The Muddled Debate About Pesticides 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 insecticide 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? (It is actually by Chuck Benbrook of the Organic Center in the US and generates a seemingly big number by modeling use over 16 years on hundreds of millions of acres. The increase per planted acre is small). Does Benbrook know about the intensive use of pesticides on crops in Europe? (see graph below).

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 savage.sd@gmail.com.  My Twitter feed is @grapedoc

Sprayer image from North Carolina Crops

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Steve Savage is an agricultural scientist (plant pathology) with >30 years of experience in agricultural technology. He has worked for Colorado State University, DuPont (fungicide development), Mycogen (biocontrol development), and for the past 13 years as an independent. He also has a little vineyard in his back yard near San Diego. His speaking websiet is :"His blogging website is Applied Mythology. You can follow him on Twitter @grapedoc


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69 comments to The Muddled Debate About Pesticides and GM Crops

  • Justin Ma

    “Why do European farmers use so much pesticide? The reason is simple: they have to deal with lots of pests!”

    Let’s not forget the major reason why European farmers use *more* pesticides – they’re more heavily subsidized.

  • One of the things that frustrates me is when people rely on a pound-for-pound comparison. I see both proponents and opponents of GE crops doing it, and I think we need to change the language to fit the real question, and that is what is the environmental and human health impact of changes in pesticide use?

    Charles Benbrook treats a pound of glyphosate as equal to a pound of atrazine as equal to a pound of carbamate as equal to a pound of Bt. Therefore, if there is an increase in the number of pounds of glyphosate that is greater than the reduction in other pesticides, he reports it as an overall increase, even though he knows that glyphosate is relatively benign compared to some of the things that have gone down. Also, when opponents of GE talk about weeds becoming resistant to Roundup, they then also say that GE is causing farmers to switch to more toxic herbicides, which is trying to have it both ways.

    On the flipside I see proponents of GE talk about ‘reduced pesticides’ overall, and reduced insecticides in specific. But what we really want to know is whether or not the usage changes have had a net positive environmental impact. I think proponents should talk about reducing the environmental impact, and give the Environmental Impact Quotient (EIQ) numbers to demonstrate it. We can’t expect opponents to change their approach because it is intimately tied into PR. Some proponents may not want to change – but “reduced/increased pesticides by-the-pound” is the wrong question and the debate stagnates while people continue to use this language.

    • Rob Wallbridge

      Karl – people who point out the development of resistant weeds & the increased use of more toxic herbicides are not “trying to have it both ways”- they are stating two of the obvious consequences of this GMO technology. When the weeds develop resistance, farmers feel forced to add more toxic herbicides to their arsenal in order to kill the resistant species. Last night I read an article by a former Cargill agronomist in a well-respected farm publication stating that 90% of glyphosate-tolerant corn acres and 25% of GT soy acres are now sprayed with a residual herbicide in addition to multiple applications of glyphosate – and that percentage is expected to rise as resistance spreads to more acres and more species. Whether or not GMO crops reduced pesticide use in the short term is certainly a muddled topic, but the sustainability of any reduction seems highly questionable at best.

      • Rob,
        Again, you use the term “toxic herbicides.” Obviously they need to be toxic to plants, but that in no way means that they are toxic to other things or problematic in other ways. Weeds develop resistance to anything over time. There are several species which were selected for by mechanical weed control – things like bindweed or Canada thistle that thrive on being cut into pieces and spread over the field. The herbicides that glyphosate largely replaced in these crops, the sulfonyl ureas I mentioned, were highly prone to resistance. Most people just never heard of resistant weeds until they learned about biotech crops. It is nothing new

      • It’s not clear to me why you think this is a property of GMOs. Can you tell me why it’s different than conventional herbicide resistance?

        • Agreed. Look up BASF Clearfield. They are non-GMO (and are marketed as such, yet raise the same issues.

          • Of course they really are “genetically modified,” just through mutation breeding. That does not seem to attract as much hostility for some odd reason

            • Andre

              Well, the odd reason may be that they do not know.

              In France, they do, assisted in this respect by the weird European Union legislation which defines « genetically engineered » as including mutation breeding, just to exclude the latter from its scope.

              And, having no « real » GM crops to destroy, the voluntary vandals regularly have a go against Clearfield sunflower to keep their activism going.

              • And, having no « real » GM crops to destroy, the voluntary vandals regularly have a go against Clearfield sunflower to keep their activism going.

                Do you have a source on this? I wasn’t aware of this.

              • Oh, I have a source request too – “European Union legislation which defines « genetically engineered » as including mutation breeding” in which laws is this stated? Thanks very much, I appreciate the opportunity to learn more about what’s happening in other countries.

                • Andre

                  This is the controlling piece:

                  Directive 2001/18/EC of the European Parliament and of the Council of 12 March 2001 on the deliberate release into the environment of genetically modified organisms and repealing Council Directive 90/220/EEC

                  http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32001L0018:EN:HTML

                  Article 2
                  Definitions
                  For the purposes of this Directive:
                  (1) “organism” means any biological entity capable of replication or of transferring genetic material;
                  (2) “genetically modified organism (GMO)” means an organism, with the exception of human beings, in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination;
                  Within the terms of this definition:
                  (a) genetic modification occurs at least through the use of the techniques listed in Annex I A, part 1;
                  (b) the techniques listed in Annex I A, part 2, are not considered to result in genetic modification;

                  Article 3
                  Exemptions
                  1. This Directive shall not apply to organisms obtained through the techniques of genetic modification listed in Annex I B.
                  2. This Directive shall not apply to the carriage of genetically modified organisms by rail, road, inland waterway, sea or air.

