Fingers can be pointed in multiple directions is assigning blame for how we ended up in this struggle with resistant weeds and increasing pesticide use.
First, the pesticide-seed-biotech industry failed to assure that herbicide resistance management was a core and mandatory component of herbicide product-stewardship plans.
Even before the first field was planted to “Roundup Ready” crops, many weed scientists had warned farmers, the industry, and the EPA that the technology would almost certainly accelerate the emergence of resistant weeds.
They were proven right after about five years of use, when the first glyphosate-resistant weed triggered by-HR technology was discovered in Delaware in 2001.
When the first glyphosate herbicide product labels covering applications to GE-HR Roundup Ready crops were drafted and submitted to EPA in the early 1990s, Monsanto and other herbicide manufacturers chose not to impose mandatory resistance management provisions.
Even after multiple weeds had developed resistance and had become a major problem in the Southeast on cotton farms (circa 2005), many industry leaders and scientists still argued that there was nothing different about GE-HR crops relative to the risk of resistance, and that resistance to herbicides has been a well-known, routine management challenge for all herbicides for decades.
Syngenta was one of the companies developing and selling GE-HR crops, and glyphosate herbicides in the early 2000’s, the time period when several economically damaging, glyphosate-resistant weeds emerged and started spreading rapidly.
In an effort to develop consensus within the industry on both the need for, and nature of, resistance-management interventions, the company developed a detailed glyphosate resistance-management plan.
Syngenta was well along in the process of implementing the plan across its glyphosate product labels when objections from other companies and industry leaders, and especially Monsanto, ended the effort to put the plan in place across the industry.
Syngenta backed away from adding the core provisions to its glyphosate product labels, because they feared that doing so would simply transfer market share to other manufacturers of glyphosate-based herbicides.
Since that failed effort led by Syngenta, there has been no significant, industry-driven steps to prevent the emergence and spread of herbicide-resistant weeds.
Even worse, industry weed management technology investments over the last decade have almost exclusively pursued the development of new GE-HR, and associated herbicide products. This doubling-down on GE-HR technology is bound to accelerate the emergence and spread of weeds that are resistant to several, and eventually all herbicide families of chemistry.
This almost inconceivable outcome — the endgame in the evolution of super-weeds — has actually happened on many cotton farmers in the Southeast, where there are no longer any viable and affordable, herbicide-based weed management options
The second institutional failure was the decision by the EPA in the early 1990s to let marketplace forces sort out the winners and losers associated with the emergence and spread of resistant weeds.
The EPA has defended this key strategic decision by arguing that federal pesticide law does not grant the agency any role, or authority, to assess the risk of resistance, nor in crafting proactive steps to prevent it.
Fortunately, the EPA has taken some baby steps in the last few years to emphasis the need for more attention to, and adoption of core herbicide-resistance management practices.
The agency has begun work that will eventually lead to an update of a 2001 “Pesticide Registration (PR) Notice” on pesticide resistance management. As part of this effort, the EPA has circulated for public comment a May 2016 draft PR Notice on the subject “Guidance for Herbicide-Resistance Management, Labeling, Education, Training, and Stewardship.”
It sets forth potential new requirements that the EPA may someday impose on registrants regarding how herbicide-resistance management practices should be addressed in herbicide product labels. In explaining why the Agency is preparing a separate PR notice on herbicides, the EPA states:
“The Agency is focusing on the more holistic guidance for herbicides, first because they are the most widely used agricultural chemicals, no new herbicide mechanism of action has been developed in last 30 years, and herbicide-resistant weeds are rapidly increasing.”
The draft herbicide resistance PR notice proposes an effective framework for dividing the current, 28 herbicide “Mechanisms of Action” (MOAs) into three levels of concern (low, moderate, high). It also identifies 11 “elements” that can be drawn upon in reducing the risk of resistance.
The elements span label changes, education and training, and product stewardship strategies. In general, manufacturers of herbicides in the higher-risk categories would be encouraged, and perhaps required, to incorporate more or most of the 11 elements in their herbicide product labels.
Still, while each of the 11 elements can play a supportive role in preventing resistance or slowing its spread, they fall far short of what will be required to markedly alter the trajectory of resistant weeds.
For example and unlike Syngenta’s proposed resistance management plan from a decade earlier, the EPA elements do not include any restrictions on how often, or how many years in a row, a given field can be sprayed with a high-risk-for-resistance herbicide like glyphosate.
There is wide agreement in the academic weed science community that limiting use of high-risk herbicides to once or twice every three years on any given field is the surest way to markedly slow the spread of resistant weeds. In fact, without such a binding limitation on the frequency of use, the adoption of all 11 elements in EPA’s draft PR notice will be too little, too late.
Despite its soft touch, the EPA’s draft herbicide resistance PR Notice starts a process that might evolve to encompass a meaningful set of industry-wide requirements that will collectively make a real difference. Time will tell.