Genetically Engineered Crops in the Real World – Bt Corn, Insecticide Use, and Honey Bees

, former senior scientist, Food and Environment | January 10, 2012, 6:01 pm EDT
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One of the most frequently mentioned benefits of genetically engineered crops is a reduction in chemical pesticide use on corn and cotton. These chemicals typically kill not only pest insects but also beneficial insects that help control pests or pollinate crops. They may also harm other friendly organisms like birds.

Honey bee on an apple blossom. USDA photo

But in reality, corn engineered to kill certain insect pests—AKA Bt corn—has mainly resulted in the replacement of one group of chemical insecticides with another. Previously, corn may have been sprayed, or soil treated with chemical insecticides to control several insect pests, especially corn rootworm. Bt has largely eliminated (at least for the time being) the demand for insecticides to control rootworm or European corn borer.

But those who tout the benefits of GE fail to mention that today virtually all corn seed is treated instead with chemical insecticides called neonicotinoids to ward off several corn insects not well controlled by Bt toxins. And while almost all corn is now treated with insecticide via the seed, substantial amounts of corn went untreated by insecticides prior to Bt. For example, corn alternated (rotated) with soybeans from year to year usually needed little or no insecticide treatment, and only five to 10 percent of corn was sprayed for corn borers.

Dead bees

A new publication by several academic entomologists on the impact of neonicotinoid insecticides on honey bees shows that such seed treatment may be having serious repercussions. Previous research has linked neonicotinoids to bee deaths as a possible contributor to colony collapse disorder, which is wreaking havoc on bees across the United States.

The new research is important in showing that when neonicotinoid insecticides are used as seed treatments, they can migrate through the soil or through the air in dust to other plants near (or in) corn fields, like dandelions, which honey bees prefer as a pollen source. It was already known that this type of insecticide can travel through the plant as it grows, and this study also shows corn pollen contaminated with this insecticide and substantial corn pollen use by honey bees.

Importantly, the amount of the insecticide found in and around corn fields is near the range known to kill honey bees, and dead bees collected near treated fields contained insecticide residues. It is also known that sub-lethal doses of these insecticides can disorient bees, and may make them more susceptible to pathogens and parasites.

There are a few pieces of the puzzle that still remain to be put into place, but it is looking likely that neonicotinoid seed treatments are harming U.S. honey bees.

Let’s get real

Other research indicates that corn seed treatment is harming other types of beneficial insects. An extensive study in the U.S. Northeast on many types of beneficial beetles that are found in corn fields showed that neonicotinoid seed treatments likely harmed several of these species, although other species may fill in. This study was limited to beetles, did not include other beneficial insects, spiders and mites, and did not examine the implications for crop damage. Other research has shown that reductions in beneficial organisms can result in decreased crop yields.

A pirate bug kills whiteflie nymphs, a pest of many crops. USDA photo by Jack Dykinga.

In general, current data suggests that the new, ubiquitous seed treatments that have accompanied Bt corn are just as harmful as the insecticides they are replacing.

And it illustrates that the impacts of GE technology must be considered more broadly than just direct harm from an engineered gene or protein. As the authors of one of the studies wrote: “Field experimentation must consider the effects of these broader systems for realistic evaluation of currently deployed transgenic crops.”

University of Illinois entomologist Mike Gray, an expert on corn rootworm, summarized the state of U.S. corn production in a recent research article: “The current lack of integration of management tactics for insect pests of maize in the U.S. Corn Belt, due primarily to the escalating use of transgenic Bt hybrids, may eventually result in resistance evolution and/or other unforeseen consequences.”

It is not incidental or coincidental that corn seed—and seed from more and more other crops like soybeans—is being treated with insecticides. It is a consequence of the susceptibility of our overly-simplified, biologically-pauperized agricultural system, which relies on piecemeal pest control approaches like Bt and chemical insecticides rather than ecologically based systems that greatly reduce the opportunities for pests to get a foothold.

So, why not GE AND agroecology ?

Some vocal advocates of GE have acknowledged that we need to use better, ecologically based agriculture practices, but maintain that we should integrate GE into those systems. Such an approach would likely improve the sustainability of GE pest control. But how would it advance truly sustainable agriculture?

In healthy agro-ecosystems, there is usually limited need for these types of pest control, and in most cases, that need can be met through breeding at much less expense than GE. The fact is that GE seed is expensive (because GE research and development is very expensive). And the large seed companies have a near monopoly on this technology, so they can jack up seed prices even further. Why should farmers be saddled with these unnecessary costs when cheaper technologies will work in the large majority of cases?

As I have written before, GE may occasionally have a useful role, and may sometimes provide real benefits. But in a sensible agriculture system it is not clear that it is really needed, or worth the cost.

(Thanks to Chuck Benbrook at the Organic Center for alerting me to the new article on bees and neonicotinoid insecticides)

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  • I have been monitoring this discussion, and I now finally have some time to contribute again.

    Three weeks ago, Doug, you made a clear statement about the nature of reality. Out of curiosity, and charity, I asked you to present your evidence that this is the case, rather than criticize your view at the outset. After three weeks of comments, you have not presented any evidence that the introduction of genetically engineered Bt crops has itself resulted in the widespread use of neonicotinoids, and what has been presented is a mangling of what it means to support an argument in science.

