DDT, Junk Science, Malaria, and insecticide resistance

Last week, I outlined four specious claims made by those attacking Rachel Carson and promoting DDT. (Visit that post to see links to articles in various national media outlets that swallowed these claims without any critical inspection. Sigh.)

Today, I’ll deal with their third bogus claim:

3. Mosquito resistance is not an issue.Resistance” is not an issue since this mostly takes the form of avoidance and keeping mosquitoes away from human prey is the intended object anyway” (junkscience.com)

This is the heart of my objection to their “give us DDT and we’ll cure malaria” campaign. I’m not anti-pesticide or anti-DDT, I’m pro-IPM (Integrated Pest Management). IPM is a way of evaluating each pest situation individually, and making evidence-based choices for treatment.

My issue with the DDT fetishists, aside from their completely unwarranted attacks on Rachel Carson, is that they choose tactics FIRST, rather than evaluating each individual situation. This is like randomly prescribing drugs for a patient without any diagnosis. (Viagra for a bladder infection–bad idea.)

Not taking an IPM approach is a recipe for disaster–and this is how we get into insecticide resistance. I’ll start with some historic background, a brief discussion of how DDT works (and stops working when resistance evolves), and then get into the DDT evidence. It’s a complicated story, because resistance to DDT arose in several different ways.

The historic background

IPM originally was developed in the 50′s, as a response to insecticide resistance. If you look at some of the early papers from the late 40′s and 50′s, the optimism for DDT and its chemical relatives was incredibly high. It seemed like we could cure and kill anything. And it did work wonderfully…for a while.
For an excellent comprehensive review of the optimistic “veni, vidi, vici” attitude of the times, see “Golden Age of Insecticide Research” (1).History of Resistance (Futuyma)

Two major problems quickly developed with synthetic pesticides: first, insects that had the metabolic ability to detoxify pesticides were quickly selected for and increased in the population. Classic Darwinian selection.

Second, “natural enemies,” or parasites and predators that acted as natural brakes on insect populations, were killed along with the mosquitoes. Oops.

To make things even worse, once an insect species becomes resistant to one pesticide, they often have “cross resistance” to other, newer pesticides. Note the rate of change increasing over time in this graph–that’s cross resistance at work.

Insect resistance happens because natural selection acts on rare, random mutations that happen to protect against harmful chemicals. Suddenly, these mutations are of value, and increase an insect’s chances of reproduction–and spreading that resistance in the population. From Doug Futuyma, a leading evolutionary biologist:

“The most effective strategy, based both on evolutionary models and on evidence, is to provide pest species with pesticide-free “refuges” in which susceptible genotypes can reproduce, thus preventing resistant genotypes from taking over. The intuitively appealing opposite strategy – trying to overwhelm the insect population with “saturation bombing” – simply hastens the evolution of resistance, because it increases the strength of natural selection.” (emphasis mine)

This is my primary objection to the pro-DDT folks–they don’t seem to have ANY understanding of resistance management, or natural selection. They present DDT as a cure-all solution. This is a sure-fire way to end up on the “pesticide treadmill“, and risks loosing the ability to use other pesticides to control malaria.

How do pesticides work–and stop working–through resistance?

Most pesticides are nerve poisons, although each different group has specific targets. (How pesticides work is a fascinating topic, and could have made my deadly dull organic chemistry classes a lot more lively, had we just discussed how to poison one another!)

Because books can (and have) been written about the many ways in which pesticides work, I’ll stick to just DDT’s mechanisms. Of necessity, I will grossly over-simplify for the molecular biology impaired :)

DDT (and pyrethroids) blocks Sodium ion flow (alternate animation) across a nerve membrane. If the nerve can’t depolarize, the cell (and animal) is effectively paralyzed.

There have been 3 general modes of resistance to DDT:

1. Resistance due to metabolic detoxification

Insects with enzyme variations that can detoxify DDT quickly increase in a population through natural selection. Normal (unexposed to DDT) insect populations may also have an existing low level of these detoxifying enzymes, and then be selected for “over-expression”, where they overproduce the enzyme in enough quantities to quickly neutralize DDT.