                  ANNEX I A
                  TECHNIQUES REFERRED TO IN ARTICLE 2(2)
                  PART 1
                  Techniques of genetic modification referred to in Article 2(2)(a) are inter alia:
                  (1) recombinant nucleic acid techniques involving the formation of new combinations of genetic material by the insertion of nucleic acid molecules produced by whatever means outside an organism, into any virus, bacterial plasmid or other vector system and their incorporation into a host organism in which they do not naturally occur but in which they are capable of continued propagation;
                  (2) techniques involving the direct introduction into an organism of heritable material prepared outside the organism including micro-injection, macro-injection and micro-encapsulation;
                  (3) cell fusion (including protoplast fusion) or hybridisation techniques where live cells with new combinations of heritable genetic material are formed through the fusion of two or more cells by means of methods that do not occur naturally.
                  PART 2
                  Techniques referred to in Article 2(2)(b) which are not considered to result in genetic modification, on condition that they do not involve the use of recombinant nucleic acid molecules or genetically modified organisms made by techniques/methods other than those excluded by Annex I B:
                  (1) in vitro fertilisation,
                  (2) natural processes such as: conjugation, transduction, transformation,
                  (3) polyploidy induction.
                  ANNEX I B
                  TECHNIQUES REFERRED TO IN ARTICLE 3
                  Techniques/methods of genetic modification yielding organisms to be excluded from the Directive, on the condition that they do not involve the use of recombinant nucleic acid molecules or genetically modified organisms other than those produced by one or more of the techniques/methods listed below are:
                  (1) mutagenesis,
                  (2) cell fusion (including protoplast fusion) of plant cells of organisms which can exchange genetic material through traditional breeding methods.

      • Rob, let me explain more clearly what I mean about trying to have it both ways. When discussing the transition from other herbicides to glyphosate, the more benign nature of this herbicide is ignored in favor of reporting the pounds of active ingredient applied. But if it is a question of what herbicide may be used if glyphosate is nio longer useful on a field, then they talk about the other herbicide being more toxic. Basically, they are trying to make it sound as if switching to glyphosate is worse than what was before, and then switching back is worse than that. That’s trying to have it both ways and it makes no sense when you think about it.

        • Rob Wallbridge

          OK, lots to respond to here.

          First of all, Steve, I used the term “more toxic” in the same sense that Karl has, that is, speaking in relative terms. However, your suggestion that they are ONLY toxic to plants is patently false and easily disproven: RoundUp, for example, has demonstrated toxicity to aquatic life: http://edis.ifas.ufl.edu/ag248

          On the topic of resistance, it is true that it is not solely a property of GMOs. However, what is indisputable is the fact that glyphosate tolerant (GT) crops have radically altered the selective pressure for resistant weeds in agricultural fields: prior to the advent of these crops, most farms would have “rotated” herbicides along with their crops, given that most post-emergent corn herbicides would be toxic to soybeans, and vice versa. With GT crops, both crops receive multiple applications of the same herbicide year in and year out (a corn-soy rotation is fairly typical across the Mid-West). Indeed, the greatest legacy of GMO crops may be the fact that they greatly accelerated resistance to two relatively “benign” pesticides (glyphosate and Bt).

          Finally, Karl, I appreciate your clarification and agree that strictly-speaking, it is a logically inconsistent argument, unless of course, you take the broader perspective that the switch to the exclusive use of glyphosate was a poor long-term strategy and made the return to more toxic formulations inevitable.

          • Ewan R

            I dunno that you can say it was a poor long term strategy because there was an inevitable return to more toxic formulations.

            First, there isn’t necessarily a return to more toxic formulations in the long term (glufosinate, from what I recall reading in the literature, has an EIQ lower than glyphosate, and is a possible next gen herbicide tolerant trait).

            Second, where there is a return it is back to the status quo, so your strategy has reduced overall environmental impact for its period of utility, the strategy would only be a bad one if it were to end up with a worse than start point impact.

            The acceleration of resistance is, to an extent, not overly meaningful – if you aren’t using the pesticides then sure, no resistance appears, but resistance doesn’t matter, because you aren’t using the pesticides (and resistance has appeared to Bt in non-GM fields, resistance has appeared to many herbicidal modes of action for which no transgenes are utilized – in both cases non-use of the pesticides in question would have retarded or halted the rise of resistance, but to what end?) There is an inevitability to resistance rising to just about any biological control mechanism you utilize (even tillage) – it makes for a poor argument not to utilize any given mechanism though (although there is a very good argument to rotate, and use multiple modes of action, if only to slow the inevitable)

          • Rob, the reference you gave clearly explained that the “demonstration of toxicity” was irrelevant because it was a formulation which is not labeled for use in an aquatic setting and the issue was with the surfactant anyway.

            You are right that use of glyphosate on both crops in the rotation would be problematic, but there was plenty of advice given to avoid that and/or to use a pre-emergent etc. Most growers valued the resistance in soy the most

          • So, you admit it’s true that it’s not solely a property of GMOs, and then you go on to misuse the claim again within the same paragraph?

            Indeed, the greatest legacy of GMO crops…

            This is logically inconsistent.

            There is non-GMO GT. Further, the implication that Bt resistance comes only from GMO is also flat-out wrong. It was observed in 1994 before GMOs in conventional use. http://www.annualreviews.org/doi/abs/10.1146/annurev.en.39.010194.000403?journalCode=ento

            • Rob Wallbridge

              Here we go again…

              Ewan certainly demonstrates the “muddled” aspect of the issue – now it would seem that the “pro” side is trying to have it both ways by suggesting that the pre-GT herbicides were better! :) And of course we can never go back to start point – farmers now have to deal with GT weeds, whether or not they ever employed the technology. I’ll accept the argument about the inevitability of resistance, but I challenge you to find that aspect highlighted in any of the early promotion of the technology!

              Steve, my reference simply demonstrated the falsity of your claim, and if you believe that Roundup never finds its way into aquatic systems, you need to do some more research. Either way, your claim is still false.

              Mary, there is no logical inconsistency here. As I clearly stated before, the “property of GMOs” is the way they radically altered the selective pressure for the development of GT weeds (which to my knowledge, is the only place you’ll find “non-GMO” GT). To be clear, I have never claimed that HT weeds are a GMO property, but the accelerated resistance of a number of species over millions of acres certainly is. That observation is no more logically inconsistent than lobbying for a ban on semi-automatic assault rifles while still allowing the sale of BB guns!

