Thursday, January 24, 2013

The Muddled Debate About Pesticide Use And GM Crops

Does the adoption of GM crops lead to more or less pesticide use?  This is a frequent topic of debate, but generally one that misses the point.  Both sides make the same erroneous assumption that all pesticide use is, by definition, a bad thing.  In fact, it depends on the particular pesticide in question, the reason it is being used, and the details of its application.  Most modern pesticides are extremely low in hazard to us or to the environment.  Both "sides" of the GM debate would do well to stop over-simplfying this issue.

What Biotech Can and Can't Do

In his recent speech expressing regret for his former role in the anti-GMO campaign, environmentalist Mark Lynas cited cases where biotech crops reduced the need for pesticide applications (e.g. Bt Cotton and Bt Maize).  The examples are quite positive from the farmer's point of view.  However, for crops with biotech insect resistance, pesticides remain an important and well regulated tool for farmers who still have to deal with many other pests for which there may never be a biotech solution.   The supporters of crop biotechnology need to maintain the perspective that biotech traits are simply one tool in the tool box.  There is no excuse for ignoring the science behind advances in pesticide risk management any more than for ignoring the science behind risk management for GM technology.

Putting "Increased Pesticide Use" Into a Global Perspective

Jason Mark recently posted a "rebuttal" to Lynas' speech on Earth Island Journal.  It relied on exactly the sort of "self referencing" sources that Lynas critiqued, but one argument struck me as sufficiently absurd to warrant a response:

"A peer-reviewed study published last year in Environmental Sciences Europe found that GM plantings in the United States led to a 7 percent increase in chemical spraying."

Seriously? A European publication expressing angst about an incremental change in US pesticide use on its major crops? Do they know about the intensive use of pesticides on crops in Europe? (see graph below).  Actually, it is the study by Chuck Benbrook of the Organic Center in the US which generates a seemingly large number until you consider that his model includes use on hundreds of millions of acres over 16 years).

Why do European farmers use so much pesticide?  The reason is simple: they have to deal with lots of pests!  As with farmers everywhere, those in Europe face insects, weeds, fungi, bacteria and viruses which, if uncontrolled, diminish the amount of food that they can produce.  They farm in a generally wetter climate, and so they need lots of fungicides.  Like any farmer, they use the highly regulated pesticide options available to them so that they can limit the damage from those pests.  If they didn't use those pesticides, they would be making inefficient use of their land and of other necessary inputs like fertilizers and fuel.  As it is, Europe imports a great deal of its food and feed (206 million metric tons for the top 20 commodities imported in 2010).  When European farmers use pesticides to be as productive as possible, they at least help to minimize that strain on the global food supply.

Putting "Increased Pesticide Use" Into Quantitative And Contextual Perspective

The 7% increase Environmental Sciences Europe cites as an offshoot of GM crops mainly involves a herbicide, glyphosate, which happens to have a benign profile in terms of toxicity to things other than plants.  The transition to glyphosate for "Roundup Ready"crops replaced the use of sulfonyl ureas, a class of herbicides which had extremely low use-rates.  Thus, the still modest glyphosate use rate of 22-44 ounces of product per acre represented a small increase in total "pounds on the ground." Ken Cook of the Environmental Working Group responded to Lynas with a post in which he describes these crops as being "slathered with chemicals."  The 44 ounce rate means that each liquid ounce is spread over an area of almost 1,000 square feet. The active ingredient is applied at less than 0.01 grams per square foot.  Somehow, that does not fit my mental image of "slathered."

The far more relevant point is that glyphosate tolerant crops represented a more practical alternative to mechanical tillage for weed control and enabled wider adoption of "no-till" farming.  That is a system which conserves soil moisture, prevents erosion, dramatically reduces nutrient and pesticide movement to streams and rivers, and reduces fuel use.  If biotechnology and herbicides can combine with sophisticated equipment to enable this sort of farming - all the better.

Bottom line, a biotechnology trait may decrease or increases the need for a pesticide.  There will also be many cases where the biotech trait has nothing to do with pesticide use.  There is no necessary good or bad linkage between these two categories of agricultural technology - both can serve to make crop production better.  Both are options that should be available to those who farm.

You are welcome to comment here and/or to write me at  My Twitter feed is @grapedoc

Sprayer image from North Carolina Crops


  1. This isn’t up to your usual standards Steve, especially when you take exception to “a European group expressing angst about a 7% increase in chemical spraying”. Following your link it turns out to be a US-based researcher reporting a 7% change in a European journal , which isn’t the same thing at all. But so what if it was a European group criticising US agriculture? Surely what matters is the quality of the critique, not the nationality of the critic?

    As you yourself point out, biotech advocates like to list reduced pesticide use as a key benefit of the technology, so if it turns out that actually pesticide use is not reduced that’s worth knowing. We can argue about how much it matters, but that’s another issue – so unless you have figures to the contrary, perhaps we can now agree that GM crops have not reduced pesticide use in the US?