Because these papers tend to be pretty heavy going for non-molecular biologists, I’ll just highlight one enzyme: Glutathione S-Transferase. This enzyme converts DDT to a non-toxic product. Do a Google search for this enzyme and “DDT” and you’ll get a sense of the volume of literature out there.

2. “kdr” (knockdown resistance)
This is the most well studied resistance mode in malarial mosquitoes. It is caused by a reduction in the sensitivity of the insect nervous system to the insecticide. For the most part, point mutations in sodium channel genes are the primary cause of knockdown resistance–in other words, single amino acid changes, the type of mistake that can quite easily happen in the DNA replication process. Not surprisingly, there are many different forms of kdr resistance, involving a slight change here or there on the ion gate gene sequence.

The literature is full of papers documenting kdr resistance across the globe–for brevity, I’ll simply send you to Google again, and tell you to search “DDT kdr”

3. Behavioral Resistance

This is where we come back to the junkscience.com misconceptions. They ignored the two major physiological resistance mechanisms I mentioned above, and focused on the “repellent” activities of DDT. This is a complex topic, and they have misunderstood it completely.

It’s important in an IPM strategy to know your pest–where do mosquitoes rest when they aren’t feeding? When do they feed? Many of the mosquito species important in malaria transmission are called “endophillic”; that’s a fancy way of saying they like to hang out indoors, in dark, enclosed areas. Like houses. So, spraying the interior walls of homes with DDT could be very effective for these species.

Except… not all mosquito species rest inside homes (Culex or Aedes do not, for example), so in areas where these species are the major vector, interior sprays won’t work.

The Junkscience people are partly correct; DDT does have a long lasting “irritancy” effect, where it provides a strong stimulation to take off and fly, making mosquitoes exit a treated house.

That sounds good, but this “bite and run” behavior means mosquitoes don’t rest on the treated walls. If they don’t rest on the inside wall, they don’t come in contact with the insecticide. The mozzies don’t die; and people are still bitten. There is abundant evidence from different parts of the world that DDT use created natural selection on endophillic species (usu. Anopheles), and resulted in altered behavior.

This was first described decades ago in Tanzania and Indonesia (4, 5). Some mosquitoes shifted their behavior to rest in bushes, or on the outsides of homes. Obviously, mosquitoes that have the “bite and run” trait will quickly increase in the population–since mosquitoes resting within a treated house are dead, and corpses rarely breed :)

In some cases, DDT irritancy can work for you–in this study, they conclude DDT will reduce mosquito/human contact. But they came to that conclusion after careful testing–not because of a political agenda. Note that the different species in the study cited had different responses to the DDT, as well. It’s not a one-size-fits-all solution.

Behavioral resistance continues to be a problem, and assessing the behavioral traits of a local population is an important first step to choosing an appropriate control.

Cross resistance

This isn’t a mechanism of resistance, per se, but an unfortunate consequence. Sure, we can nuke mosquitoes with DDT. But we risk losing our chance to control insects with other pesticides if we overdo it with DDT.

In a recent study (3), malarial mosquitoes selected for DDT resistance also developed very high levels of cross-resistance to other pesticides–including malathion, permethrin, and bendiocarb. (Malathion is commonly sprayed in the US for mosquitoes.)

Unfortunately, the kdr trait confers cross-resistance to both the rapid paralytic and lethal actions of all known pyrethroids, as well as the pyrethrins and DDT(2). Most alarming, in field tests where the kdr resistance to DDT is present, the ability of pyrethroid-impregnated bed nets to prevent biting at night was compromised (“major loss of efficacy”).

Conclusion:

I think it’s fair to say that the claim pro-DDT folks made, as outlined in my original post that “Mosquito resistance is not an issue” is well and truly dead.

I’ll close with a quote from one of my favorite authors, who is an entomologist with waaaaay more ‘street cred’ than me (she’s in the National Academy):

“The truth is that DDT is neither superhero nor supervillain — it’s just a tool. And if entomologists have learned anything in the last half-century of dealing with the million-plus species of insects in the world, it’s that there is no such thing as an all-purpose weapon when it comes to pest management. DDT may be useful in controlling malaria in some places in Africa, but it’s essential to determine whether target populations are resistant; if they are, then no amount of DDT will be effective….