              • Rob, two points. First, Ewan is I think trying to point out that if you stop spraying glyphosate, you don’t have to ‘deal with GT weeds’ because you are just dealing with weeds. If you sprayed herbicide X before, then switched to glyphosate, but then resistant weeds showed up and you switched back to herbicide X, the weeds will not be more weedy than before. Unless herbicide X has the same mode of action as glyphosate, it will not make them more resistant to herbicide X. Again, when you are not spraying glyphosate, the resistance to that herbicide will not change anything else about the plant worth mentioning.

                Second, Mary is not claiming that the weeds are themselves GMO. She is pointing out that there are ways other than genetic engineering to produce crops that are herbicide tolerant. The issue of weed resistance to herbicides is not a GMO-only issue, and the people who are the most vocal about the downsides to herbicide tolerant crops are ignoring herbicide tolerant crops achieved through conventional breeding. You gun analogy fails because BB guns don’t kill people like assault rifles do. However, herbicide tolerant crops operate exactly the same whether they were made through genetic engineering or conventional breeding. A more appropriate analogy is banning assault rifles made by one company but allowing identical ones from another company.

              • Ewan R

                now it would seem that the “pro” side is trying to have it both ways by suggesting that the pre-GT herbicides were better!

                How exactly? They weren’t better, or worse, than themselves. So if one returns to the old ways you return to the status quo, this isn’t arguing that anything is better.

                Glufosinate would only be usable (as far as I know) in combination with a trait for resistance, which means that the older herbicide (and is it really older? Glyphosate is was hardly new when it took off as a crop protection chemical) is only better in conjunction with new technology. This is another model of advancement, and one that is oft overlooked – constant development, as resistances arise new traits take over, it is conceivable that by rotating traits on a mid to long term basis one could stave off total resistance, or by stackign traits, or by rotation on a year by year basis (either with stacked, or single traits).

                Your millions of acres of HT weeds wouldn’t matter either way in a world where GT crops didn’t exist. There would be no G use on those acres, so the weeds there may as well be GT for all the difference it makes. The only time a GT weed is a problem is when you use G as a weed control system, if you aren’t using G then their propensity to drop dead upon application of G is immaterial.

                • Rob Wallbridge

                  OK, we obviously need to inject some reality into this discussion:
                  First, let me clarify with Karl and Mary: Mary used the term “non-GMO GT”. Perhaps she meant to say “non-GMO HT” but I can only reply to what it stated.

                  Secondly, although my analogy may have been exaggerated, yours is inaccurate and fails to acknowledge the key point I have been trying to communicate all along, so let’s try again: GMO GT crops have vastly accelerated the development of HT weeds by increasing the selective pressure for such. A more accurate metaphor may be to compare a semi-automatic assault rifle with a single-action shotgun: both kill people, but one at a much greater rate than the other. All weed control technologies provide selective pressure, but the manner is which GMO GT technology has been used has radically increased that pressure, and we’re seeing the results.

                  Finally, all of your theoretical postulating about the relative impact of GT/HT weeds seems to be based on a poor understanding of how things actually work on real farms. First, glyphosate was and continues to be used to control weeds in non-GMO GT crops, extensively as a pre-plant burndown, and often as a pre- or post-harvest treatment as well. The same would apply to glufosinate. In addition, more selective herbicides would be applied to the crop itself, in accordance with the crop type. GMO GT crops replaced this variety of herbicide applications with multiple applications of G. G was a very convenient and cheap (especially with the patent expiration) method of broad-spectrum weed control at times of the year when crop impact didn’t matter. Farmers with GT weeds have lost that tool.
                  The other issue you overlook is that farmers usually don’t realize they’ve got GT weeds until their weed control strategy fails: they apply G expecting to achieve control, and then it doesn’t work. In the best-case scenario, they go spend more time and money on another product; in the worst-case scenario, they lose some or all of their crop because they can’t exercise another option in a timely fashion.

                  It’s fine to debate things based on theory and logic, but once in a while, you need to consider how the real world functions.

                  • Rob–I specifically used GT because that was your example. Are you unaware that it’s possible to create non-GMO GT?

                    The first spud product they plan to release is a non-GMO Roundup-resistant Russet Burbank.

                    http://www.capitalpress.com/newest/JO-Canola-070512

                    Why would that be different that a GMO version in the outcome?

                    • Rob Wallbridge

                      Thanks, Mary. Yes, I was unaware of this development – as I said, the weeds were the only non-GMO GT plants “to my knowledge.” Thanks for expanding my knowledge.
                      And as you suggest, the outcome of that development (in terms of potential weed resistance) wouldn’t be any different, although you would obviously need to account for the acreage planted to that crop and the other crops in the rotation. Which continues to be the point I make about the GT crops currently on the market!
                      I keep re-reading my posts here to try to understand why they are evoking so much confusion and defensiveness: I think I’m being very clear in what I’m talking about, but somehow people continually try to ascribe some sort of blind, irrational hatred of anything GMO to what I’m saying. Perhaps it’s only because it makes it easier to dismiss, I don’t know…

                    • Rob, I went back through the previous comments to find the part where “people continually try to ascribe some sort of blind, irrational hatred of anything GMO to what I’m saying,” but I can’t find it.

                    • Well, here’s the problem:

                      …although you would obviously need to account for the acreage planted to that crop and the other crops in the rotation…

                      And this is exactly what we are saying. It’s not a GMO-ness issue. It’s stuff *besides* that which you keep blaming on GMOs. You can’t seem to separate them, and we do.

                      If you hate how plants and herbicides are being used, fine, but stop blaming it on their GMOness.

                    • Rob Wallbridge

                      Mike, you can’t find it because it’s subtly implied, especially in MaryM’s posts, and most clearly in her last one. MaryM, it’s not clear to me where, in any of my previous posts, I have “blamed” anything on the “GMOness” of HT crops – I believe I have taken pains to point out a number of times my understanding that it is not inherently a “GMO-only” issue. I challenge you to find a contradiction.

