Don’t throw your DEET Away!

deetfailThere’s been a lot of reporting about new research about the insect repellent DEET this week. Unfortunately, some of the media didn’t quite get it right.  Headlines like this one were common…and completely wrong.

The media coverage left a lot of people confused about DEET, and if it still worked. The results of the research were a lot more nuanced than “DEET suddenly stopped working so we are all screwed.”

Here is what the average person being bitten by mosquitoes needs to know, condensed:
DEET still works fine. It’s still one of the best insect repellents out there.  We know a way it might become less effective now, as demonstrated in the laboratory.

The un-condensed version:

DEET is one of our oldest and best insect repellents.  It’s universally acknowledged as the best repellent around, and has broad activity against several types of biting flies and ticks. This is why a problem with DEET is big news–it’s invaluable in preventing transmission of several different diseases.

Amazingly, scientists are just beginning to understand how DEET works, even though it’s been in widespread use for 50 years.  We know it stops ticks and mosquitoes from biting, but the exact mechanism of how that happens is still not clear.  Does it make us ‘invisible‘ by blocking mosquitoes from smelling? Does it smell horrible to biters? It’s still not settled science yet.

Martha Stuart says that's not a good thing

That’s important to know, since if we know how something works, we can copy it and try to make new and better controls.  There is always a concern with evolution of resistance in insects–they are commonly used to study genetics and mutations for a reason.   Insects breed fast, and they breed often–which means that small genetic changes, if they are helpful at keeping a bug alive and having sex, can spread quickly through a population.

Resistance to DEET, our most powerful and broad spectrum insect repellent, would be a very bad thing.  And so it makes sense that entomologists interested in human health would be studying how DEET works.

Evidence of genetic resistance to DEET in mosquitoes has actually been around since 1994.  In 2010, researchers found that they could increase the frequency of a gene that made mosquitoes ignore DEET to 50% in a couple of generations. That’s alarming, but that was in a laboratory-bred colony.

‘Laboratory-Bred’ is an important distinction for both that study and the recent one.  Mosquitoes in a cage have only one source of food (often the hapless graduate student that is rearing them).  They can’t fly off and look for other people or animals to bite.   It also means that their sexual choices are limited to other mozzies in the cage, so resistance can evolve more quickly that it would out in the wild where they have a wider choice of hookups.

Scientists use work in the lab to model the real world.  It helps us understand how organisms grow, change, and respond to their environment.  That  doesn’t mean that it’s a firm prediction of what will happen out in the larger world, especially with a group as diverse and wily as mosquitoes. That’s why I think headlines like the one at the top are irresponsible, and mangling the message of the research.

You can see an interview with one of the researchers here;  note she is careful to repeat that we should not discard DEET wholesale on the results of this research!

“What this work indicates is that there may potentially at some point in the future be some problems  with the repellents that we have, that we need to be aware of in advance.   Possibly we can use this information to  alter the repellent DEET to make it more effective, it may also help us in finding new repellents because we will know if [mosquitoes] are able to overcome certain things……Even though repellents are working fantastically at the moment, what this tells us is maybe how to prevent problems cropping up, and how to alter things for the future to make them more effective.” [emphasis mine]

Additional Resources:

Articles referenced in this post: 

  • Stanczyk N.M., Brookfield J.F.Y., Field L.M., Logan J.G. & Vontas J. (2013). Aedes aegypti Mosquitoes Exhibit Decreased Repellency by DEET following Previous Exposure, PLoS ONE, 8 (2) e54438. DOI:
  • Ditzen M., Pellegrino M. & Vosshall L.B. (2008). Insect Odorant Receptors Are Molecular Targets of the Insect Repellent DEET, Science, 319 (5871) 1838-1842. DOI:
  • Jaramillo Ramirez G.I., Logan J.G., Loza-Reyes E., Stashenko E., Moores G.D. & Vontas J. (2012). Repellents Inhibit P450 Enzymes in Stegomyia (Aedes) aegypti, PLoS ONE, 7 (11) e48698. DOI:
  • Rutledge L.C., Gupta R.K., Piper G.N. & Lowe C.A. Studies on the inheritance of repellent tolerances in Aedes aegypti., Journal of the American Mosquito Control Association, PMID:
  • Stanczyk N.M., Brookfield J.F.Y., Ignell R., Logan J.G. & Field L.M. (2010). Behavioral insensitivity to DEET in Aedes aegypti is a genetically determined trait residing in changes in sensillum function, Proceedings of the National Academy of Sciences, 107 (19) 8575-8580. DOI:


Entomology and Critical Thinking

One question I’m often asked is why this Bug Blog is also listed as a skeptical blog.  The connection between skepticism and bugology isn’t always immediately apparent, I guess, but it seems quite logical to me.