Overselling a chemical’s capacity to solve a problem can do irretrievable harm not only by raising false hopes but by delaying the use of more effective long-term methods. So let’s drop the hyperbole and overblown rhetoric — it’s not what Africa needs. What’s needed is a recognition of the problem’s complexity and a willingness to use every available weapon to fight disease in an informed and rational way.”

Amen, sister.

Additional reading:

Off-line references:

1. Casida & Quistad, 1998. Golden Age of Insecticide Research: Past, Present, or Future? Annual Review of Entomology 43: 1-16.

2. Soderlund, DM, Knipple, DC. 2003. The molecular biology of knockdown resistance to pyrethroid insecticides.
INSECT BIOCHEM MOLEC 33 (6): 563-577 doi:10.1016/S0965-1748(03)00023-7

3. T. S. MATAMBO, et al. 2007.Insecticide resistance in the malarial mosquito Anopheles arabiensis and association with the kdr mutation . Medical and Veterinary Entomology 21 (1), 97–102. doi:10.1111/j.1365-2915.2007.00671.x

4. Gerold J.L. 1977. Evaluation of some parameters of house-leaving behaviour of Anopheles gambinae Acta Leiden. 45: 79-90.

5. Sundavaraman S. 1958. The behaviour of A. sundaicus in relation to the application of residual insecticides in Tjilatjap, Indonesia. Ind. J. Malariol. 12: 129-156.

Hemingway & Ranson. 2000. Insecticide resistance in Insect Vectors of Human Disease. Annual Review of Entomology 45: 371-391.

41 thoughts on “DDT, Junk Science, Malaria, and insecticide resistance

  1. “The most effective strategy, based both on evolutionary models and on evidence, is to provide pest species with pesticide-free “refuges” in which susceptible genotypes can reproduce, thus preventing resistant genotypes from taking over. ”

    Can you explain this? My only guess for why it would work is that resistance comes at a considerable cost for the individual pest that has it, so the non-resistant individuals can outcompete resistant ones in the refuges. And if that’s true, the level of non-resistance in the general population will only be high if the amount of pesticide use is low. So yes, you’ve stopped complete resistance, but how much does it matter?

    Maybe I’ve got it wrong…

  2. Remember about “pesticide-free refuges” — the, what, 99+ percent of insects that are neutral or helpful to agriculture also benefit, as do the other insects and birds and other animals that prey on the insects.

  3. Brian, since our host’s traveling: put
    cost of pesticide resistance
    into Google, the first page of hits includes articles on exactly the question you ask; you’re right. As long as there’s no widespread spraying, resistance genes aren’t “worth the cost” to the organism; what counts is number of grandchildren.

  4. Bug Girl.

    Don’t be listening to Lambert.

    He’s a DDT-Holocaust-Denier.

    Now he wants to kill them all off with energy-deprivation on account of his pathological Malthusian fears.

    THERE’S ALMOST NO-ONE OUT THERE WHO DOESN’T THINK THE SKEETERS CAN DEVELOP RESISTANCE.

    This is a Lambert Myth.

    What these leftists like Lambert and Quiggin do is that after their leftist forbears have killed off like 50 million black kids minimum through stiff-arming people not to kill the mosquitoes….

    … After that what happens is that they start claiming that the anti-chemical Lamberting SAVED LIVES.

    You see in this nazi view of the situation not only have they not created a great tragedy…. But they’ve saved millions of lives due to less resistance.

    Now this is a plainly ridiculous history and a buggered view of the process wherein these critters get resistance…..

    … So the next step that these Malthusian refugees from the fall of the Soviet Union head to is to say that……..

    …… THEIR OPPOSITION ARE CREATIONISTS AND DO NOT BELIEVE IN SKEETER-RESISTANCE.

    Its unbelievable what that facist dwarf will try on.

