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Down to Earth: Q&A with Pesticide Policy Expert Charles Benbrook

Pesticide policy expert Charles Benbrook explains how genetically engineered crops have spawned the creation of superweeds that destroy entire crop fields.

Length: 24 min 26 sec

Recorded: June 2011

[ Download MP3 ]

Earthjustice staffer Jessica Knoblauch speaks with Charles Benbrook, the chief scientist at The Organic Center.

Benbrook is a pesticide policy expert and weed resistance specialist who has worked on agricultural policy, science and regulatory issues in Washington, D.C. The use of genetically engineered crops has spawned the creation of so-called "superweeds," which force farmers to use more toxic herbicides for weed control.

Jessica Knoblauch: So you have a background in agricultural policy, science and regulatory issues. What made you decide to come to The Organic Center?

Charles Benbrook: The opportunity to work on a wide range of issues and areas of science that impact human health, especially nutrition, food science and food safety, which were areas I’ve always been very interested in but haven’t had much of a chance to work on. The portfolio of science that The Organic Center emphasizes is very broad and that really appeals to me. Our mission is to promote new science on the comparative benefits of organic food and farming, in particular in terms of human health, but secondarily in terms of the environment.

Jessica: Biotech companies like Monsanto have made a lot of claims about genetically engineered foods, including the claim that GE foods decrease pesticide use, but your research has found the exact opposite to be true. Can you tell me a little bit about that?

Charles: We’ve done four reports over the last ten years on this question. It’s true that the crops that have been genetically engineered to express the Bacillus thuringiensis toxin, BT corn and BT cotton, have reduced insecticide use. But all of the herbicide tolerant crops, which would include Roundup Ready corn, cotton and soybeans, have increased herbicide use by much, much more, hundreds of millions of pounds over what herbicide use would have been had these herbicide-tolerant varieties not been commercialized. So when the biotech industry makes the claim that today’s genetically engineered crops have reduced and are reducing pesticide use, they’re factually wrong when you base the comparison on the pounds of all pesticides applied. So the relatively modest decrease in insecticides is more than made up by the huge increase in herbicides.

Jessica: So how did this increase come about?

Charles: When farmers planted the first Roundup Ready crops in 1996 on just a few million acres, commercial adoption of Roundup Ready soybeans in particular and Roundup Ready cotton was very fast. As a result, weeds and soybean fields planted to GM varieties were being exposed to only one herbicide active ingredient, glyphosate, which is the active chemical in Roundup brand herbicide. Whenever farmers try to control weeds with a single chemical or single tactic, what they do is create selection pressure on the weed population so that weeds that are highly susceptible to the one chemical or the one tactic are completely controlled and don’t spread and don’t become any more of a problem. But those phenotypes of weed species that are less well controlled basically do a little bit better every year.

What happened in areas where farmers planted herbicide-tolerant crops year in and year out and tried to control weeds just with glyphosate for several years in a row is that they triggered shifts in the weed species in crop fields favoring those that are less well-controlled and ultimately, they actually triggered the creation of genetically resistant weeds through routine mutations that just happen in weed populations as a normal course of events.

The first fully resistant weeds to Roundup started showing up around 2001 and 2002, but by about 2005 the problem really had started to take off, particularly in the Southeast. And now there are multiple glyphosate-resistant weeds that are spread all over the Southeast. These weeds are actually undermining the effectiveness of the Roundup Ready system as a whole. In the Southeast it is a technology in active decline. In a matter of a few more years it simply won’t be a commercially viable option.

Jessica: So is this something that scientists saw coming?

Charles: Absolutely. Years before the first herbicide-tolerant crop was planted in 1996, weed scientists, weed ecologists, agronomists, environmental groups, farmers, etc. had openly warned that this was a technology custom designed to promote the emergence of resistance. The reason people recognize this and spoke about it so forcefully even prior to commercial adoption is that when Monsanto genetically engineered soybeans and cotton to allow farmers to spray Roundup all during the season, not only did this technology provide an incentive for farmers to rely solely or nearly exclusively on glyphosate for weed control, it also made it possible for farmers to apply Roundup two, three, even four times in a production season, which is exactly what some farmers did.

