressing many soil and water related resource concerns. Some of the current herbicide resistant weeds are now appearing on many of the fields that have been using no till and reduced/mulch tillage. One of the first inclinations of many producers to address herbicide resistant weeds is to revert to more tillage. More tillage will lead to more soil erosion via wind and water as well as other negative offsite effects such as reduced water quality. Great strides have been made by production agriculture to address soil erosion and water quality over the last few decades. USDA, industry, and producers need to take this opportunity to explore alternative production practices and crops to address herbicide resistance and continue our soil and water conservation efforts. We need to seek out alternatives that are socially, economically and environmentally sustainable.

Measuring Adoption Intensity of Weed Resistance Management Practices using Data Envelope Analysis with Principal Components
Paul Mitchell, University of Wisconsin-Madison
Abstract: We describe a new method to conveniently measure farmer adoption of best management practices (BMPs) and empirically illustrate the method using data on adoption of weed resistance management practices among U.S. corn, soybean and cotton farmers. Quantifying BMP adoption intensity can be used to compare farms and regions and to track changes in farmer practice adoption over time, as well as to document the impact of policies, outreach programs, and technology changes. Furthermore, regression analysis can use such a measure to identify the determinants of BMP adoption. Because of the relatively large number of practices and the correlations among them, a composite index that integrates and aggregates over all practices is useful. We use common-weight data envelope analysis (DEA) to develop a univariate measure of farmer adoption intensity for a set of interrelated BMPs. In addition, we use polychoric principal component analysis before applying DEA to remove correlation among variables measuring adoption of individual practices and to transform these categorical variables into continuous variables better suited to DEA. As an empirical illustration, we apply the method to data for adoption of weed resistance management practices among U.S. corn, soybean and cotton farmers. Results suggest that most growers adopt most of the practices, but that there is room for improvement, particularly among soybean farmers. We find a significant positive effect on adoption for educational attainment and the percentage of counties in a farmer’s crop reporting district reporting weed resistance. We also find that farmer concerns about human health and environmental effects when making herbicide choices impact their adoption of weed resistance management practices.

Valuation of Herbicide Resistant Soybeans and Evaluation of Incentives for Weed Resistance Management
Terrance M. Hurley (presenting), Paul D. Mitchell, George Frisvold, and Stephen Aultman
Abstract: Glyphosate resistant weeds have become a growing problem for soybean growers who rely on the Roundup Ready® (RR) weed management program. One strategy proposed to address glyphosate resistance is use of a residual herbicide with the RR program. Using national survey data, we estimate pecuniary and non-pecuniary benefits of the RR program to soybean growers and the potential for price rebates to increase grower use of residual herbicides. The estimated expected net benefit of the RR soybean program was $17.02 per RR acre. With 92% of the 75.7 million U.S. soybean acres planted with RR varieties in 2008, the estimated expected net benefit totaled $1.19 billion for U.S. soybean growers. A majority (54%) of surveyed soybean growers were concerned about weed resistance and planned to treat 30% of their RR acres with a residual herbicide. There was a significant positive association between weed resistance concerns and use of residual herbicides. This suggests extension programs aimed at raising grower awareness about resistance may encourage residual herbicide adoption. A $1/acre residual herbicide rebate was estimated to increase RR acres treated with a residual herbicide from 30% to 46% and reduced the share of growers applying no residual herbicides from 61% to 50%. Higher rebates (up to $4/acre) would have provided little additional residual herbicide use. These results are consistent with Monsanto’s decision to raise its residual herbicide rebates from $3/acre in 2011 to $10/acre in 2012.

The Economics of Glyphosate Resistance Management
Mike Livingston, USDA Economic Research Service
Abstract: Glyphosate resistance is currently documented in 14 weed species in the United States, raising concerns about their economic impact and how to delay the expansion of glyphosate resistant (GR) weeds into new cropland. Analysis of 2010 survey data suggests that U.S. corn producers had observed GR weed infestations on almost six percent of planted acres and experienced lower yields as a result. Because profit losses are not statistically significant, however, the analysis suggests that GR weeds have not had much of an aggregate economic impact in cornfields to date. At least one herbicide other than glyphosate was used on 85% of planted corn acres; however, glyphosate was applied with no other herbicide–a practice believed to contribute to resistance–on 15% of planted acres, most likely because weed infestations were relatively minor on those acres. Farmers who relied solely on glyphosate spent less on herbicides and had higher yields than other farmers, on average, suggesting an important challenge facing efforts to promote the use of different herbicides. Simulation model analysis suggests that optimal herbicide applications can reduce the rate of glyphosate resistance by reducing reliance on glyphosate and by combining glyphosate with other herbicides when it is used. Furthermore, economic returns are always higher when using optimal herbicide applications after between two to three years of consecutive use. Coordinating resistance management efforts across farms is shown to increase the economic returns received by crop producers, and the economic tradeoffs of alternative regulatory and voluntary approaches are examined.

Panel Discussion
Panelists included the presenters—Bill Chism, Harold Coble, Vince Davis, David Ervin, George Frisvold, Mike Livingston, Paul Mitchell and Norm Widman—as well as Les Glasgow of Syngenta and John Soteres of Monsanto, who are both involved with the Global Herbicide Resistance Action Committee.

Closing Remarks
Mike Livingston, USDA Economic Research Service





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