    We are upset that we’ve been tarnished by leftists who have blithely murdered millions of kids die in this way and are now covering up and trying to go for a repeat performance with this global warming unscience.

    But this evil white dwarf…. running ahead is throwing all these holocaust-denial landmines in the way.

    Now he’s saying that the only people who believe that all these kids died are creationists.

    But the fact is they all did die and are dying still and thats got nothing to do with it.

    You don’t know these hardcore marxists or ex-marxists.

    They just keep spewing out these disinformation bombs.

    I’m not dirty on the bureaucratisation of DDT and pathological fearfullness of mans action on the environment because I’m a creationist.

    I’m only disgusted at the DDT-holocaust-denial..

    You want to see how disgusted.

    http://graemebird.wordpress.com/2007/04/14/ddt-holocaust-denial-getting-with-the-real-world/

    There was just no need to assemble all this information, much of it probably tainted by the ecological movement, for something that we know already.

    Skeeters can evolve some resistance.

    Few people would ever have thought otherwise.

    But the history of the holocaust remains the same.

    And left-wing bureaucrats did not save lives with their anti-chemical bollocks.

    Its just the evil white dwarf talking.

    A young maiden goes dancing in the forest studying the butterflys.

    A good scene so far until that evil white dwarf shows up.

  5. With regards to that last quote, I honestly think that many of the people propagating these claims don’t really care about actually combating malaria. I’m sure some of them actually care about it and have honest intentions, but the rest mainly see this as a convenient way to discredit all enviromentalism. If this claim spreads and enters general consciousness, you can be sure it will enter every argument against environmentalist policies, despite the fact that it isn’t true.

  6. My point, such as it is, is that refuges work in limiting resistance only if in addition to not spraying in the refuges, you also reduce pesticide use everywhere else. That then reduces the overall value of the pesticide use.

    I guess the response would be “that’s right.” We have to accept that pesticides won’t solve everything.

  7. The strategies employed by one organism (skeeters) to defeat attacks by another organism (us) can be complex indeed. As I recall from Gordon Harrison’s history of antimalarial efforts, the effectiveness of blanket spraying in the 1950s was determined largely by terrain. For example, the hills and valleys of Greece did provide “refuges” for non-resistant A. Sacharovi, but where these were adjacent to heavily sprayed areas, there were partially-treated bands where the insects had received sublethal doses. Instead of preserving the genetics of susceptibility, in this case the existence of unsprayed refuges served to accelerate resistance. The devil, as ever, is in the details.
    In all, a superb post! If you will forgive me one nit-pick, please replace “loosing” with “losing” in two places.
    Again, great job!

  8. Dear Bug Girl:

    Entomologist Donald Roberts, who has worked on mosquito control for decades, has shown that DDT when sprayed on the inside of house walls repels mosquitoes, even those that are resistant. You can read an interview with him at http://www.21stcenturysciencetech.com/Presub_samples_MMH07/Fall%20Winter%202007%20articles/Donald_Roberts.pdf

    He has also written many technical articles about this, which you can easily find.

    As for IPM: it’s a nice idea, especially if you have adequate infrastructure, but do you know any place in Africa where this has worked to stem the deaths from mosquito-borne diseases?

    Having read through this and other blogs defending Rachel Carson, I think the knee-jerk reactions against DDT are irrational and immoral. Malaria is killing hundreds of people a day in a country like Uganda, and spraying houses with DDT cuts the spread of malaria–and the resulting deaths– fast. Look at South Africa, for example, and the statistics after it stopped using DDT and then returned to DDT use to curb the death rate.

    This isn’t an academic discussion, where you score points for sharp erudite answers; it’s an issue of life or death for the people involved.

  9. Excellent post. Thanks! I’ve been looking for an article like this for a while, since I’ve not got the biology background (save a few first year courses) to delve into the specialist literature.

    Now, if only I could find a way to convince those who have already made up their mind, based on ideology rather than facts and rational argument.

  10. Another great post. And I’ll second the shout out about May. She is an entomological goddess. When I first stopped by here, I wondered if Bug Girl might be her nom de blog. I hope you take that as a compliment.