In the first few years of commercial use, the Roundup Ready system just worked incredibly well. Many soybean and cotton farmers were able to achieve season-long weed control with only one application. In the Southeast in cotton country, even from the beginning it usually took two applications because it’s such a longer growing season and there are some late season weeds that can emerge and be a problem in cotton production, so most of the cotton farmers right from the beginning were making two applications of Roundup. But after three or four or five years the shifts in weed communities had gotten bad enough that farmers had to apply a second time, and some even a third time. And then also because some of the weeds just weren’t as sensitive to glyphosate, farmers had to begin adding a new family of herbicide chemistry into their herbicide program. This is really when we saw both the cost of weed control in the Roundup Ready system and the volume of herbicides applied start to really rise quickly. That’s been the story for almost a decade now and it’s been getting progressively worse every year.

Monsanto’s corporate policy has been one of denial, until about the last year. Starting about a year ago, Monsanto has finally acknowledged that the emergence of resistant weeds is a serious problem with the Roundup Ready system. They are quick to point out that weeds are resistant to other herbicides. They will try to argue that there’s nothing different about the degree of resistance that exists today to Roundup compared to other herbicides. But, in fact it is different because of the way that Roundup is used and the degree to which Roundup has become the sole pillar of weed management in so much of corn, soybean and cotton country.

And this is why we see crews of men in the Southeast going out into Roundup Ready cotton fields and soybean fields with hoes to try to manually remove the glyphosate resistant Palmer amaranth, and the glyphosate resistant marestail that’s such a serious problem in that part of the country. But the remarkable thing about Palmer amaranth is that it grows so vigorously in conventional production fields in the Southeast that have a lot of nitrogen fertilizer put on them and a lot of other nutrients, once they get established they can grow really fast and they can actually get stalks as big as a man’s wrist. In some badly infested fields, the stalks of the weeds are so tough that they actually break the cotton harvesting equipment.

Palmer amaranth. Glyphosate-resistant, this weed can quickly grow very large. In badly infested fields, it can break cotton harvesting equipment and must be removed by hand.

Jessica: Geez. And you’re talking about really heavy, expensive equipment, I’m assuming, right?

Charles: Absolutely. It’s really heavy, expensive equipment. And when you start breaking the cutter bars because they’re trying to chop what is akin to a small tree, that doesn’t bode well for the harvest outcome.

Jessica: So about a year ago Monsanto started admitting that this is a problem. What’s their solution?

Charles: Spray more. Their proposed solution is to produce genetically engineered crops resistant to multiple herbicides, so that farmers can spray three or four different herbicides at the same time in the hope that at least one of the modes of action will still work. It’s a strategy that’s comparable to pouring gasoline on a fire to put it out.

Jessica: And these other herbicides are going to be more toxic?

Charles: That depends. They certainly have to be toxic to the plants in order to work. It’s going to be more difficult for the biotech and seed industry to get government approval for herbicide-tolerant crops linked to high-risk herbicides. I’m incredulous that they appear to be on course to get Dicamba-tolerant crops approved. Dicamba is relatively toxic to humans. It’s been clearly linked to increased birth defects and reproductive problems in the Midwest. It’s going to harm people and the volume of Dicamba that’s going to be used in areas with bad resistant weed problems is going to dwarf the most intensive use ever of that product. And from an environmental point of view, this is not a relatively benign herbicide like glyphosate.

Jessica: That’s pretty scary stuff.

Years before the first herbicide-tolerant crop was planted in 1996, weed scientists, weed ecologists, agronomists, environmental groups, farmers, etc. had openly warned that this was a technology custom designed to promote the emergence of resistance.