    You also rightly point out that over time pests become resistant to pesticides of all kinds, including transgenic ones. But this isn’t something the biotech industry has been quick to admit – a lot of ignorant public discussion still seems to think that GM technology somehow puts an end to pest problems once and for all. How long do you think the advantages of transgenic Bt crops will last before the pests catch up? What kinds of seeds and pesticides do you think will be needed to replace them? And who will control that technology?

    The benignity of glyphosate’s profile is rather more controversial than you claim, but whatever the case why – other than our obvious threat to commercial monopolies – are biotech advocates so keen to decry those of us trying to figure out non-chemical pest control methods? Surely anyone with a bit of biological wisdom can see the advantages of hedging bets and adopting mixed strategies? Our methods may or may not be less efficient in terms of yields per acre, but are often more efficient in terms of yields per non-renewable input, which is also a relevant consideration. And if you want to talk about efficiency in the European food system, why do we ban pig swill, feed something like half of our cereals to livestock and throw a third of our food away? We could improve efficiency massively if we addressed those issues, but I don’t see much biotech industry lobbying on those fronts.

  2. Chris,
    You are right. It turns out to be the standard Benbrook study. I misread the description on the Earth Island piece. I've edited above. Actually; however, the study shows a smaller increase than it sounds because it is looking at many years over hundreds of millions of acres of use.

    As for US use on biotech crops it is a total mix of up and down and the up is not some big problem. Fungicide use in the US and in Europe goes up and down far more dramatically from year to year depending on how wet it is. Insecticide use in California dropped dramatically in (I believe) 2010 because it was unusually cool.

    As for biotech being slow to recognize the resistance issue - I remember sitting in a presentation to a biotech company well before the commercialization of the technology where a researcher was presenting models about how resistance would develop depending on the management practices adopted. The topic was widely discussed and anticipated. Bt crops have held up in most cases because of the refugia set aside. There are also multiple genes in use now. Growers have many options - no one "controls" this market.

    You are welcome to develop your non-chemical methods and no one, I mean no one, in the agricultural chemical space is worried about your "threat to commercial monopolies." Patents only grant a limited period of exclusivity, and even with them the agricultural chemicals market is extremely competitive. As for what Europe does with regard to food, I won't try to answer for you (it sounds like you are from there). Food waste is a huge issue, but to very different extents depending on the crop and the region. I've spent much of my career on those issues.

  3. Thanks for the clarifications. ‘A total mix of up and down’ sounds plausible – I’m sure we could unpick this some more, but I’m glad at least that I can now quote you on that the next time somebody tells me that GM crops require less pesticide.

    Yes, of course the industry has addressed resistance but it doesn’t exactly go out of its way to raise resistance as an issue in public/media debates. I’ve heard plenty of media discussions in which GM proponents talk about the technology as if it has some kind of magic pest-defeating power rather than accepting it’s just another tool in the box. Obviously refugia help, but probably not indefinitely – and especially not in situations where farmer practices are not easily controlled, as I imagine is the case among small cotton growers in India.

    I’d be interested to know what your definition of a competitive market is. Taking, say, the largest ten agro-chemical companies in the US, what’s their market share?

    You say we’re welcome to develop our non-chemical methods. But do you welcome the fact that we’re trying? And if not, on what biological or other grounds do you oppose our efforts? It wouldn’t surprise me if people in the agro-chemical space weren’t worried about us, because we’re pretty powerless compared to you...but then why do you spend so much time trying to rubbish what we’re doing, persecuting farmers for saving seed etc etc? Just guessing, but I think deep down the agribusiness world does worry, because it knows that farmers and their customers don’t really need it unless it can make them dependent upon it. On that note, it’s interesting that a speaker at the recent pro-GM Food Security 2012 conference in London admitted in relation to GM crops, “It may be that the things that are most profitable don’t necessarily contribute most to food security or sustainable food production”. Nicely put.

  4. Chris,
    I don't know what public/media debates you mean, but the way to know that the industry takes resistance seriously is to see what is actually done. Since the early 1980s all of these companies have been involved in cooperative international efforts to manage resistance to ag chemicals (FRAC - fungicide resistance action committee, IRAC, HRAC...). They have put resistance management rules in place for Bt crops. Will all farmers in all settings always do the best they could on resistance management? Not always - but industry, extension, grower organizations etc do what they can.

    In ag chem you have ~7 players who have the capacity and profit margins to spend the billions it takes to maintain a discovery program (BASF, Bayer, Syngenta, DuPont, Dow, Sumitomo, FMC and a few others). There are also many generic players who can't afford much if any discovery research, but which offer farmers off-patent materials (MANA, Arysta, Gowan and many others). There are also a great many biologicals/natural product companies. What this means is that farmers have many options for the control of pests and the prices for these products definitely has to represent a strong return on investment for the farmer.