    But to begin, I think you ought to be a little more charitable to the statements of others. Granted, I am not perfect, but I observed a pattern in this discussion where several people including myself chimed in and disagreed with your opinion, and your first response was to just say that we didn’t understand your argument. And you also put words in my mouth and the mouths of others. I understand your argument perfectly, and perhaps I erred by not regurgitating your argument in full to show that my comment does not stem from a misunderstanding. I should exercise more caution when commenting here. When I said ‘direct result’ I was referring to your argument about a shift in pesticide use due to modes of action for pest control, in contrast to the more indirect argument made here about GE crops perpetuating ‘bad farming practices’. That is a more complex and debatable point.

    So let’s get to the claim in question. You said: “But in reality, corn engineered to kill certain insect pests—AKA Bt corn—has mainly resulted in the replacement of one group of chemical insecticides with another.”

    After three weeks, you have only provided one citation for this claim. As Mary has pointed out, the Leslie et al paper does not provide evidence that this is the case. The quote extracted from the paper also does not even discuss neonicotinoid pesticides in specific:
    “Similarly,coleopteran-specific (Cry3-based) transgenic maize may shift insecticide use patterns from at-planting applications of soil insecticides toward seed treatments (Smith et al. 2004).”
    The quote is discussing a potential shift in the manner in which pesticides are applied, from soil-based to seed treatments. Both pyrethroids and neonicotinoids can be applied to the soil and to the seed. And even this claim is not supported by evidence in the paper, but is referring to a 2004 book by Smith et al. This book is available on Google Books, and I cannot find any reference to any terms in, or related to this sentence that supports this statement. (Smith et al. 2004 is used as a reference all over the place so they may have used it as a quick stock reference and they may not have had an actual source for this statement.) Knowing one of the co-authors of the book, there are copies nearby for me to look at, and I have given up trying to source this statement. It also makes little sense to look in a book published in 2004 for information about a trend that would be more recent than that. Besides, the statement you cite does not assert nor support your specific argument – you are misattributing this reference and are left with still no evidence to support your case.
    You said, “But entomologists (cited in my reply to Karl) have also said that the switch to Bt has led to neonic seed treatments.” No, they did not say that about neonicotinoids, see above.
    You said, “The remarks by entomologists that Bt has led to increased use of neonics did not include data on the amounts. They work on these issues, so I have no reason to think they are wrong. So you are challenging their assertion, but have provided nothing to contradict their claim.”
    Science does not operate on authority, but on evidence. Perhaps this is a point on which you and I both differ? A statement by a scientist is not necessarily itself science or scientific, nor does it mean that there is evidence for it. It is not necessary to provide evidence against a claim to question the evidence for the claim – but the widespread use of neonicotinoids on virtually all corn – which you yourself admit – is evidence against this claim. Had history been different, and indeed it has been in other nations that do not grow Bt corn, neonicotinoids may be just as widespread, and in those nations, they are. It is pure sophistry to say that an unsupported claim requires being debunked or it will be accepted as true. It needs to be supported with evidence before it can be accepted as true.
    You said. “Neither the language of the entomologists that I cited and quoted in response to Karl, nor mine (if you read it carefully) says that Bt has “caused” (your word, and Mary’s, not mine)the use of neonics.” This is a strained bit of pedantry. You said “resulted in,” and “led to” which are synonyms for “caused.” Please look it up. And your arguments to defend this statement indicate that you are saying that these traits are responsible, at least somewhat, for the widespread use of neonicotinoids on corn seeds. I cannot take this statement of partial backtracking as an honest analysis of the English language – and I find it rather bizarre because it is both an admission that your reference does not support your argument, and then a denial of basic synonymity. And you are contradicting your previous claim that Leslie et al said “that the switch to Bt has led to neonic seed treatments.”
    Let me repeat, for emphasis. In an attempt to defend this post, you have said two mutually contradictory statements:
    1. “But entomologists (cited in my reply to Karl) have also said that the switch to Bt has led to neonic seed treatments.”
    Which is incompatible with:
    2. “Neither the language of the entomologists that I cited and quoted in response to Karl, nor mine (if you read it carefully) says that Bt has “caused” (your word, and Mary’s, not mine)the use of neonics.”
    No further comment is necessary.
    While looking for evidence for an against this claim, I asked a few experts, including some who have had research published on insecticide use patterns, and one told me this:

    Bt corn targeting corn boring pests can vary on what pests it is effective against depending on the event – hence events like Mon 810 do not include cutworms but I think something like Herculex does. I can’t see how bt corn encourages use of these products, especially as the second generation bt corn and products like herculex actually target some of the pests that the seed treatments will address – if anything the widespread adoption of bt should have a limited positive impact on reducing use some of these products. However, the areas treated and amount of active ingredient of these neonicotinoids in the US has gone up considerably in the last five years so the primary use must be targeting pests that bt does not target.

    The main insecticides that bt took the place of are bifenfrin, chlorpyrifos, fipronil, methyl parathion and permethrin. Whilst use of the actives have fallen they are still used sometimes, even on farms using bt because they control other pests than just the ones that bt controls.

    I am seeking additional information – but it still doesn’t alter the fact that Gurian-Sherman is making it up.

    You said, “This is a blog, after all, not a journal article.” The last time I checked, the standards of evidence for blogs and journal articles, if their authors wish to be taken seriously, are the same. If a claim is unsupported by evidence, it should be corrected or retracted. Typically, bloggers who correct a claim surround it with strikethrough tags so that everyone can see the correction. It is totally up to you whether you ultimately choose to retract your statement, I would just like to remind you that the UCS site says that “The Union of Concerned Scientists is for anyone who believes the facts, not ideology, should drive our decisions.” I hope you will prove this statement correct.