Charles: Yeah, it is pretty scary.

Jessica: Well, in light of that, what’s the alternative? The biotech industry has claimed that we have to have these crops in order to feed a growing population, in order to reduce water consumption, to decrease pesticide use. What’s the alternative?

Charles: The alternative is to back away from herbicide-tolerant and BT transgenic crop cultivars and provide the farmers greater supplies of seeds that aren’t genetically engineered. Right now virtually the whole seed supply is genetically engineered so the farmers don’t have a choice. If new science showed that herbicide-tolerant crops were the cause of autism, for example, triggering an immediate ban on them, it couldn’t happen and it won’t happen because there wouldn’t be enough seed to plant more than 10 percent of the soybean crop. The American food system cannot drop from 150 million acres of corn and soybean down to 20 million in one year and still support the American diet. It can’t be done.

Jessica: So one of the things that I mentioned, GE crops are necessary to feed a growing population, that’s a common claim from the biotech industry. Do you believe that organic and conventional crops can fill that void? Or is that even an accurate statement from biotech companies?

Charles: First of all, the vast majority of genetically engineered crops around the world are grown to feed animals in feedlots and confinement systems with the meat and the milk and the poultry products then being fed to what would be regarded as the economic elite when you look at the world population as a whole. And the remaining, major GM crop is cotton, which people do not eat. It is factually inaccurate to make the claim that today’s GE crops are contributing substantially to meeting food needs among the food insecure because the food insecure are not eating Big Macs and pork chops and milk shakes on a daily basis. They are surviving on wheat, cassava, corn, rice and the occasional serving of fish or meat. So it’s a complete misnomer and inaccurate for the biotech industry to claim that today’s genetically engineered crops are making substantial contributions to meeting food security needs because they’re not. They’re simply not.

To combat glyphosate-resistant weeds, farmers are turning to toxic herbicides like Dicamba and 2,4-D. The latter will kill grapevines at levels undetectable in air. (Francesco Sgroi)

So I think it’s a very hollow argument. There has yet to be a genetically engineered variety that was engineered to increase yields. It’s just simply not true that any of these varieties have higher inherent or innate yield potential. They’re all pest management-related traits. The only way that any of today’s GE crops increase yield is if they help a farmer do a better job managing weeds or insects that were, in effect, reducing yields below what the genetics of the crop were capable of supporting.

But for the most part that’s not a major factor in the U.S. Farmers before the advent of GE plants were doing a pretty good job managing both weeds and insects. It was an uncommon thing for a farmer to lose substantial yield to either weeds or insects in production areas. Now sure, farmers were spraying other pesticides, no doubt about that, and also using other practices. But in general American farmers have done a quite good job managing these major pests both before the advent of GE crops and they continue to do so now. The emergence of resistant weeds to the Roundup Ready system is really a problem because the herbicide industry reduced their investments dramatically in new herbicide discovery and commercialization because of the huge market share that glyphosate had. And now as farmers are forced to turn away from glyphosate, they’re finding that there really aren’t a lot of new herbicide families of chemistry out there to deal with these resistant weeds. That’s why the industry is creating herbicide tolerant crops to 2,4-D and Dicamba, which are herbicides that have been around for 30-plus years.

Jessica: And are particularly toxic ones at that.

Charles: Yeah, they are at the upper end of the risk profile. There are three big risks that are going to go up as 2,4-D and Dicamba are sprayed more widely—birth defects and reproductive problems, not just in humans but in all mammals; damage to non-target vegetation; and, impacts on aquatic ecosystems. These are volatile herbicides, they drift, they will move with fog and with the wind, and they’re extremely toxic to a number of fruits and vegetables. 2,4-D will kill grape vines at levels not detectable in the air.

Jessica: Wow.

[Monsanto's] proposed solution is to produce genetically engineered crops resistant to multiple herbicides, so that farmers can spray three or four different herbicides at the same time in the hope that at least one of the modes of action will still work. It’s a strategy that’s comparable to pouring gasoline on a fire to put it out.

