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2,4-D to Lead Wave of Pesticides Coming off Bench

  • By Jenny Hopkinson
    July 8, 2014

For related articles and information, please visit OCA's Genetic Engineering page and our Millions Against Monsanto page.

An ingredient in Agent Orange - 2,4-D - could soon see its use triple as a pesticide on American fields despite concerns that it could be linked to developmental and neurological health problems.

But it's not the only pesticide looking to play a bigger role in crop production. Approval is also being sought for genetically modified crops that could increase the usage of dicamba, HPPD and glufosinate - all weed-killing chemicals that had largely been pushed aside in favor of what has until recently been the pesticide industry's superstar: glyphosate.

Why the shift? The industry blames the movement in large part on a misplaced bet on biotechnology.

"We thought that biotechnology was going to be a solution and a long-term solution that would replace chemistry, so as a result people stopped investing in chemistry," Paul Schickler, president of DuPont Pioneer, told POLITICO Pro in a recent interview. As a result, the agriculture industry finds itself in a place with growing resistance by weeds to glyphosate and other pesticides, but no new and safer chemicals coming down the pipeline for at least another decade or two.

The near-term solution for managing the problem involves pulling other pesticides back into the spotlight.

Comments to EPA were due June 30 on Dow AgroSciences' proposed mix of 2,4-D and glyphosate for use on its new "ENLIST" corn and soybeans, crops that are genetically modified to be resistant to the herbicides.

The chemical 2,4-D has been used as a pesticide for more than 60 years, has been heavily studied and is approved for use by EPA and more than 70 other countries. It is among the top five most commonly used agricultural herbicides. About 30 million pounds of it are sprayed annually on U.S. fields and lawns, according to 2007 data from EPA released in 2011.

2,4-D has a bad reputation dating back to its use as a defoliant during the Vietnam War. Agent Orange - of which 2,4-D was one of two main ingredients - has been linked to increased rates of cancer, nerve and other health problems in veterans.

2,4-D was not the most problematic ingredient contained in Agent Orange. That was 2,4,5-T, another chemical that was used as a pesticide until EPA banned it in early 1979.         

Regardless, consumer advocacy groups continue to use the Vietnam War-era moniker to attack Dow's new 2,4-D uses. The Center for Food Safety, in January, launched a campaign against Dow's ENLIST products, dubbing them "Agent Orange crops," and gathered roughly 100,000 signatures to urge USDA rejection.

CFS also asserts that 2,4-D has its own problems. In its 17-page comment letter filed June 30 - among more than 1,000 comments received by EPA - the group says the agency's risk assessment "ignored or summarily dismissed key epidemiology studies linking 2,4-D exposure to cancer and Parkinson's disease, among other conditions   These assessment failures make it imperative that EPA reject the proposed registration, and postpone any decision until adequate analysis is undertaken in the context of EPA's 2,4-D registration review."

To further the case, the Environmental Working Group, another advocacy group, last week released analysis noting how there are 5,609 schools within 200 feet of fields that could be planted with the crops genetically modified for 2,4-D tolerance.

"When it comes to dousing crops with noxious chemicals, EPA focused on buffer zones for plants, not people  " EWG said in a statement announcing the analysis. "In its assessment, the EPA called for a 200-foot buffer zone to protect non-weed plants from the product but glosses over the health risks to children."

Dow stands by the safety of its new pesticide combination, saying ENLIST Duo, and 2,4-D more broadly, have been thoroughly studied and approved for use by EPA and other regulatory bodies around the world. The company has reformulated the chemical to form bigger droplets that inhibit drift by the pesticide, a main concern over its use in the past, Damon Palmer, Dow's U.S commercial lead for ENLIST, told POLITICO Pro.

Safety concerns are "a sock I can turn right-side out," said Garry Hamlin, a spokesman for Dow. "When you consider a product that is as widely regulated as 2,4-D is and has had so much scrutiny you have to wonder how if the database is not sufficient" to show it is safe, the chemical has remained in use since it was first approved by U.S. regulators in 1947.

"Much of the criticism that we are finding being applied to 2,4-D tolerant crops actually applies more broadly to GMOs and to pesticides and is being vocalized by people who have a very different view of agriculture," Hamlin said.

And something else the company says about 2,4-D: It works.

"We really do have very few 2,4-D resistant weeds out there," said Mark Peterson, a Dow research project manager. "We anticipate, if used properly, that 2,4-D is going to be a valuable part of weed control for many years to come."

But 2,4-D is just the first of several back-benched herbicide chemicals that soon could get more playing time. Monsanto and Syngenta are also seeking regulatory approval from USDA and EPA for crops that are resistant to proprietary blends of such chemicals as dicamba, glufosinate and HPPD - all of which have drawn the scrutiny of environmental and public health advocates.

Dicamba has been "tentatively linked to increased incidence of colon, lung and immune system cancers in pesticide applicators," the Center for Food Safety says.

The trend to bring back older pesticides stems from the industry's long standing reliance on glyphosate. The chemical, which was first developed in the 1970s, is effective on roughly 300 plants and grasses. It is inexpensive to produce and has relatively low toxicity in many animals and humans.

The herbicide was so effective that, like many other chemicals, it could also damage the crops it was intended to protect. As a result, in the 1990s, Monsanto started releasing glyphosate-resistant corn, soy and cotton under its Roundup Ready brand, and farmers flocked to the technology. Other pesticide manufacturers quickly followed suit when Monsanto's patent on glyphosate expired in 2000, taking glyphosate usage to what it is today.

U.S. farmers sprayed 185 millions pounds on their fields in 2007, more than double what was used in 2001, according to EPA data.

However, along with the high use of glyphosate has come weed resistance. Roughly a dozen weeds across 70 million acres of U.S. farm land are now tolerant to the chemical, according to Dow.

As the pesticide industry focused on developing new strains of glyphosate-resistant crops and other uses of biotechnology, it stopped investing in the search for a new pesticide, DuPont's Schickler explained. Pesticide manufacturers are now realizing they should always have a "new and better, safer, less toxic chemical in [their] pipeline."

The problem is, Schickler and others said, it's going to be at least another decade, if not much longer, until that next new thing comes along.

"I think every company out there would love to come up with a new herbicide 'mode of action,'" or way of killing weeds, Dow's Peterson said. "The issue is they aren't that easy to come by anymore. A lot of the low-hanging fruit   have really been picked."

As a result, pesticide companies are turning to mixtures of herbicides and sometimes reformulations to tide them over until that new chemical is developed.

"What this boils down to is that weeds are one of the most persistent threats to our food supply," Dow's Peterson said. Weeds are constantly adapting, not just to pesticides, but also non-chemical management efforts like tillage and cover crops, and it is going to take a combination of biotechnology, pesticides and other management practices to control them going forward.

But it's a plan that causes health and environmental advocates, and much of the public at large to fret. By fighting herbicide resistance with more herbicides, USDA and EPA are perpetuating a "chemical treadmill," said Scott Faber, executive vice president of the Environmental Working Group. Their approval could cause a huge increase in the use of legacy pesticides, which Faber said have been linked to health problems.

"We are at a tipping point," Faber said. "This is a point where USDA, EPA and our agricultural leaders ought to be saying, 'We are on the wrong road. The strategy we have adopted for 20 years is failing'  To simply do more of the same, it meets Einstein's definition of insanity."

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