    In the time I spent on this topic, I learned a lot about the complexities of pest management and how Bt corn plus neonicotinoids can sometimes synergize for combating some pests, and sometimes antagonize. I learned that entomologists suggest on their faculty pages and in some papers that high-value seeds may explain the use of neonicotinoids across multiple crop species (as insurance). I would love to spend more time on this topic, as I am not only interested as a plant geneticist and science journalist, but also as a beekeeper who is intimately connected to the lives of his bees. But if I have to do any more of your homework to ensure factual accuracy the UCS may have to pay me, which reminds me, are y’all still looking for a new director? 🙂

    A lot of sweat, blood, and time could have been saved from the very beginning by saying “You know, I don’t have evidence that this is the case, but I think it is certainly possible – I will correct my post to reflect this. I’m glad someone from caught this.” That would have been so much easier, wouldn’t it?

    • Doug Gurian-Sherman

      First, let me reiterate once again the main point of the blog post, which neither you nor Mary have responded to: Vocal advocates of Bt crops have often claimed a substantial reduction of chemical insecticides as one of their major benefits. But this has apparently ignored the increased use of neonicotinoid (and other) insecticidal seed treatments. Or at least, the increased use of neonics and its implications for the environment have not been discussed when this claim is made. We can differ about whether the amount of insecticide is as important as the area covered, toxicity and persistence—where the latter three are problems with neonics. Neonics also do not seem to be as harmful to people or other mammals as some of the other chemical insecticides, which I also acknowledged, and that is good. This main point does not depend on the causality issue that bothers you so much.

      Leaving the issue of causality out for a moment, the bigger point is that Bt is not leading to a more sustainable agriculture in several important ways, as exemplified by the widespread use of neonics, and as noted, for example, by Michael Gray (a corn entomologist) in a recent article. Entomologists like Gray and weed scientists like David Mortensen go further and suggest that these GE crops are actually contributing to the loss of better practices (IPM and IWM). (and before you jump on this, neither I nor Gray nor Mortensen are suggesting that there are no benefits from Bt corn or herbicide resistent crops).

      Because the arguments about sustainability and GE are so important—and often brought up—I think this was an important point to make.

      As for the support that Bt has resulted in (or led to) the seed treatment of corn, of course, a series of papers fleshing this out in detail and with supplied data is more convincing than an unsupported statement made by scientists, even those working in that field. But we also have some confidence that scientists working in a discipline know what they are talking about and tend not to make statements directly relevant to their work that are untrue. In other words, as presumably competent scientists, I assume that it is likely that they have evidence or data to support such statements. You actually seem to tacitly agree with this use of support by feeling it is appropriate to use as support a quote from an anonymous entomologist who makes several assertions without providing any data.

      I was not sidestepping the issue of causality, but answered the question that you posed in a simple and straightforward way. The evidence I was relying on was the statement by Leslie et al. You do not have to accept that as adequate. That’s fine. Leslie et al. could be wrong. I, like you do not have the time to track down every issue to the extent that I would like, so I provided my evidence so that you can decide for yourself in direct response to your request.

      As to a couple aspects of Leslie et al. First, you make a valid point that they do not say specifically that the seed treatments they mention in the quote I used are neonicotinoids. But their paper is specifically about neonics, so from that context, it really does not make a lot of sense that they were talking about pyrethroids. Their statement does not exclude neonics, while the context of the paper makes it clear that they are talking about neonics.

      Second, as I already responded, yes Smith et al. was early in the use of Bt Cry3Bb1. But Leslie et al. is years later. The fact that Leslie et al. cite Smith et al., well after both Cry3Bb1 and neonic seed treatments had become widespread, suggests strongly that (at least Leslie et al. believed) Bt has led to neonic seed treatments. You can argue that this is not adequate support, and we can go around in circles about this forever (actually not, because I am not going to continue responding to this point). If I have time at some point to look into this further, and find more data on it. I will try to let you know. As to your point about me contradicting myself on causality, I do not agree, but you do have a valid point about clarity. Although I have repeatedly said I do not claim that Bt caused the increase in neonics, it is not clear to me exactly what Leslie et al. mean. It is possible that they intend causality, but the term “led” is somewhat ambiguous in that regard.

      Your use of a thesaurus to define the verb “results” is not appropriate, because the definitions of synonyms can be only similar, not identical to each other. And, as well, many words have several accepted definitions. A Thesaurus, in listing synonyms, only considers one of these. A good dictionary is more appropriate.

      My old hardbound edition of “The Random House College Dictionary” has several definitions of the verb form of “result”. One suggests causality (“to proceed or arise as a consequence”) but even here, the definition includes arising from “circumstance,” which suggests indirect causation.

      But more relevant, the second definition is “To terminate or end in a specified manner or thing” This definition says nothing about cause, but emphasizes the ultimate rather than the proximate change. This is the definition I had in mind when I wrote “resulted in”. You asked a legitimate question about my meaning regarding causation, given the imprecision of language. I tried to make clear several times that I did not intend to suggest that Bt caused the increase in neonics, but you simply seem to want to ignore those responses.

      And because the definition I was using does not mean cause, the post is not incorrect, if somewhat ambiguous. So there is no need to strike what I wrote. I think that clarification in the responses is adequate. And I suppose you could have saved your blood, and sweat (you forgot to include tears. I am sorry I have made your life so difficult!).

      So, one more time with emphasis: as I have tried to respond repeatedly, I am not suggesting that Bt has caused or encouraged the use of neonics, but rather Bt has not prevented their use. And this is a response to the often broad statement that Bt has reduced the use of chemical insecticides. I am trying to add some nuance to that discussion by pointing out that by several important measures (but not all) this possible reduction in insecticide use that outspoken supporters of Bt often make may be a distinction with little practical meaning for impact on the environment.