  11. OMG Doug, that is the one of the nicest things anyone has ever said to me!!!
    To be mistaken for May is indeed an honor.

  12. Marjorie, I don’t think you read this very closely. What is say is that the repellancy can *either* work for or against you–depending on the species, and the LOCAL genetics of a population.

    You also must have missed the earlier post where I discussed the technical know-how and organization needed to mount a successful spraying campaign.
    It’s not at all different than what is needed to monitor resistance. BTW, several of the papers I reference were done by African scientists.

    It sounds like you are saying Africans are too stupid to use the latest science, but that would be an awfully paternalistic argument, wouldn’t it?

  13. Marjorie, your own expert (roberts) seems to be promoting IPM himself. Example: in this recent paper:
    Bull World Health Organ v.78 n.12 Genebra 2000. Spatial targeting of interventions against malaria; Richard Carter, Kamini N. Mendis, & Donald Roberts
    the approach is clearly IPM based.
    Nowhere in this post have I said DDT absolutely can’t/shouldn’t be used. I am saying we have to choose our tools cautiously, and think through the consequences. Using DDT, which has MULTIPLE modes of actions and resistance, can create a larger long term problem through cross resistance.

  14. “Using DDT, which has MULTIPLE modes of actions and resistance, can create a larger long term problem through cross resistance.”

    The main point is that the people on the ground must be free to do whatever they think they need to to destroy any source of mosquitos on the ground whensoever anyone discovers or observes a mosquito.

    I’ve been witness to Tim Lambert (DDT-bureaucratisation-holocaust-denier) poo-poohing the idea of spraying lightly inside dwellings.

    Well think if its your little baby. Little Hamisi.

    If your little Hamisi is laughing and waving his arms around you have to set up a whole series of filters stopping the mosquitoes getting from some bog 5 km away into his bedroom…

    .. Or when he gets older on the road that he walks to get to school.

    So bednets aren’t going to do it. Thats a nazi attitude which reveals clear Mallthusian pathological fears.

    Because it ensures that little Hamisi isn’t going to make it to reproductive age in a state wherein he can start a large family.

    People on the one hand will say we could get rid of the Skeeters without chemicals.

    Fine.

    Then the resistance issue can be put off until that time when thats what we need to do to protect little Hamisi.

    Spray while it still works.

    When it doesn’t work do something else.

    But you have to be able to reach for any weapon that you might be able to afford on that day without rich-white-leftist-male-taxeaters who in truth want your children dead (because of their pathological Malthusian fears) …. getting in your way.

  15. Bug Girl:
    Without even seeing your garden, I would be willing to back it against all comers, based on what I see here. Your blog. like your garden (as I imagine it) is already a valuable resource, and is on its way to becoming one of the Internets’ oases. But, to overwork an already mixed metaphor, any oasis is vulnerable to the occasional traveler who pees in the well.
    If I may suggest it, please see (if you haven’t already) Theresa Nielsen Hayden’s rules for comment moderation. You’re in control here. If anyone makes him- or herself a pest, you are totally entitled to expunge him or her. If I’m obnoxious, please delete or disemvowel me. You, and all of us, will be glad you did.

  16. jre, you are spot on–I had already decided graeme needed to be dealt with before your post :)
    And thanks for the compliment!
    Graeme, you are contributing nothing to an actual discussion. Please flog your dead horse elsewhere.

  17. Note that 21st Century Science and Technology is a LaRouche journal. Roberts displays very bad judgement in giving them an interview, and in his weaselly responses to a string of leading questions about genocide halfway through.

    More generally, there is a range of opinions in most fields. Roberts is at one extreme – he should not be quoted as authoritative.

  18. Unfortunately, while I think most entomologists would agree with me that a cautious IPM approach to useing DDT would be best, there will always be at least one entomologist that will dissagree.

    And that’s the one that will be quoted, so you have dueling entomologists.
    (cue banjo music)

  19. “Note that 21st Century Science and Technology is a LaRouche journal. ”

    This sort of casting aspersions strikes me as having some way to go as a form of argumentation.

    What we need to do is debate what happened always with a time-line in mind.