There are many, many bogus devices that claim to repel insects, and I think it’s important to name names. There are far too few convictions for fraud in the insect repellent business.  I’ve called out some of these in the past; the iPhone app that supposedly repels mosquitoes, for example, or the Bug Banisher that releases an imaginary “negative ion field.” It seems sometimes like as fast as I can name and shame, there are new and even more silly devices on the market.

Case in Point: shoo!TAG™ insect repelling credit cards


From their website:

Shoo!tags “utilize an understanding of nature’s energetic principles in combination with physics and quantum physics, as well as advanced computer software”.  What exactly does that mean?  Well, just as the magnetic strip on a credit card is encoded with specific information, there is a three dimensional electromagnetic field embedded in the Shoo!tag.  Shoo!tag uses the energy field that a animal emits, then adds other frequencies that repel insects.  Although they don’t actually kill insect pests, these frequency barriers disturb and confuse the pests.  Essentially, the pests don’t want to be anywhere near the Shoo!tag wearer.  

By now, your BS antennae should be quivering. Frankly, anytime someone uses the word “Quantum”, you should be suspicious. Or when something with no power source claims to generate an electromagnetic field. Reading the disclaimers about why the tags might not work as promised can be rather hilarious:

“Possible reasons shoo!TAG™ may not be working: The tag is near or has been near a strong frequency (cell phone towers, electric transformers, fault lines, electronic home security systems, etc.) which interferes with the coding in the magnetic strip.”

Ah! That’s why it didn’t work–I live in the US where those things are rather difficult to avoid.  According to recent pressshoo!TAG™ is a >$600,000 dollar business. That’s probably because each arthropod needs its own tag. You can’t just buy one; you need a chip for:

  • Mosquitoes ($19.95)
  • No-see-ums ($19.95)
  • Chiggers ($19.95)
  • Ticks ($19.95)
  • Flies (species not specified, but presumably not mosquitoes or no-see-ums, which are, in fact, flies) $19.95

For full “protection” in the woods, that’s about $100, although they do have a Mosquito-Chigger-Tick pack for just $39.95.  Each tag lasts about 4 months, unless you have an especially vigorous energy field.  Oh, and you have to outfit your pets too–the tags above are (literally) dog tags.

That’s a lot of money, and it’s also a lot of risk.  You can DIE from diseases transmitted by ticks and mosquitoes. It’s really not something that lends itself to self-experimentation.

I was all ready to go postal about this when I realized that someone had already done that work for me.  Major props go to Anaglyph for masterful work in exposing just how shabby Shoo!TAG’s claims for their products are.  He’s been writing about this since 2009; you can find an archive of all his Shoo!TAG posts here.  His series of posts is an excellent example of how one person with a blog can make a difference. 

He’s done a great job explaining why the these devices can’t possibly work without massive violations of physics as we know it. Since their claims of magical electromagnetic field creation are bogus, I don’t think I need to bother explaining why the energy field these tags don’t generate….. would not repel insects anyway.

I liked Anaglyph’s recent letter to Shoo!Fly’s CEO so much I’ll reproduce a large part of it here:

My concerns with ShooTag are many: firstly, you are taking advantage of people by selling them something which, although it is not supported by any known science, you continually attempt to frame in a scientific context. In other words, you use ‘sciencey’ sounding terms to attempt to make ShooTag sound credible.

For a start, you offer up ideas such as the ‘trivector’ mechanism, ‘energy’ fields and the vague concept of biological ‘frequencies’ as if they are proper scientifically supported notions, which they are not. At best these things are speculative, but mostly they are just plain nonsense. In addition to presenting pseudoscience as science, you imply that the mechanism of ShooTag is somehow supported by actual scientific concepts of which you plainly have little comprehension, such as quantum physics, fractal mathematics and Schumann Waves.