                      The only place where I made a general reference to GMOs was when I noted that “the greatest legacy of GMO crops may be the fact that they greatly accelerated resistance to two relatively “benign” pesticides (glyphosate and Bt).” So please let me clarify:
                      I am NOT blaming the GMOness of these two traits for the legacy they are leaving. I am simply stating the FACT that these crops are GMO, that they compose the overwhelming majority of GMO crops planted in the world today, and that the next big GMO release here in North America will be 2,4-D HT crops. If that fact makes you feel uncomfortable or defensive, I’m sorry, but that is reality. Maybe someone else here can explain to me the utter failure of the biotech industry, despite almost 20 years and billions of dollars, to fulfill all of its hype and promise, but don’t blame me if I don’t buy into it. And if, in another decade, HT crops and the havoc they’ve wreaked (http://farmindustrynews.com/herbicides/glyphosate-resistant-weed-problem-extends-more-species-more-farms) only form a sad and unfortunate footnote in the history of GMOs, I’ll gladly admit my error.

                      Until then, I won’t allow the reality of the impact of GMO crops be separated from your theoretical delusions about the unimpeachable holiness of their “GMOness”. And I will not apologize for looking at things from the perspective of someone who lives and eats and farms in the real world, rather than people who seem to prefer to keep things tucked into neat little theoretical boxes.

                    • pdiff

                      Rob Wallbridge:

                      And if, in another decade, HT crops and the havoc they’ve wreaked (http://farmindustrynews.com/herbicides/glyphosate-resistant-weed-problem-extends-more-species-more-farms) only form a sad and unfortunate footnote in the history of GMOs, I’ll gladly admit my error.
                      I’m curious about the quality of this survey, conducted by a company that profits off of resistance problems. The sampling methodology would be important here. It is also known that farmers tend to over report resistance problems. Clearly, resistance has increased. I’m not arguing that, but the levels they report (49%) seem extreme, not mention they don’t account for the level of resistance; one plant, a dozen, 400 acres, etc. The numbers reported by the Weed Science Society of America are probably more realistic. Not, IMO, wreaking havoc.

                    • Ok, Rob, you keep your aim on GMOs. Go get ‘em!

                      Then they’ll go away, replaced by the next strategy–which very well may not be GMO.

                      And when the non-GMO RR comes along, or when other non-GMO HT becomes the issue, come back to me and we’ll talk more. Because then we can talk about the actual issue of resistance instead of your problem with one method of plant development.

                      Of course, I expect you’ll move the goalposts in some other manner then. But it will be fun to revisit still.

                    • Mary,
                      By the way, the next non-GMO HT lines will come from Cibus Genetics which uses a really cool, directed mutagenesis approach that allows them to only change desired bases in specific spots in specific genes.

                      http://www.capitalpress.com/newest/JO-Canola-070512

                    • Rob Wallbridge

                      Rob Wallbridge, January 31, 2013 at 10:32 am: “On the topic of resistance, it is true that it is not solely a property of GMOs.”

                      Rob Wallbridge January 31, 2013 at 3:00 pm: “To be clear, I have never claimed that HT weeds are a GMO property.”

                      Rob Wallbridge February 4, 2013 at 10:03 am: “All weed control technologies provide selective pressure, but the manner is which GMO GT technology has been used has radically increased that pressure.”

                      Rob Wallbridge February 4, 2013 at 12:56 pm: “And as you suggest, the outcome of that development (in terms of potential weed resistance) wouldn’t be any different.”

                      Rob Wallbridge February 4, 2013 at 10:00 pm: “MaryM, it’s not clear to me where, in any of my previous posts, I have “blamed” anything on the “GMOness” of HT crops – I believe I have taken pains to point out a number of times my understanding that it is not inherently a “GMO-only” issue. I challenge you to find a contradiction… I am NOT blaming the GMOness of these two traits for the legacy they are leaving.”

                      I don’t see an “aim on GMOs” and I certainly don’t see “moving goal posts.” If the goal posts seem like they’re moving to you, it’s probably because you’re a little dizzy from running around in circles! For more proof, read below, where Daws, Steve and I have an entire conversation without ever bringing up the “GMOness” of anything.

                      The only person here fixated on GMOs seems to be you, my friend.

                      But just to be extra clear, any HT crops (GMO or not) are a silly, short-sighted, counter-productive exercise, with the only long-term benefit accruing to the corporate bottom line of the herbicide manufacturers and marketers.

                    • I’m sure you’re having trouble keeping track Rob–it began right at the beginning of this thread:

                      Rob Wallbridge January 29, 2013 at 6:16 pm

                      the obvious consequences of this GMO technology

                      And then again, after admitting it’s not GMO technology:
                      Rob Wallbridge January 31, 2013 at 10:32 am

                      Indeed, the greatest legacy of GMO crops

                      Obvious. Legacy. About what? GMOs. Not HT.

                      I am delighted that you think you will be able to keep that straight in the future. I think that’s real progress for you.

                    • With all due respect, I don’t think this line of discussion is useful. Once someone restates something, let’s let them restate it. I know I make mistakes and misspeak (not that I’m saying anyone did or did not do that that here), and I really appreciate it when people let me restate so we can move on with the conversation.

      • Andre

        « When the weeds develop resistance, farmers feel forced to add more toxic herbicides » ?

        When weeds develop resistance, farmers are forced to change or refine their weed control strategy.

        « Add more… » raises the question of the starting point. In former times – pre-HT crops – farmers were bound to use a cocktail of herbicides to control all weeds (depending on the flora to be controlled and, quite frequently, the resistances that had appeared over time. This is stage 1. With the advent of HT crops, farmers could do with just glyphosate. Perhaps more pounds, but better EIQ. This is stage 2. With the emergence of glyphosate resistant weeds (mind it: the first of them appeared in non-GM fields) they have now to use another herbicide to control those weeds. This is stage 3. With the widespread usage of glyphosate, it is also advisable to use two herbicides to limit the appearance of resistance.

