The web is buzzing about a new pyrethroid-resistance study of New York City bed bugs by researchers at the University of Massachusetts and Seoul National University. Pyrethroid-resistance is just one reason it is often so hard to get rid of bed bugs.

Two of the many articles picking up on the study’s results included this item in the U.S. News and World Report Health Blog today, and this article from Monday’s LiveScience.

As the U.S. News Health blogger reported,

Bed bugs in New York City, where infestations have grown in recent years, appear to have developed nerve cell mutations that weaken the effect of the pyrethroid toxins, such as deltamethrin, commonly used against them, according to a report in the current issue of the Journal of Medical Entomology. Such nervous system poisons normally would paralyze and kill the nocturnal blood suckers.

Toxicologists at the University of Massachusetts Amherst and Korea’s Seoul National University found that the New York City bed bugs are now as much as 264 times more resistant to deltamethrin than an easier-to-kill type of bed bug found in Florida.

Pyrethroid-resistance is no surprise to us, since it has been found elsewhere.

Unfortunately, the current round of press coverage of the U Mass-Amherst / Seoul National U study may give those not in the know about pyrethroid-resistance the sense that this is a “New York City” problem, which it isn’t.

This 2007 article in PCT Online from Alvero Romero, Michael Potter and Kenneth F. Haynes outlines a study comparing pyrethroid-resistance found in populations from around the US:

Further testing of third-to-fifth instar nymphs from 16 different field populations indicated that pyrethroid resistance in bed bugs, while not universal, may be widespread (see accompanying map and table on pages 44 and 48). Using a “discriminating” dose equivalent to 10 times the labeled rate of deltamethrin (0.6 percent), 14 of 16 populations collected in Kentucky, Ohio, Michigan, New York, Massachusetts, Virginia, Florida and California were resistant (0 percent mortality), one field population from New Jersey was deemed “intermediate” (45 percent mortality), and one of the two populations collected from the same building in California was relatively susceptible (100 percent mortality).

(Information on getting a copy of this study follows at the bottom of the post.)

The Livescience article helps put the new pyrethroid-resistance data in perspective, with the help of Dr. Lou Sorkin, a friend to Bedbuggers everywhere:

Unless the researchers sampled every population of bed bugs in New York, it is unlikely that all NYC bed bugs are resistant to the insecticide, said Louis Sorkin, an entomologist at the American Museum of Natural History in New York.

Also, most pest control companies rely on more than one insecticide to combat bed bugs, he said. The ideal is to use a combination of chemicals that have different modes of action — perhaps one is good at killing the adults and nymphal stages immediately while another is better at lingering and killing bugs days later — and come from different chemical families, not just pyrethroids, Sorkin said.

Exterminators also have different ways to administer insecticides, which can make a difference — foams, powders, aerosols. However, over-the-counter aerosol bombs are not recommended. They just cause the bugs to scatter, Sorkin said, and fail to get inside cracks where bugs can hide.

“Some people don’t like to say they have bed bugs. They try to take care of it themselves,” Sorkin said. But amateur attempts often just push the bugs away for a while and spread them into neighboring properties.

Lou reminds us not to take an infestation lightly. If you’re using traditional treatments for bed bugs, a multi-pronged approach is best. The article notes that Integrated Pest Management (IPM) solutions go beyond sprays and dusts:

Techniques include caulking, spackling and using other sealants to fill cracks and crevices, refinishing and sealing floors, injecting frozen carbon dioxide “snow” into electronics to freeze pests, re-painting walls and other surfaces, using low-moisture steam and clothes dryer heat to kill bugs, and injecting bug-killing dust into electrical outlets and switches.

Commodity fumigation (usually done by sulfuryl fluoride gas, including Vikane TM) is also mentioned by Lou in the article. (The home itself obviously must be treated thoroughly if items are to be gassed and returned to it.)

Thermal heat is not specifically mentioned, but is now an option which can be effective.

If done properly, no bed bug is resistant to sulfuryl fluoride (Vikane TM) or thermal heat. However, these options can be more expensive, and are not available everywhere.

Pyrethroid-resistance is a good reason for the pest control industry to keep seeking alternative solutions to bed bugs and for all pest professionals, landlords, tenants, and property owners to get serious about an aggrerssive, multi-pronged approach to fighting bed bugs.