      I am sorry that you seem to find this kind of detailed discussion to be pedantic or an example of sophistry. I think it is a necessary part of good science.

      I spent a lot of time, as I think you would have to agree, responding to you and others. I did not call any of you names or disparage you (as you apparently like to do to me frequently). I don’t believe, for example, that commenting that I thought I was being misunderstood would be construed by a fair-minded person as disrespectful. But if you want to believe that I was doing anything other than trying to respond honestly, that’s for you to decide.

      I do find one aspect of your latest response troubling, and that is your anonymous discussion with your entomologist colleague. If you shared the entire blog post and comments and responses with your colleague, then I simply disagree with his or her conclusion that “I am making it up”. I suspect though, based on this person’s conclusion, that you did not share my multiple attempts to clarify to you and others that I did not intend that Bt causes or encourages the use of neonics. It would have been unprofessional to misrepresent what I said. And if you did, it is not surprising that this entomologist thought that I was “making it up,” given that I did not say that Bt was causing or encouraging the use of neonics.

      I do agree with much of this entomologist’s assessment, although the use of the word “should” in the statement “if anything the widespread adoption of bt should have a limited positive impact on reducing use some of these products.” clearly suggests that this person does not in fact know the details of what is going on with neonic use relative to Bt. Your colleague’s lack of knowledge about the efficacy of Herculex also suggests that he or she is not nearly as knowledgeable about the relevant particulars as you would like us to believe. It seems that even if Bt “should” lead to less neonic use, it apparently isn’t in a meaningful way.

      Finally, I also find it troubling that your entomologist did not have the courtesy to contact me directly before casting aspersions about what I was doing. I am willing and interested in trying to better understand these issues and others’ perspectives. Since I can’t do it myself, please invite that person to contact me directly, now or in the future.

  • Linda J

    Recent reports in scientific literature indicate that there is growing resistance to Bt engineered corn, the pests to be controlled (root eaters? I don’t recall) are no longer being killed. The problem is that all insects seem to become less susceptible to insecticides they are exposed to often, and all insects in the fields are exposed to the genetic modifications put in the crop. I’m old. DDT killed insects wonderfully well, but lost efficacy quickly (killed birds, too, but nevermind..). Malathion worked for a while. Et cetera.

  • George

    Doug: I agree with Mary. I don’t beleive that she has failed to back anything up- she’s not asserting that neonics havn’t been associated with an increased use of Bt. In fact it would seem they have, however, the point is that there is no evidence for this being a causitive relationship, as is bakced up by the point that neonics are used as seed treatment in many, non-GM as well as GM crops. You yourself are admitting that Bt is very effective and has led to less pesticide use, pound/acre wise. I would assert that this is because farmers no longer need to target lepidopterans, as you yourself have stated. Rather than neonics replacing these pesticides, they are used and would be used along side Bt or any alternative to Bt since Bt can’t kill the pests neonics do. It seems to me surely that the increased use of neonics probably has more to do with their recent marketing (80’s I beleive, if you can call that recent!), and the increased cultivation of corn in the US. Corn, GM or not, seems to attract the use of neonics. It seems to me that you are making some kind of pseudoscientific association between neonics and Bt to make it sound somehow like Bt crops have led to increased pesticide use, when in fact they have led to the use of less pesticides which combat moths, but continue to use pesticides to combat other pests. Presumably a net reduction in pesticide use. I just don’t think you’re making a point against GM- you’re making a point against neonics.

    • Doug Gurian-Sherman

      George, Thanks for the comment. I have already answered several of your points in responses to Karl or Mary, and you and Mary have not really addressed them. First and foremost, the clear context of this blog post is a response to the frequent claim by vocal proponents of GE that Bt corn has led to a meaningful (e.g. less harm) reduction in insecticides use. The substitution of neonics for much of the previous use of chemical insecticides on corn calls that claim into question. As I wrote in the first sentence of the second paragraph of the post: “But in reality, corn engineered to kill certain insect pests—AKA Bt corn—has mainly resulted in the replacement of one group of chemical insecticides with another.” Note the word “mainly”–there is no attempt here to mislead anyone–I did not say neonics entirely replaced other insecticides. Note also the words “resulted in”. In other words, the result of adopting Bt has been, largely (not entirely) a substitution of one group of insecticides for another. This is exactly what has happened. Because neonics are a seed treatment, they would be expected to be used at a lower rate per acre than many soil treatments or sprays. But probably more relevant to the environment are the acres treated, the relative toxicity of the different insecticides, and their persistence. It is acres treated, and especially the persistence, that is disconcerting about neonics. Most of the insecticides that it replaced, as well as the neonics themselves, are highly toxic to many species of insects and related organisms.I have also responded to the causality issues in response to Karl’s question. Neither the language of the entomologists that I cited and quoted in response to Karl, nor mine (if you read it carefully) says that Bt has “caused” (your word, and Mary’s, not mine)the use of neonics. But that, as I have said several times, is not my point, and not the main point of the blog.

      But you also are incorrect factually in several of your points. First, Bt has not eliminated lepidopteran (moth) problems. It is effective against several important leps, but there are several others that it is not very effective against.

      More importantly, you incorrectly say “Rather than neonics replacing these pesticides, they are used and would be used along side Bt or any alternative to Bt since Bt can’t kill the pests neonics do.” Neonics would not be used in “any alternative” to Bt. Organic and other similar sustainable agricultural practices would not use neonics, and can do so with low insect damage, and yields as high as the GE-industrial agriculture paradigm, as demonstrated by a lot of peer-reviewed research.Some of these methods allow the use of pesticides, but need them only sparingly because the cropping and crop management systems keep pest pressures very low. And that is another main point, perhaps the most important one, of this blog post–that GE is largely part of the same non-sustainable cropping system that we have now.