    For someone taking the opposing view to myself the central mystery would have to be why the great progress that was being made against mans most ancient microscopic enemy was suddenly reversed WHEN IT WAS.

    One would have to show that the sudden rise of a neo-Malthusian movement at that very same time was just a weird co-incidence.

  20. The best historical reference I’ve found is Gordon Harrison’s Mosquitoes, malaria, and man: A history of the hostilities since 1880. Out of print, but available from fine used booksellers everywhere. Among other things, it gives excellent perspective to the experience of public health agencies trying to defeat malaria. In the late 1940s and early 1950s, a bubbly optimism prevailed that we would be able to wipe out malaria in just a few years. The rapid emergence of insecticide resistance was a bucket of cold water on everyone’s hopes. Today, 30 of 39 known malaria vectors are resistant to DDT, including every African vector. The reason we lost ground in the fight against malaria is simple: we had already cleared malaria from every place where the biology and the behavior of the insect made vector control easy, and insecticide resistance made the crude blanket-spraying approach ineffective everywhere else. That’s not a difficult thing for most people to accept, but some find it more plausible that a dark cabal of environmentalists and population-control advocates somehow hypnotized the world’s health agencies into giving up the fight against malaria, with the objective of causing as many deaths as possible. For those folks, I can recommend an excellent tinfoil-hat haberdashery.

  21. Better job of staying on task, graeme.
    Source DOES matter. A peer reviewed journal will always be a better source material than a magazine published by an organization associated with a guy who says the Queen is a drug dealer.

    One of the key skills we teach our students in college is to evaluate the source. Who paid for the research? What does the researcher have invested? Was it peer reviewed?

    Clearly, the proDDT/antiCarson folks skipped class.

  22. “One of the key skills we teach our students in college is to evaluate the source. Who paid for the research? What does the researcher have invested? Was it peer reviewed?”
    You are teaching the children the wrong thing.
    None of the matters you say you teach above are relevant to science.
    Whats relevant is THE EVIDENCE ITSELF.
    Evidence and argument. Argument, counter-argument and counter-evidence.
    Change your curriculum and start teaching science.
    BG/moderator: I snipped a lot of repeated material and name calling out of this post>
    >>>>>>>>>>>>>>>>>
    The DDT-Malaria-bureaucratisation holocaust-deniers get a lot of mileage out of the word “BAN” and out of pretending that people who accept my timeline of what happened are blaming Rachel Carson for everything.
    But they have no positive evidence against my view of history.
    So lets see that evidence for this alternate view of history.

  23. Ok, you’re done Graeme. I am sick to death of you trivializing the Holocaust. It is a separate and tragic event.

    You also are repeating the same bogus info over and over –At Length.

    I will point out that I said *one of the things* that we teach students to evaluate is source validity–OF THE EVIDENCE. Your comment only makes sense if you want each and every person to do their own experiments.

    I let your last comment through for the amusement of others.

  24. A few hours after he posted his most recent comment here, Graeme came over to my blog and left a spittle-flecked comment demanding that I “withdraw your lying claims at bug girls blog.”
    Because I think this is an interesting and important subject, I cited the relevant sections of Harrison’s book, and linked to an insecticide-resistance database in my reply.
    But, to be candid, I have little hope for a reasonable discussion to come out of this. You have already shown more patience than I expect to.

  25. It’s because I grew up in the south. I’m almost pathologically nice…until you piss me off.

    Then the big hair comes down and the knives come out.

    The worst thing about graeme, really, is his total lack of any punctuation marks.

  26. Yes. Unsurprisingly, his response to my request for a little more substance was a barrage of five comments in a row, each of which was worse than the first. He’s banned.

    If I recall the little bit of parasitology I’ve been exposed to, the most successful parasites are those that don’t irritate their hosts too much. The very best evolve to forge a symbiotic relationship, and those provoking a strong immune reaction before reproducing are rapidly eliminated from the gene pool. This last appears to be the case with Graeme, who seems to be quickly banned from every place he posts.

    In any event, may your garden harbor more symbiotes than parasites!