        So, it is certainly « more herbicides » compared to stage 2, in terms of pounds and EIQ, and probably still better than stage 1 in terms of EIQ.

  • Ewan R

    How do the US numbers match Europe? Preferably normalized by area and EIQ? (as the presented graph basically just does what Benbrook does, albeit without making ludicrous claims)

    Inquiring minds and all that.

    Slathered, soaked in, doused with, etc etc are all terminology one becomes increasingly frustrated with when discussing pesticide use on crops – emotive descriptors designed to confuse (or indicative of a complete lack of understanding).

    Ideally the discussion should be around the environmental impact (as well as the rather obvious discussion around efficacy and cost of various systems, when you’re operating at practically negligible environmental impact does it matter so much if you reduce the impact further while making the system far harder to use, or far more costly?) but this gets lost often (although not always) either because it doesn’t paint the right picture, or because it lacks simplicity.

    • I’m curious about that as well. One could probably match parts of Europe to parts of the US approximately by climate and then compare pesticide use per area (preferably normalized by EIQ). Sounds like a fun and publishable research project if anyone has free time ;)

  • I understand the desire to get the claims right. But will that really be more effective than this?

    http://kissedafarmer.blogspot.com/2012/11/a-buggy-full-of-gmo-cotton.html

    Thanks to the genetic trait in our cotton that makes it resistant to the boll worm, we did not spray one drop of insecticide on our fields this year. Not one drop. Because we don’t have to spray for the boll worm any longer, the beneficial insects are flourishing and naturally control the other minor pests. Now, if we planted non-GMO cotton, like the farmers in Brazil that Daniel met last spring, we might have to spray our cotton up to 13 times with insecticide. That’s what the Brazilian farmers told him they have to do in order to save their non-GMO cotton crop. Once they start spraying for the boll worm, then they have to spray for other pests because the beneficials are gone. 13 applications verses 0 applications. In my book, there is no comparison.

    How would you re-write this to be accurate?

    • How about:
      “We used GE cotton to reduce the environmental impact of insecticide sprays on our cotton fields by 100%”

      • Ah, see, I thought you would want calculate out the amount of Bt involved here now. Because there is Bt (but much more targeted of course). So if you want to have it accurate you’d have to include that usage. I thought that’s what you meant.

        • Back in the early 90s when I worked for Mycogen we sold a great deal of sprayable Bt in the cotton market. It was actually our CellCap technology where we were expressing the protein toxin in genetically engineered Pseudomonas fluorescens which was then killed is such a way that the protein was still functional. We were selling a product called Match which included both a Cry1ac and a CryF for resistance management purposes. Growers used it as part of the spray program, but to have done it for the whole thing would have required sprays every few days. Expressing it in the plant is soooo much more efficient.

          Oh, of course the organic growers couldn’t use our product

          • Ah, I was wondering about that. I was reading about a spider toxin the other day, but it is grown in a culture system. So that’s a GMO. However, the resulting protein would just be a plain old string of amino acids that could occur naturally.

            I didn’t know if that would be allowed in organic systems. I guess not then.

            Here’s the protein/system: http://www.vestaron.com/index.php

      • Janet

        I’m interjecting here to wonder if anyone has done any studies on the environmental impact of having that Bt in the whole corn plant, from silks to roots, and does it break down in the field, soil, etc. It’s my understanding that sprayed on Bt would breakdown in sunlight, but it is different when it’s actually in the genes of the plant.

        Thank you. I so appreciate the patient and civil discussions on this website after doing research other places for the past two months!

  • I agree that the best way to compare is for the same crop on a per unit area basis and taking into account some measure of potential environmental impact, but that isn’t easy to do. For instance the European data I found has big categories like “cereals.” I’m less familiar with data sources for Europe so maybe there is something more comparable to the detailed USDA data that is available, but probably nothing as transparent as the California use data (CALPIP).

    The point; however, is that in both the US and Europe (and many other places), if a product is registered for use it has undergone extensive risk assessment and is very unlikely to be any sort of environmental problem. Of course it is great when a crop like cotton needs so many fewer sprays. That was also the case for potatoes until that biotech crop was killed by brand protectionism driven by anti-GMO fervor. I should do a post about that – “How anti-GMO activism increases pesticide use.”

    • Not a bad idea. I’m curious what the literature says about the New Leaf potato and its effects on insecticide use. I also know a researcher looking into the effects of having organic potato farms with their pest load next to conventional farms, with the goal of looking into whether colorado potato beetles from one farm are negatively affecting another. I could ask how that research is coming.

      • Karl,
        There probably isn’t much literature on New Leaf potatoes because they were only planted for a short time before MacDonalds/Frito
        Lay shut them down for brand protection reasons. The growers I talked to during that brief window said that they not only didn’t need to spray for Colorado Potato Beetle, they didn’t have to deal with several minor pests because the beneficials were taking care of them. The virus resistant potatoes were just beginning to get approval when the whole thing crashed and that would have obviated late season sprays for the vector aphids. Again, this was all shut down for brand protection reasons.

    • Andre

      On January 29, 2013, BASF announced that they were withdrawing their applications for the cultivation in the European Union of GM potatoes ‘Fortuna’, ‘Amadea’ and ‘Modena’.

      ‘Fortuna’ is a late-blight resistant variety, with two resistance genes from a wild potato. So it is essentially within the potential range of the « normal » genetic diversity of the potato, except that the transfer of the two genes using the cumbersome interspecific crossings never succeded. Anyway, exit genetic resistance and your story will be « How anti-GMO activism maintained pesticide use. »

      ‘Amadea’ and ‘Modena’ are amylopectin starch variety (like ‘Amflora’, which has been withdrawn from the market. It is hard to say for sure whether such varieties had economic potential since industry has to adjust to their characteristics. But your story may be « How anti-GMO activism prevented more environment-friendly industrial processes ».