Charles: This has happened multiple times in Washington State. You can spray a wheat field with 2,4-D and five miles away, a cherry orchard or grape vineyard will be hammered. There will be a huge reduction in the crop, if the trees and vines are not killed. But there’s no way, or almost no way to pin it on the drifting herbicide because the herbicide does the damage at a level below which it can even be detected. So watch out for thousands of episodes of damage to grandma’s tomatoes and roses all through the Midwest, when farmers start spraying 2,4-D and Dicamba on to cotton and soybean fields, which is exactly what they’re going to do if USDA approves these new herbicide-tolerant technologies. There’s going to be hell to pay because of the spray drift and the volatilization of these products.

Many people are really worried about this. The third big risk impact will be aquatic resources. 2,4-D and Dicamba are very toxic to a number of aquatic organisms. No doubt they’ll have quite an impact on the aquatic food chain. How that will affect the ecology of stream and river ecosystems and reservoirs and lakes is anybody’s guess. But Dicamba and 2,4-D are many, many, many times more toxic and dangerous than glyphosate. People who think that we can spray 50 or 100 million pounds of those herbicides in the Midwest a year and not pay a price just aren’t paying attention.

Jessica: Has The Organic Center done studies on whether organic food is a viable alternative to putting more and more pesticides on these crops?

Charles: Certainly there’s enough organic corn, soybeans, tomatoes, grapes, apples and leafy greens being grown in the country to remove any serious doubt about whether it’s possible to grow these crops organically. Clearly it is possible. And it’s also pretty clear that experienced organic farmers, after they’ve gone through the transition and really restored vitality to their soils are going to harvest more biomass off of their farm than if the farmer managed the operation conventionally.

These [glyphosate-resistant] weeds are actually undermining the effectiveness of the Roundup Ready system as a whole. In the Southeast, it is a technology in active decline. In a matter of a few more years it simply won’t be a commercially viable option.

The reason that that’s an easy case to make, even though their corn or soybean or tomato yields might be somewhat lower, is that the organic farmer is going to be growing usually two crops a year off that land, there’s always going to be a cover crop, there’s always going to be something growing in the spring. So the land in an organic system produces for the full number of months when there’s adequate moisture and sunlight to support plant growth. Stretching the production season is an essential part of the organic system, because the organic farmer needs to grow biomass to improve soil health and leguminous crops to put nitrogen in the soil. Because of using the production season more fully, the organic farmer harvests more than one crop off the field, whether it’s some hay for animals for grazing or just green manure to put back in the soil, it’s still production that contributes to the organic farmer’s bottom line and contributes to the overall productivity of that farming system.

Jessica: So it sounds like a pretty self-sustaining system.

Charles: It is surely closer to a self-sustaining system than most conventional systems. If there were a level playing field in terms of infrastructure and policy supporting all types of farms across U.S. agriculture, there would be a lot more acres planted to non-GE varieties and grown either organically or using sustainable methods because they make farmers more money. But right now, the infrastructure and the policy framework for agriculture is supporting high-energy, high-input GE agriculture. Because of those investments and policy bias, energy-intensive, GE-based conventional systems are more profitable. But such systems are not more profitable because they are or more efficient or more productive.

Jessica: That’s all the questions I had. Thanks so much for your time, and I’ll be in touch soon.

The views and opinions expressed by guests on “Down to Earth” audio podcast series do not necessarily represent the opinion or position of Earthjustice, its board or funders.

Despite growing concerns of genetically engineered crops, government officials continue to rubber stamp their approval.
In early 2011, the USDA announced the approval of Monsanto's genetically engineered Roundup Ready alfalfa. Learn about Earthjustice's litigation challenging the USDA for failing to properly assess the environmental impacts of Monsanto’s GE Roundup Ready sugar beets and alfalfa: GMOs: Engineering an Environmental Disaster

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