    As for non-chemical methods - it isn't as if you are doing something so unique there. My PhD research was on how to use microclimate modification via pruning/trellising/leaf removal to reduce Botrytis infection of grape (non-chemical). At Mycogen I worked on biological controls and I still frequently consult with large and small companies on that topic. Plant breeding (conventional and now marker assisted) has been a huge, long-term investment by the industry. Probably the largest single non-chemical control has been the planting of crops in areas where the weather is less conducive for their pests (something the local movement is trying to undo). People in academia and in industry have worked on classical biological control (insect predators/parasites...) for decades. Crop rotation is a "non-chemical" control method used for centuries. Mating disruption is done with a chemical (insect hormone), but would sort of fall in the non-chemical side, and people in my industry have been working on that for decades. To me and to most people I work with, these are all just part of the total tool box and we are quite supportive of them. Look at what I said about the biological control for aflatoxin with atoxigenic strains. That is a technology I've been excited about since the early 90s.

    The folks in ag technology don't "rubbish" what you are doing, nor do they "persecute farmers for saving seed." The only reason I speak out about the myths associated with organic is that they make consumers believe things that simply are not true and I think truth matters. I also dislike the way that many organic advocates demonize conventional farmers with completely distorted information, a small sample being the "slathered" terminology above. I consider groups like the EWG to be highly destructive to the public good and believe they should be called out for it.

    1. As someone who has left the "organic" movement for more independent climes, I can say that their constant din of imagined injury combined with seething anger is a tone I don't miss:

  5. Thanks for your comments again Steve. Actually, I agree with you that there's an unfortunate tendency to demonise conventional farmers, though I'd say that it usually comes from urban food activists and not organic farmers. I also agree with you that there's nothing new about non-chemical methods - though you might not think so when you consider the use of the term 'conventional' and the fact that you have to be certified to practice organic farming and not the other way round. On other issues - seed saving, market competition, GM resistance debates etc - I'd beg to differ. No doubt everybody would wish to claim that 'truth matters' to them, but truth can be a surprisingly elusive target when we try to track it down, and our claims to be revealing it usually involve a whole bunch of implicit normative presuppositions - which is probably why 'Anonymous' sees imagined injury and seething anger amongst organic advocates, whereas I tend to see short-sighted, self-serving, arrogant condescension among agribusiness advocates. I'd say 'rubbishing' pretty much captures what the likes of Dennis Avery, Robert Paarlberg, Matt Ridley and Mark Lynas have to say about organic farming. And given its minute presence globally, I'd have thought that anyone with any kind of biological wisdom would welcome it as a bet-hedging strategy. Still, I find your posts informative, even though I share few of your implicit assumptions.

  6. Chris,
    I agree with you that the demonization of conventional farmers comes from urban food movement types for the most part, an I have great respect for organic farmers because of several that I have known for decades. I actually feel that the organic movement has been hijacked by an unholy alliance of marketers and anti-business activists and that its greatest insight and contribution (understanding the positive need to build soil quality) has been subjugated so that its "brand" is now defined almost entirely by what it is not: synthetics, GMO, irradiation...

    Of the agribusiness advocates you list, I know Rob Paarlberg the best, and I think if you met him you would understand where he is coming from. As a long-term expert on the economics and politics of food for the developing world (particularly Africa), what he has articulated is the ethical problem of rich world sensitivities being transmitted to policy and regulatory processes that have seriously compromised progress in allowing poor, small-holder farmers from getting the tools they need to be more productive. He has also seen how governments around the world have been reducing their long-term investment in agricultural research, particularly for the developing world - often because of political leadership that has been influenced by the idea that only organic is pure and sustainable and should be what poor people do as well.

    Anyway, thanks for the conversation - I appreciate the chance to compare views and perspectives

  7. Debates about agricultural futures would generate more light and less heat if rich westerners stopped criticising other rich westerners by claiming to speak for the hungry, but I struggle to believe that any informed commentator on global food policy seriously thinks that foot-dragging over organic purity has anything more than a minimal impact on global poverty. The solutions to poverty are to be found in political economy, not agronomy, and what we’ve learned from strongly biotech-focused solutions is that they usually benefit the wealthier strata of small-scale local landholders and entrench their power at the expense of the landless and land hungry, whose relationship with biotech then usually turns out to be a life of plantation toil producing sugar, bananas, flowers etc for the wealthy consumers of the world – if they’re lucky.

  8. Chris,
    Yes, the solutions to poverty are complex. What many subsistence farmers need the most is land ownership rights (for the mostly female farmers), fair farm credit and at least some sort of crop insurance. A little fertilizer, and decent seed help.

    I don't think history would support your connection between exploitative plantations and biotech any more than that flooded crocodile farm for rich people's handbags and shoes is related to biotech.

  9. Steve: Like the way you disproved Ken Cook's "slathering" comment. It's falsehoods like this that has EWG at odds with conventional farming.


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