  • Daws

    Is there anyway to get data on comparative risk for birth defects due to exposure to the chemicals during pregnancy with organic vs. conventional? I don’t ever worry so much about LD50 levels for my own intake, but am more concerned about exposure of female farmers, wives, nearby residents etc. that may be having kids. If someone eats a slightly toxic chemical they might feel sick for a little bit I imagine, but a birth defect to your child is something that never goes away (or costs a lot to fix if possible). So are there any stats on that?

    (Data on herbicides would be welcome as well, as I’ve heard more of problems with them than pesticides personally.)

    • Rob Wallbridge

      You’ve hit on some very important questions, here, Daws, that point to serious flaws in the regulatory system for pesticides. Firstly, “safe” levels are determined using adult or adolescent models, and not children, infants, or those in utero. Secondly, toxicity is determined using the notion that “the dose makes the poison” when in fact a growing body of research challenges this notion, especially as it relates to hormone-mimicking chemicals, which is a property of many pesticides. Thirdly, chemicals are tested in isolation from one another, and usually it is only the “active” ingredient that is evaluated for safety, not the actual product as used. The complete formulation can have very different effects, as is demonstrated when one compares glyphosate and Roundup: http://edis.ifas.ufl.edu/ag248 In addition, we are rarely exposed to a single pesticide – they are usually found in combinations, and the combinations of pesticides and/or other substances can have synergistic or layered effects. This is demonstrated here: http://www.zoology.wisc.edu/faculty/Por/pdfs/endopt1.pdf and here (part 2): http://www.zoology.wisc.edu/faculty/Por/pdfs/endopt2.pdf

      I’m not aware of any comparative studies related to birth defects, but it’s not hard to find research pointing to the in utero effects of pesticides, for example: http://www.zoology.wisc.edu/faculty/por/pdfs/mice.pdf In addition, there’s research demonstrating that an organic diet significantly reduces exposure to pesticides: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367841/

      Hope this helps!

      • Daws

        To be clear, one of the reasons I brought it up is that it can be another plus for GM, since it can greatly reduce the need for pesticides, and allows for use of safer herbicides. For the only study I’ve seen hinting at any connection between birth defects and round up was one acting under very implausible exposure conditions. Basically I believe they injected it straight into where the embryo was growing, into or through the placenta…

      • Daws

        “there’s research demonstrating that an organic diet significantly reduces exposure to pesticides: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367841/

        I also feel like I’ve heard things somewhat counter to the above statement, though I couldn’t cite for the life of me. Perhaps someone here can? One thing was measuring the residue left on the crops, where we are just now starting to do this but not in a meaningful way that could tell us the relative difference between organic and inorganic, I believe the reason was that organic crops got exempted from this monitoring.

        Aside from that though the point was not exposure to sprays by diet but by environmental exposure in use on the fields, to the farmers, the neighbors, etc. and if organic sprays are used in greater frequencies, in greater doses, sometimes with longer half-lives this can only mean greater risk of exposure to the environment and thus the workers and neighbors.

        I’m playing fast and loose here I know but perhaps someone can back me up on this?

        • Daws,
          The fact is that we don’t know that much about the residues on organic crops because most of what is used on them is not detected by the analytical techniques used to check for residues of synthetic pesticides. There has also been little or no testing of organic crops to demonstrate compliance – something that will only start to a small degree in 2013 and which still won’t look for the most likely residues like copper compounds. I wrote a post about this a month or two back

          http://appliedmythology.blogspot.com/2012/12/pesticide-residues-on-organic-what-do.html

          Most of what is sprayed on either organic or conventional crops in modern farming is far lower in risk than people imagine (see http://appliedmythology.blogspot.com/2012/09/pesticides-probably-less-scary-than-you.html), but copper salts which are extensively used as fungicides on some organic crops would be some of the least desirable options. They are used at high rates, must be frequently re-applied, are hard on aquatic invertebrates and are very persistent in the environment. The conventional grower has many options that are less toxic to mammals, much lower impact on the environment, are used at far lower rates with less frequent applications and do a far better job of disease control.

  • Rob Wallbridge

    Wow. I hope everyone here recognizes that if I had made these same wide-sweeping, vague, unsubstantiated, and un-referenced claims about GMOs and/or pesticides, EVERY SINGLE ONE OF YOU that have posted on this thread would be down my throat with arrogant and condescending references to the emtional, irrational, “anti-science”, “anti-technology” proclivities of “radical activists” like me. And yet when Steve and Daws use the same tactics to slam organics, it goes without comment. Some objectivity, folks.

    So let me say it: CITATIONS NEEDED!!!!! When you can provide a factual basis for your claims, then we’ll talk. Steve, you may want to to start by looking into the organic standards to learn more about the criteria for approval of pesticides and the restrictions on their use. Your blog posts made it clear you’re relying on a number of popular yet false assumptions.

    I thought Biofortified was about fact-based discussion, not “playing fast and loose.” But maybe those criteria only apply to certain perspectives?

    • Rob,
      Sorry, but I am extremely familiar with the process for approval of pesticides for organic (NOP, OMRI) and the fact that products like Copper Sulfate, Lime Sulfur, etc are allowed is a matter of public record. Those are regulated by the EPA as well for environmental and health risk assessments, so I’m not saying that they are dangerous – just that there are better options.

      • Rob Wallbridge

        The blog posts you reference above give the clear impression that the only criteria for organic pesticides is that they are “natural” and that organic producers can use them without any restrictions or monitoring requirements. Both claims are false.

        Either you don’t possess the knowledge you claim to have, or you deliberately do not choose to share it with your blog readers. Either way, a correction is in order.

  • Rob Wallbridge

    “Just sprayed willy nilly into the environment” Really, pdiff? Is that how you think farmers manage pesticide application? That’s disrespectful and insulting.

    For a full overview of the management efforts (including resistance development) check this out: http://www.tfrec.wsu.edu/pages/organic/fireblight

    • Ok, ok, it was disrespectful and insulting to growers. I apologize. To me, your complaints about HT/GT GMO use by growers, however, can be viewed in the same light.