      • George

        Okay first of all I recognise that Bt doesn’t deal with all lepidopteran pests, of course diamond back moth would be an example (I never said it has eliminated them, I said farmers felt they did not have to deal with them with their previous pesticides). However my point was that Bt is now used instead of pesticides which were used to target leps beforehand, which is true, am I right? And when I was refering to alternatives to Bt which neonics would be used along side with, I wasn’t refering to organic agriculture. I was refering to the pesticides which farmers no longer use because of Bt. The points with which I am still struggling are that firstly, as in this quote “But those who tout the benefits of GE fail to mention that today virtually all corn seed is treated instead with chemical insecticides called neonicotinoids to ward off several corn insects not well controlled by Bt toxins”, note the word ‘instead’; you seem to be implying although with the use of the words ‘mainly’ and ‘resulted in’, that neonics have actually replaced previously used pesticides in Bt crops. Which would appear not to be the case. Secondly, if you appreciate that neonicotinoids are used for all crops, GM or not why is it that you’re fabricating this link between GM maize and neonics? Simply because more Bt maize is being grown that does not dictate that it is has ‘resulted in’ increased neonic use- which is what you are implying. I know you don’t like my use of the word cause, but you are suggesting causation. By this reasoning, you should not be arguing against Bt corn, but simply against the use of neonicotinoids. If you wanted to argue against non-organic monoculture and neonics then that would be a different matter. I don’t see why, without the use of neonicotinoids, even in organic agriculture, one shouldn’t see the (undoudbtedly) pesticide reducing effects of Bt as beneficial provided other, harmful pesticides aren’t used. Do you not agree that the effects of Bt corn can only be beneficial (in its conventional monocultural agro-ecosystem), considering that many other crops also attract the use of neonics? Surely Bt maize is comparably more environmentally friendly than using neonics and previous chemicals? Although you may be right that this has not necessarily led to less harm being done by pesticides, it has certainly led to less pesticide use (and less harms specific to the pesticides which aren’t being used) and what I am arguing is that if neonics are harmful they should be treated as a separate issue. I hope you understand my concerns with your assertions, don’t feel however that I disagree with you that an increase in neonic use is not a good thing!

      • Doug Gurian-Sherman

        George, Yes, Bt is now used instead of several other insecticides to control lepidopteran pests and rootworm (Coleoptera). However, those previous insecticides were broad spectrum insect toxins, such as synthetic pyrethroids, so they controlled a number of secondary pests not controlled by any Bt. Most of these are Coleoptera. The Bts are narrower spectrum toxins than the chemical insecticides. That’s a good thing in and of itself. But neonics that have replaced the previous soil applied or sprayed broad spectrum insecticides are also pretty broad spectrum insecticides. And yes, as far as I know, the neonics are used, at least to a significant extent, instead of those previous broad spectrum insecticides, or as Leslie et al. (2009) wrote, Bt may “shift” the use from soil applied or sprayed insecticides to seed treatments (neonics)(”Similarly,coleopteran-specific (Cry3-based) transgenic maize may shift insecticide use patterns from at-planting applications of soil insecticides toward seed treatments (Smith et al. 2004).”)I think “shift” means essentially the same thing as “instead of”. I realize that Leslie et al. is citing Smith, who said “may” shift, but that is clearly just a figure of speech, because Leslie et al. later cite Smith as saying that all Bt rootworm corn does, in fact, undergo seed treatment. So, as I said to Karl, I am relying on the expertise of those entomologists when I say that Bt has “mainly” resulted in the replacement of one set of chemical insecticides for another. The point is not that Bt has made things worse (it may have for some insects like bees), but that it has also not made things much better for the environment. I never focused, by the way, on Lepidoptera, except in response to Mary and you. I clearly was talking about both leps (corn borer) and Coleoptera (rootworm). I also realize that I did not link this Leslie et al (2009) article in my post (I linked their 2010 article about neonic effects on non–target beetles). This is a blog, after all, not a journal article. But I clarified this in response to Karl’s comment.

        We will have to differ on whether the relative amounts of pesticides is more or less important then their relative toxicity or persistence. I would argue that toxicity and persistence are generally more important. But in any case, given the combination of extremely widespread use (virtually all corn seed treated) and persistence, I think it is hard to argue that there is more than minimal (at best) advantage to the environment from the current use of neonics compared to the previous use of soil applied or sprayed insecticides (neonics may be less harmful to people, which is a good thing). Supporters of GE often have downplayed the increased use of glyphosate herbicide due to resistant weeds because it is claimed to be less toxic and less persistent than herbicides that it replaced.

        But this gets back to the two actual main points of the post, which neither you nor Mary seem to want to address, despite my having mentioned it several times. And that is 1) that vocal supporters of GE have often touted as an important environmental benefit of GE that Bt has resulted in less insecticides use. The blog post is partly a response to that claim, which while it may be nominally true (in terms of amount of insecticide), is functionally probably not true ((in terms of environmental impact), and 2) proponents of GE often talk about how it is leading toward greater sustainability in agriculture. But as the quote from Michael Gary illustrates, that does not seem to be the case for Bt. So, while Bt does provide some real benefits, which i acknowledge, it is not nearly all it is cracked up to be in terms of environmental impact or sustainable agriculture.