All these things are meaningless in relation to your product, at least in any way that have attempted to demonstrate so far. You also use the names of scientists like Albert Einstein and Geoffrey West, whose work you clearly don’t understand, in a manner that suggests that their theories offer support of your own speculations (which they most certainly don’t). This is misleading and irresponsible.

In addition to all this, you regularly refer to scientific ‘experiments’ which you say demonstrate not only that your product works, but that it works extraordinarily well. The experiments you reference either show nothing of the sort (such as your ‘Texas A&M Field Trials’ which were scientifically ridiculous), or don’t have substantiation of any kind (like the supposed ‘European Trials’ which you have mentioned on several occasions on the web but from which you have never provided any data whatsoever, or the supposed supporting video from ‘the Japanese Ministry of Health’ which you boasted about on your site but which never materialised there for anyone to see). You also continue to heavily infer that credible organizations are involved with your product (Texas A&M University, Texas State University, the Japanese Ministry of Health, the Finnish Olympic Team) when it is clear that no such endorsements have been made or were intended (as is quite evident from my conversations with the administration at Texas State University, and their requirement that you remove any such TSU endorsements from your site). Excuse me for saying so, but responsible companies with legitimate products do not undertake this kind of deceptive behaviour.

In short, you want everyone, particularly your prospective customers, to think that ShooTag is validated by science and approved by authoritative institutions, yet you have nothing to support your claims other than self-generated hyperbole and subjective customer testimonials. No science.

Oh, SNAP.  That. Was. Awesome.
And there’s more–read the full letter for a masterful spanking of a woo peddler.

Why am I telling you about this in a rather longish post? I discovered that Shoo!TAG donated $30,000 worth of their “units” to a children’s bible camp in Zambia in April 2011.  And they sent tags to Haiti after the earthquake (through a bible missionary chiropractic group. Talk about insult to injury!).  Shoo!TAG issued press releases about all this, and I strongly suspect they also took a nice tax write-off on their used (not even new!) plastic bits as well.

What they are doing is just….vile.  I can’t think of a more descriptive word.  Sure, these tags seem like innocuous pieces of crap that will part gullible people from their money.  It’s all fun and games until someone dies of malaria, yellow fever, or lyme disease, because they thought hanging a credit card around their neck would protect them.

The problem is, to whom do you report people selling this kind of woo to?  There has to be a way to make an obviously fake device like this go away.


The Federal Trade Commission has prosecuted people selling deceptive devices before, but they sure don’t make reporting easy. Their Complaint Assistant is mostly focused on online fraud and identity theft.   The Consumer Product Safety Commission is a possibility, but again, shoo!TAG™doesn’t really fit into any of their categories.

When you look at the FDA Guide to reporting problems, the categories for human health problems don’t quite fit.  It’s easier to report shoo!TAGs for veterinary use than for people.  Since heartworms,tick paralysis, and equine encephalitis are just some of what users of these tags put their pets at risk of catching, that’s not entirely a bad thing.

A quick search of the EPA registered pesticides database produces no results.  These tags almost certainly fall into the category of “Minimum Risk“:

Minimum risk pesticides are a special class of pesticides that are not subject to federal registration requirements because their ingredients, both active and inert, are demonstrably safe for the intended use.

Since shoo!TAG™ is plastic and don’t do anything, I’d say they’re inert, alright. But “minimum risk”? It turns out there is some special language about that exemption:

“EPA…concluded that public health products must be supported by evidence that they are effective against the target pest.”

AH HA!  If you dig a bit farther, you can find the contact info for the EPA Ombudsman’s office, and aform to report an environmental violation.

And here is where I go all PollyAnna on your asses.
I believe that social media has the potential to truly change the way the world works.

One of the things bloggers can do with their bully pulpits—no matter how modest– is fact-check claims that businesses (or politicians!) make, and call readers to action.  While blogs and Twitter and Facebook can disrupt our lives, they also make it possible for people to draw attention to things that just aren’t right.

As blog readers, you can respond and spread that fact-checking in ways that warm the cockles of my misanthropic little heart.  Let’s harness our community power. Who knows someone at the EPA enforcement division?   Minions, mobilize!!

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