      While I may have been snarky on the antibiotics issue, it is not incorrect to say that they have been over used. From the first link in your reference:

      For the past several decades, the most common control for fire blight has been the use of antibiotic sprays along with a predictive model of disease development. The two antibiotic materials used are oxytetracycline and streptomycin. The former is primarily used in our region, while Midwest and Eastern growers rely on the latter. Streptomycin is now generally ineffective in the Pacific Northwest due to resistant disease strains, while tetracycline can provide 85-95% control if application is timed correctly.

      Organic fire blight control and the NOSB

      The parallels with GMO HT are notable. Growers found a cheap, easy, and effective control measure. They applied it and eventually resistance followed. Now they are left with a less effective “tool” as you say. They are, hence, employing more sophisticated means of using the control such as limited application and coordination of application timing with production to improve control. They are evaluating other replacement tools, that themselves will likely lead to similar resistance problems. In the mean time, the deadline for retiring the current technology keeps being extended because it is just too useful/necessary to eliminate.

      It is also interesting and unfortunate to note that the Organic community chose to follow this long term “synthetic” and unsustainable antibiotic path, while shunning a GM resistant solution that exists and could be readily implemented.

      • Snarkiness aside – play nice, folks! – I do see a lot of similarities anytime you see a move towards an easy solution and away from integrated pest management. IPM is harder, and it can be easy to stray when presented with a solution that works and is fairly cheap. Of course there are differences between HT in conjunction with weed control and and blight control with antibiotics, but both are broad spectrum and used instead of other, more complex methods. This re-emphasizes to me that it is not a GM problem, not an HT problem, not a conventional problem, not an organic problem – it’s a farming problem – and it’s systemic! What’s the solution – something I often harp on, extension. Farmers need access to resources they can trust, who aren’t trying to sell them anything, who understand the local situation. How can we effectively communicate this need for extension to congress, who keeps cutting it? I think a call for better extension funding (perhaps a White House petition?) would be useful, but it would be best if it came from both conventional and organic farmers, supported by NGOs and farming groups from both sides.

        It would have been pretty awesome to have disease resistance built in via breeding or GM, keeping the antibiotics available for other uses. One related example that comes to mind is scab resistance in apples – you can either spray a ton of fungicide, waiting 20+ years for someone to breed resistance into varieties you want to grow, or you can just engineer the resistance trait right into the variety you want. Resistance (however it was developed) can be a really important way to boost yields and reduce pesticide use.

        • Janet

          Seems like the obvious choice is one you didn’t mention, growing the varieties already available that are scab resistant in your environment. I think your extension comment is good as well, but in my experience as a master gardener, the programs are as much heavily influenced by corporate thinking and products as they are by local conditions, experience, and knowhow.

  • Are we sure that there are restrictions on all pesticides used in organic? Especially ones that might be created on-farm? I may have gotten less than accurate info, but I’ve heard from various sources (academics, farmers) that things like herbal extracts and essential oils can be and are used without EPA or other approval. This worries me greatly, as we all know that may plant extracts and oils can be extremely potent and even harmful to humans or other organisms, depending on the concentration used. Neem is classified as a pesticide, so here’s hoping that is properly regulated, but what about clove, lavender, or rosemary extracts and oils, for example?

    I guess I just don’t know that much about this area – need to look more at EPA. Weed oils are prohibited, but what is defined as a weed in this context? What about extracts? Especially homemade? This site says homemade pesticides are prohibited in the UK, but what about the US. This EPA page actually concerns me very much, saying that they don’t require as stringent of testing, and start out with the assumption that “biopesticides” are safer… hmm. They say that biopesticides are more targeted which is true for some things like hormones and Bt, but not for so many other things, like oils and extracts. I have so many questions about this area! It’s frustrating, since I’m reasonably knowledgable about conventional pesticides. Anyone know more about this?

    Some general sources: one example of a site advocating the use of essential oils for pest control, some extracts listed on Wikipedia, a peer-reviewed article about “natural” pesticides, advice on how to make your own “organic” pesticides (literally, in this case, since quite a few include petroleum!), “natural” pesticides sold for use in gardening (how are these regulated? can they be used for commercial production?)

  • Rob Wallbridge

    Hi Anastasia,
    My expertise is more with the Canadian Organic Standard, and here, the pesticide (and drug) regulations trump the organic standards:

    Organic operations in Canada remain subject to all applicable laws and regulations. Substances that appear in CAN/CGSB-32.311, Organic Production Systems — Permitted Substances Lists, are subject to the Pest Control Products Act (PCPA) or the Food and Drugs Act (FDA) when used in Canada as pesticides or disinfectants. Health Canada’s Pest Management Regulatory Agency (PMRA) is the federal authority responsible for the regulation of pest control products (including sanitizers) under the PCPA and Regulations. Disinfectants are regulated by Health Canada’s Therapeutic Products Directorate (TPD) under the FDA and Regulations.
    Substances that appear in CAN/CGSB‑32.311, Organic Production Systems — Permitted Substances Lists, are subject to the Food and Drugs Act (FDA) when used in Canada as veterinary drugs destined to food‑producing animals and to the Feeds Act (FA) when used in Canada as livestock feed. Health Canada’s Veterinary Drugs Directorate is the federal authority responsible for the regulation of veterinary drugs under the FDA and Regulations. Livestock feeds are regulated by the Animal Feed Division
    of the Canadian Food Inspection Agency under the FA and Regulations and the Health of Animals Act and Regulations.”

    In other words, you can’t use something as a pesticide on an organic farm unless it is specifically registered as a pesticide by the competent authority. I would be surprised if the NOP was different, but I’d need to do more research to find a reference.

    While we’re on the topic, it is very important to note that everything you read about as being “organic” and “natural” on the Internet doesn’t by any stretch of the imagination mean that it is permitted in certified organic production. This is why people shopping for organic products at their local farmers’ market or whatever need to look for proof of certification – this means that all of their inputs have been evaluated for compliance!