        And this leads me to another point that you make, which is about organic farming. I suspected that you were confining your remarks to current industrial agricultural systems. But in my opinion, that is a false dichotomy. Why not consider organic, or, more broadly other sustainable ag systems like low-external-input systems? I consider these systems better in many respects than current industrial monocultures, with or without Bt. So why should they not be a standard of comparison? Of course, the GE and pesticide companies would love to keep the discussion confined to different approaches to industrial ag, for which they can sell their products.

        As to harm, you assume that without Bt, farmers would be using their previous insecticides AND neonics. But that is not at all clear, and probably not generally true, since, as I (and Leslie et al) argue, neonics have largely substituted for those previous broad spectrum insecticides. Farmers would mostly have used one or the other of the insecticides, not all of them. They would only have added neonics if it gave them substantial (economic) additional control, and I have never heard that would be the case.

        Finally, on the negative side, our over-reliance on GE, as Michael Gray argues, has discouraged more ecologically-based insect management practices. So to the extent that is true, Bt has in a sense actually made farming less sustainable. This is a “big picture” way of looking at this, but that is just the point–we need to expand the way we think of this issue.

  • I regret to say, being a life-long gardener, that I did not see a single honey bee in the garden this summer (2011)! The pesticide-bee survival connection is worth great emphasis in letters to our legislators. However, since they usually don’t understand the evidence, they dismiss the connection. Anything you can do to disseminate the truth in these matters to these folks would be helpful. Keep up the good work!

  • There are almost no GMO cultivated in Europe (including Switzerland where there is a total GMO-moratorium)and a lot of organic farming, nevertheless bees are not in better shape. The fuss about GMO cultivation affecting health of bee colonies is just miss-information (or you are just wrongly interpreting available data).

    • Portulan, you seem to misunderstand what I have written. I have not said that GE has directly affected bees, as you imply, but rather that the use of Bt has contributed to the increased use of neonic seed treatments, which looks like it is harming bees (whether that harm is a contribution to colony collapse disorder, or other mortality of bees).

      It is unclear to me whether bee deaths in Europe are as great as in the US, you seem to be merely asserting that. But yes there are substantial bee deaths in Europe, which also has a lot of the same industrial ag as the US, which Bt and other GE crops are largely a part of here. There are also several other problems with honey bees, including vaaroa mites, pathogenic fungi, and so on.

      But you are ignoring the extensive direct evidence that neonic seed treatments are involved in bee deaths in the US. And you are also ignoring other field data (some of which I cite) that neonics are also harming other insects important for controlling pest insects.

  • It is so good to see UCS concerned about the pollinators. I am a relatively new beekeeper, living it what Rowan Jacobsen aptly decribed in his book “Fruitless Fall” as the ‘corn desert’ of Nebraska.
    I am also a veterinarian and have extensive experience in the vaccine world. I know immunosuppression when I see it, and it is the delayed lethal effect of the neonicotinoids. See Henk Tennekes work, a toxicologist from the Netherlands. He says it so well, the neonics are destroying the web of life.
    Another side effect of the neonics on corn: The insects that chew into the stalks for food or shelter are vanishing, the ‘stover’ no longer breaks down in a season or two. Farmers are adding a shredder option on the back of the harvesting combines to reduce particle size and hasten decomposition. This ‘option’ adds the price of a midsize car to the combine. A worse option is baling the stover and selling off for livestock roughage. This depletes the soil of organic matter and increases the dependence on synthetic fertilizer. The spiral decends!

    • Jolly Green One

      Easy to advocate for insect-chewed plants when it isn’t your corn that’s infested. You claim to be a veterinarian — do you advocate for dogs and cats to be kept thoroughly flea infested? No thanks, “doc”. Our family will take our advice from real farmers and real animal doctors.

  • Anthony Samsel

    Working in the interest of Public Health and the environment, I find it appalling that in the twenty first century we continue to release chemicals and biologicals to the environment with inadequate, unbiased third party testing. Just because a Corporation spends millions of dollars creating a product and wants a return on their investment should not be a prerequisite to the approval process. The revolving door policy in Washington which allows former Corporate employees key agency positions in the approval process needs to end. It is apparent that members of the Federal Government and Agencies responsible for oversight are more interested in their political paramours and election revenue streams than the health and safety of people and our planet.

    Politicians do not possess an understanding of Agriculture, pollination and sustainability of natural biologic systems. Neither do they posses an understanding of the adverse health effects from pesticides, chemicals and Genetically Engineered Food and the threat these foods pose to humans, animals and diverse ecosystems.

    Clothianidin is not the only systemic pesticide killing bees, all systemic pesticides kill bees and Bayer systemics are the largest killer of bees and insects on the planet. Temik and Imidachloprid are the more popular systemic pesticides used in agriculture around the world. They are the most widely used, are toxic to bees and you. They are commonly found in your favorite foods if you are not eating a totally organic diet.

    The systemic pesticides Temik and Imidacloprid used by farmers are produced and sold by BAYER and TEMIK has been the first choice followed by IMIDACLOPRID. Production of Temik will cease by Dec. 31, 2014, use in the US will end by August 2018. Temik originally developed by DUPONT is an aldicarb and in humans causes weakness, blurred vision, headache, nausea, tearing, sweating, and tremors. It can paralyze the respiratory system, it is bio-cumulative and in higher doses is fatal.