  27. I don’t get it? I read the Roberts article and its a extremely good article. Its pretty much answered any outstanding questions about the controversy and there is nothing not in keeping with the facts as I understand them.

    On top of that Roberts appears to be very well qualified and clearly has experience in the field going way back to the start of when the hysteria first developed.

    I sure hope John Quiggin isn’t a scientist. We know that Larouche is a big conspiracy nut. So supposing we’ve absorbed that and are no longer shocked by it.

    Is Roberts a verified Larouche cultist? Has he complained that the magazine distorted what he was saying? Surely its the arguments of Roberts and only the arguments of Roberts that are relevant here?

    Roberts is well aware of the resistance that agricultural use of DDT will cause. But he manages to explain the mystery of why, despite this, indoor spraying is so highly effective, and I think he explains this very well.

  28. Well, there’s a lot going on in that article.
    First, the photos: they are clearly calculated to produce an emotional response.
    Second, he initially discusses his work in the AMAZON, which is quite different than Africa in both ecosystem and pest insect.
    The questions asked by the interviewer are extremely leading: “Is it brainwashing?” “The policy move was an excuse for genocide…”
    Come on!
    Lastly, he makes a case that DDT will work *in certain situations.* I’m not disputing that–I’m saying that there are many situations where it will not work.
    He also doesn’t address the issue of DDT being “appropriated” for agricultural use, which is an issue for all pesticides in use.
    He does talk about pyrethroid resistance–but there is cross resistance between DDT and pyrethroids, so if a mosquito is resistant to one, odds are it’s resistant to the other! (See above; they attack the same ion channel.)
    He and I agree that there must be an existing infrastructure for success; however, he makes this amazingly patriarchal statement: “People can’t handle their own disease problems. And you can’t empower them to do so.”

    WTF? This sounds very much like what another poster said, which I think is patronizing and insulting to developing world peoples.
    There’s a lot more oddness with Bertrand Russel and Malthusians, but it’s really not about science at all. He ends with a statement dissing large data sets, which is…mind boggling.
    In short, I think that on some points we agree; and I also think that he is showing poor judgment to be associated with a group so far out on the fringe. He is on the board of directors of several associated groups, so he isn’t just an interviewee that is misquoted.
    It’s difficult to take anything from this organization seriously.

  29. There’s a lot more oddness with Bertrand Russel and Malthusians, but it’s really not about science at all.

    Bingo! I also thought some of these comments were coming from left field — I mean, Bertrand Russell? So I looked it up. Turns out that Russell is kind of a bête noire for the LaRouche organization. One of several books they have published on the international British-enviro-Straussian conspiracy states:

    … a group of British intellectuals led by Bertrand Russell and H.G. Wells attempted to control scientific progress in order to keep the world backward and more easily managed by Imperialism. In this conspiracy theory, Wells wished Science to be controlled by some kind of priesthood and kept from the common man, while Russell wished to stifle it altogether by restricting it to a closed system of formal logic, that would prohibit the introduction of new ideas. This conspiracy also involved the promotion of the counterculture.

    I didn’t expect it, but this discussion has led into one of the darker and loonier corners of the political webosphere. Anyway, when one of your commenters refers to Bertrand Russell or Malthusians, you can make a pretty good guess as to where he/she is getting his/her reading material.

  30. You’re the first person to report this–what kind of browser are you using? I do know that if you have a very small window size, there’s a problem.

  31. One of the “junk science” articles said that the anti-ddt people “fail to understand that resistance does not imply immunity.” AYE! I think that the “Anti-DDT” crowd can understand that just fine.

    Yes, I suppose if you want to go down the road of “Well use more! more MORE MORE!” Well, then eventually you don’t have to worry about resistance, right? I mean, one would think that if you use enough, any insects will be crushed off of the sheer weight of the tons of chemicals dropped on them…..

  32. There’s a nifty graph that Metcalf did that shows a dose-response curve over time. Alas, it looks about the same as the graph I used above with the numbers of resistant species.
    If I can find it online, I’ll stick it in.

    Here’s one example–not dose response, but clearly showing diminishing returns on spraying:

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