    • Rob Wallbridge

      Sorry for the wacky formatting there – need to learn more about using those HTML tags!

    • That’s very useful, thank you, Rob. I’m reasonably certain the US organic regs have something similar, hopefully someone familiar with them will help us out. Although, that blanket assumption by the EPA that naturally sourced pesticides are safer does not make me feel any safer. Of course, any chemical natural or not can be harmful depending on how it is used, etc. This reminds me of the goofy US law that supplements are exempt from safety or efficacy testing, even though we all know that herbal remedies can be dangerous if taken improperly, just like any drug.

      This is an interesting argument for consumers to choose certified vs non-certified. At farmers’ markets you see lots of folks selling “near organic”, “beyond organic”, “sustainable”, and similar without the actual organic certification. I have some sympathy for farmers who are doing everything organic requires yet don’t want to do the paperwork and a lot of sympathy for farmers who are mostly organic yet don’t want to lock themselves out of options they might feel they need to use, depending on their specific integrated pest management needs, soil needs, etc. Yet, if they aren’t certified, they may very well be using un-approved, un-tested materials which could be causing more environmental harm than they think. Heck, non-organic farmers might be using these methods as well, unless these are specifically prohibited – again I do not know whether US farmers are allowed to use any substances as pesticides that aren’t specifically listed as pesticides by the EPA.

      This does make me wonder, though, about the companies offering various herbal remedies for agriculture. Oh my – I just did a search for “organic pesticides” to see what I could find. I have been trained (thanks, US Army!) to read pesticide labels, so was hoping to find one that might provide information about how it is regulated by the EPA. I found a label for Weed Zap®, made of cinnamon and clove oil, that give us the scoop!

      This product is exempt from registration with the Federal EPA under section 25 (b) of FIFRA. WEED ZAP has not been registered with the Environmental Protection Agency. JH Biotech, Inc. represents that this product qualifies for exemption from registration under the Federal Insecticide, Fungicide and Rodenticide Act.

      So, it doesn’t have to be registered, and since part of registration is proving safety, it doesn’t have to prove safety. The MSDS does not include any of the info that I’m used to seeing about LD50, etc. supporting the idea that safety testing is not required. Still, that does not answer our question of whether or not something like this is allowed for US organic agriculture. However, the company says it is “is suitable for organic production”.

      PS – no worries about the formatting! I fixed it. You can use < blockquote > and < /blockquote > around the areas you want to show as quotes (without the spaces). I’m not sure why the “You can use these HTML tags” thing at the bottom shows it differently :)

      • Anastasia,
        I too am a bit worried about the very different handling of natural products by the EPA. I’m sure that most are perfectly fine, but the system as it is could lead to an unexpected problem. There was a case a few years ago of a fungal fermentation product which produced some volatiles that were quite effective as a bio-fumigant. It showed considerable promise as a post harvest solution for Botrytis on grapes in storage, and some were thinking if it could be scaled it could be a methyl bromide replacement. At some point it was discovered that one of the several volatile chemicals it made was carcinogenic. I’m not sure how that came up because chronic testing like that isn’t required for things on the natural product track in most cases. Obviously it was never commercialized.

        There was another case of a bacterial fermentation product which was a bio-insecticide. In the process of trying to optimize the output of the fermentation (a normal step for all biologicals before and even after registration), it started making a herbicidal compound as well. The company was eventually able to find ways to separately optimize fermentations for each activity, but what it shows is that intermediary metabolism is tricky and it is necessary to keep checking toxicology with any change in bio-production protocols.

        When I worked for many years in the biocontrol business it was sort of nice not to meet the sort if negative response one experiences with synthetics or biotech, but I knew that it was based on most people’s naive assumptions about the wonderfulness of “natural.” Nature has lots of great, benign elements but it also has some unbelievably nasty things as well

      • Rob Wallbridge

        This is a totally valid observation, Anastasia:

        Yet, if they aren’t certified, they may very well be using un-approved, un-tested materials which could be causing more environmental harm than they think. Heck, non-organic farmers might be using these methods as well, unless these are specifically prohibited – again I do not know whether US farmers are allowed to use any substances as pesticides that aren’t specifically listed as pesticides by the EPA.”

        In my backroad travels, I’ve heard a number of “folk remedies” for various problems encountered on the farm, from both organic and non-organic farmers. Some are probably completely harmless (and ineffective) and some may be “effective” in more ways than desired! (It’s a little ironic to hear some people from one side argue that herbal remedies (for example) are useless but they shouldn’t be allowed because they could be dangerous, while certain others argue that they are effective but shouldn’t be regulated because they can do no harm!)

        In most cases, however, it is only the certified organic farmers who every year are required to submit detailed plans of their management practices, keep detailed records, and have those plans and records reviewed on-site by an independent inspector. That’s changing as more and more Quality Assurance and GAP programs come into force, but I would argue that, at the moment, certified organic farmers probably have less opportunity to stray than non-certified and non-organic growers.

        The bottom line, of course, is that everyone is trying to produce a safe product, using the knowledge and tools they have available. Which goes straight back to Anastasia’s previous comment about the need for unbiased, well-informed extension!

  • Steve (or anyone else for that matter), general pesticide/herbicide question: how does water solubility of your average pesticide/herbicide affect its potential hazard to us and/or the environment? I’m currently looking at microbial desulfonation of aromatic sulfonates (some pesticides but also including synthetic dyes and detergents). I’m a biologist so my chemistry is a bit shaky. Removal of the sulfonate group should make these compounds less soluble, right? Is that generally a good or a bad thing for the environment?

    • Tom,
      Yes, in general for a pesticide to be highly water soluble is problematic. It can move into ground water and into streams in runoff. Most pesticides are now fairly lipophillic. This is good for the waxy surface of leaves and it leads to binding to soil to prevent leaching. There is still a need to minimize tillage and increase the water infiltration rates with rain-fed soils so that the soil particles are not eroded into surface water.

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