    Imadacloprid systemic insecticide from BAYER is a major cause of colony collapse world wide. It is one of the most widely used pesticides on the planet with distribution in over 100 countries. I have had personal experience using systemics on a commercial scale having been the owner of an Agricultural Corporation in the Northeast USA. In the 1990’s on two separate occasions we had complete colony collapse of our bees. The first incident loosing over a half a million bees that foraged on two acres of potted perennials which were treated with Imadacloprid. The second time I lost seven hives to a neighbors Grub control treated clover lawn. After seeing the total collapse of our hives we stopped using Imadacloprid.

    Imidacloprid is a neonicotinoid insecticide, exposure symptoms include from vomiting, abdominal pain, headache and diarrhea, (mild poisoning) to respiratory arrest and fatal ventricular fibrillation. Co-ingestions with especially organophosphate are more hazardous than imidacloprid ingestion alone. So if you have eaten any other food that might have contained an organophosphate you could be the victim of synergistic poisoning which is greater than either pesticide alone. Imidacloprid is also used by veterinarians on dogs and cats, sold to the public as Advantage flea and tick medication. Imidacloprid is also a neurotoxin.

    Imidacloprid renders all parts of the plant toxic including the plants pollen and kills countless numbers of bees annually. It is sold to homeowners in lawn care products to kill grubs as Grubex (Scott products & others) and as a systemic houseplant insecticide. It’s one of the most toxic insecticides to honeybees with a contact acute LD50 = 0.078 ug a.i./bee and an acute oral LD50 = 0.0039 ug a.i./bee.

    Imidacloprid, has the largest application amount of neonicotinoid insecticide in the world, 20,000 thousand tons. It is the pesticide of choice in over 100 countries. In Florida, farmers apply Imidacloprid on crops at an average rate ranging from 0.17 to 0.27 pounds per acre. With 20,000 tons currently being produced annually for agriculture that’s enough Imidacloprid to contaminate between 160-235 million acres of food cropland.

    This pesticide does not wash off, and it does not peel off. It is used on coffee, stone fruits like peaches, oranges and citrus, peanuts, bananas, grapes, lettuce, eggplant, tomatoes, beets, cabbage, Brassicas, cucumbers, melons, potatoes, rice, hops, grains and other food crops, cotton and ornamental plants and trees. It is absorbed into the fruits and vegetables making them toxic to insects and YOU! It affects the Thyroid gland and in birds causes soft weak shells like the effects from DDT which Rachel Carson wrote about in ‘Silent Spring’.

    Decisions involving genetic engineering have and continue to ignore the ‘ Precautionary Principle.’
    Horizontal Gene Transfer and recombination of Transgenic DNA is inherently designed to jump into Genomes sometimes through virus or Bacterial Plasmids. This fact makes Transgenic DNA different and more dangerous than naturally occurring DNA. Agrobacterium tumefaciens and Cauliflower Mosaic Virus (CaMV) are two major vectors for transferring DNA creating transgenic plants. Agrobacterium not only transfers its genes to plant cells it can also accept genes from plant cells by the process of retrotransfer. Agrobacterium has a known ability to attach and Genetically change several Human cell lines making it a major concern in the spread and creation of new pathogens resistant to drugs and antibiotics.

    I would avoid honey made by bees foraging on Genetically Engineered crops. Bees carry Genetically Engineered pollen corrupting natural plant species and even corrupt themselves and the honey they produce in the process. Genes from GE food and toxins released from genetically engineered bacteria like Bt are of concern as they may damage and thin the lining of your gut and colon, lead to sterility and yet to be identified other debilitating diseases.

    Plants including grasses, and animal forage crops, fruits, vegetables, shrubs, trees, yeast, bacteria, fish, birds and animals are all being Genetically Engineered. Pollen, spores and seed can travel thousands of miles on upper-level winds and birds spreading unwanted genetics far and wide.

    Anthony Samsel was an environmental consultant at Arthur D. Little, Cambridge, MA on many US Coast Guard, EPA, and Army Corps of Engineers environmental projects and impact statements. He is a member of the Collaborative on Health and the Environment and the Union of Concerned Scientists

  • “But in reality, corn engineered to kill certain insect pests—AKA Bt corn—has mainly resulted in the replacement of one group of chemical insecticides with another.”

    What is your source for this statement? I have frequently read the claim on blogs that genetic engineering and seed treatments are linked, however, this has not gone beyond a simple guilt-by-association claim. You are saying that these seed treatments are a direct result of controlling corn borers and rootworms with Bt crops. To demonstrate this, it takes more than saying few seeds were treated with neonicotinoids prior to the existence of Bt crops, because this is a new trend across the board. Soybeans and canola are also frequently treated with these kinds of pesticides, and there are no Bt versions of them. (although that may change soon with Brazil I hear) Also, non-Bt varieties of corn are also frequently treated with these pesticides. Melons, lettuce, timber, rice, potatoes, etc. Clearly, genetic engineering does not explain their use in these crops, so how does it explain use in corn?

    So could you provide the evidence that backs up your specific claim that Bt GE crops has resulted in the use of neonicotinoids? So far, no evidence has been presented for this claim.

    • Doug Gurian-Sherman

      Karl, Thanks for the good question. First, you are misinterpreting, in part, what I have written. To the extent that Bt crops have led directly to an increase in neonicotinoid seed treatments, it is probably not (as far as I know) because Bt controls corn borer and rootworm. I did not write that. Rather, the problem is that Bt does not control (or not well in some cases) other insects that would have experienced some control from soil applied insecticides for rootworm or other insect pests.

      And you are correct, as I acknowledge, it is being used on other crops as well. I am well aware that many of these crops do not contain Bt. So I agree, to the extent that Bt is leading to these seed treatments, it is clearly not the only reason.

      But you also seem to be missing the bigger point, from the lead sentence, that regardless of the exact causal linkage, Bt has probably not reduced insecticide use in a meaningful way, as vocal advocates for GE often claim (I don’t know yet whether the amount of insecticide used is less now, but the acres treated do not seem to be less. And this may be more important for environmental impact. Especially because neonics can be quite persistent). And even more importantly, one of the main reasons these seed treatments are used is because the cropping systems are not ecologically diverse. GE crops are not leading, so far, to better agronomic practices, so they lead to substitution of different insecticides to limit damage from insect pests. So GE so far is just an extension of bad farming practices.

      As far as support that Bt has actually contributed to increased seed treatments, I relied on the authority of Leslie et al. 2009. Environ. Entomol. 38(3): 935-943.”Similarly,coleopteran-specifc (Cry3-based) transgenic maize may shift insecticide use patterns from at-planting applications of soil insecticides toward seed treatments (Smith et al. 2004).” In any case, this is not the main point.

      • Mary

        So you are saying you are baiting-and-switching the argument? It’s not about GMOs, but you wanted people to think so?

        The paper said nothing of the sort. And in fact they also list other crops treated with this seed treatment, including wheat–and I’m certain there’s no Bt wheat right now.

        Do they also do this treatment in Europe, where there are few GMOs? Because I know there are bee issues there there, also possibly linked to neonicotinoid. So that would be unlinked largely to GMOs. Right? Oh–look, evidence that Europe is using them:

        So it’s not about GMOs. Uh huh.

      • Mary, There are likely several reasons why neonics are being used, as I said in my post, and yes, once again, they are also being used in non-Bt crops. But entomologists (cited in my reply to Karl) have also said that the switch to Bt has led to neonic seed treatments. You have not addressed that. It is simplistic to suggest that there should be only one reason why these insecticides are used. Overall, though, it is the ecologically bad cropping practices that GE is a part of that creates the need for this heavy use of insecticides, as other entomologists that I cite have said..

        Your point about the recent paper saying nothing (one way or another) about GE crops and neonics use ignores what other papers by entomologists (that I cited in response to Karl’s comment) have said, which do implicate Bt crops as one of the reasons these seed treatments are being used.

        Your point that neonics have also been used in Europe is addressed above–there are several reasons why neonics are used, Bt being one of them. But as your link points out, many of these uses have been banned in Europe, and some of the other uses that are allowed are different–spray applications.

      • Mary

        I don’t see anything in that paper provides numbers about the rates of treatment on Bt vs conventional seeds and any increase related to it. Can you cite the specific data for that–with the actual numbers?

        You also seem to suggest that the reason that Bt fails is because it doesn’t solve every pest problem. But it’s not designed to do that. You sound like an anti-vaxxer on the HPV vaccine, moving the goalpoasts. I’m sorry that it doesn’t kill enough to make you happy. But why do I suspect if there was another mechanism cloned in you’d criticize that as well….

      • The remarks by entomologists that Bt has led to increased use of neonics did not include data on the amounts. They work on these issues, so I have no reason to think they are wrong. So you are challenging their assertion, but have provided nothing to contradict their claim.

        Just to alleviate your concerns, I am a big supporter of vaccines. Evolution is as certain as anything can be, and so is climate change and the substantial contribution to it from human activities. I am not as certain about String Theory, but the maths’ ability to unify quantum mechanics and quantum gravity is impressive, although the lack of experimental confirmation is a bit troubling (but how about that new LHC data suggesting the existence of the Higgs!!). Seriously, though, I am happy with the spectrum of insects that Bt can control. Too broad a control mechanism could lead to higher direct harm to non-target organisms. Bt has a lot of value to farmers working in the current predominant, largely monoculture, midwestern agriculture system. When they have high infestations of corn borer or rootworm, Bt reduces losses. They probably also save farmers time (until resistance occurs). But as I said early in my original post, vocal supporters of GE claim that it substantially reduces insecticide use in corn, and I argue that this doesn’t really seem to be the case. It might result in somewhat less pounds of insecticide, but it does not seem like it results in less acres treated, or meaningfully less harm to non-target organisms. And since neonics are pretty persistent, they are a particular concern.

        So, again, I do not have a problem with the efficacy of Bt. It is generally very effective. But in terms of benefits related to pesticide use, that seems a dubious claim. And, while the industry and some others like to argue that GE is better for sustainability, in the case of Bt corn, that is questionable and marginal, if it is really a benefit at all. It seems to just further encourage the kind of biologically bad agriculture we have now. It certainly is not leading to a fundamentally more sustainable agriculture, and according to very knowledgeable entomologists like Mike Gray, it may be contributing to less sustainability (i.e. IPM).

      • Mary

        This is your claim: “But in reality, corn engineered to kill certain insect pests—AKA Bt corn—has mainly resulted in the replacement of one group of chemical insecticides with another.” It is not substantiated. That’s the point.

        And the tactic you are using is just like anti-vaxxers. Misrepresenting the work in this paper, plus making demands on tools that they weren’t designed for. It’s a disingenuous strategy.

        Is this headline yours: “Genetically Engineered Crops in the Real World – Bt Corn, Insecticide Use, and Honey Bees”? Or are you going to claim you didn’t have anything to do with that, like Ari did at the Atlantic?

  • jacobus

    The neonicotinoids were banned in Italy and their bees rebounded the very next year. That’s pretty convincing to me. But the vast majority of GE crop seeds deployed out there are “Roundup Ready!” so they can be drowned in glyphosate. That essentially calls the “fewer chemicals” claim a lie, and it is the act of the GE firm Monsanto itself.