The new research study referred to in these articles is:

Yoon, K. S., Kown, D. H., Strycharz, J. P., Hollingsworth, C. S., Lee, S. H., and Clark, J. M. 2008. Biochemical and Molecular Analysis of Deltamethrin Resistance in the Common Bed Bug (Hemiptera: Cimicidae). J. Med. Entomol. 45(6): 1092-1101.

(Use accession number 185379 to get a PDF of this item from the Armed Forces Pest Management Board Literature Retrieval System! Accession numbers for items below are also noted where available.)

Also see the study referenced in the PCT Online article above:

Romero, A., M.F. Potter, D.A. Potter and K.F. Haynes. 2007. Insecticide resistance in the bed bug: a factor in the pest’s sudden resurgence? J. Med. Entomol. 44 (2):175-178. Accession number 183531.

The PCT Online article linked to above also suggests the following articles:

Myamba, J, C.A. Maxwell, A. Asidi and C.F. Curtis. 2002. Pyrethroid resistance in tropical bed bugs, Cimex hemipterus, associated with use of treated bednets. Med. and Vet. Entomol. 16, 448-451. Accession number 175921.

Boase, C.J., G. Small, and R. Naylor. 2006. Interim report on insecticide susceptibility status of UK bedbugs. Professional Pest Controller. Summer 2006:6-7.

Karunaratne, S.H.P.P., B.T. Damayanthi, M.H.J. Fareena, V. Imbuldeniya, and J. Hemingway. 2007. Insecticide resistance in the tropical bed bug Cimex hemipterus. Pestic. Bochem. Physiol. 88, 102-107. Abstract.

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I was poking around some historical items, for reasons which will soon become revealed to you, dear readers, when I found an interesting document from the Commission for Environmental Cooperation which outlines the history of DDT in Canada, the US (the three countries represented on the CEC) until 1997.  Click here to load a PDF of History of DDT in North America to 1997, from the CEC.

Please understand: we don’t think DDT is a solution for bed bugs now. Sure — despite being ecologically-minded and kind of nervous around pesticides in general — like many of you, my first reaction to bed bugs was “Bring back DDT!”  However, learning more made me realize this was not practical, and not even an effective solution anymore. I don’t want to entertain a discussion of this.

The fact is, bed bugs started showing resistance to DDT as early as 1948 in Hawaii, and reports from the 1950s and 1960s, as well more recently, tell us that bed bugs were not killed when spraying with DDT was done for malarial mosquitos. (This BBC article from 2001 claims that DDT spraying for malarial mosquitos in South Africa made bed bugs more active. Shudder.)

If you don’t believe bed bugs are resistant to DDT, Renee has previously laid out all the evidence for you at New York vs. Bed Bugs, in this post, and I encourage you to check it out.

However, I do think this CEC history of DDT is relevant to us today, in terms of thinking about the laws around pesticides.

In 1969, the US Department of Agriculture (USDA) cancelled the registration of certain uses of DDT (on shade trees, on tobacco, in the home, and in aquatic environments) after studying the persistence of DDT residues in the environment. Applications on crops, commercial plants, wood products, and for building purposes were cancelled by the USDA in 1970. Under the authority of the EPA, the registrations of the remaining DDT products and DDT-metabolites were cancelled on 4 January 1973, with the following exemptions: public health use for control of vector-borne diseases, USDA or military use for health quarantine, and use in prescription drugs for controlling body lice. All of these remaining uses were voluntarily cancelled (due to failure to pay maintenance fees) by October 1989.

Emphasis mine.

I had not realized that even after being outlawed in the US for home and agricultural use in 1970, and after being prohibited for most other uses in 1973, you could still legally get DDT until 1989 for some purposes including treating pests which caused vector-borne diseases (a category which does not include bed bugs) and for body lice.

This is relevant because, while DDT does not appear to be one of them, there are classes of chemicals which are currently outlawed in certain areas which are effective against bed bugs.  It is worth remembering that agencies can make exceptions to allow some of those substances to be labeled for bed bug use and allowed in controlled situations.  Winston gives us a glimpse of one product not available for this use in the US, Ficam, here:

… as mentioned in my first piece, misguided legislation have forced many products out of the market. Some due to legitimate concerns, some due to a lack of true scientific evaluation and feel-good politics, and some because they simply could not afford to maintain registration due to increased requirements. A prime example of this is Ficam, a material which is used elsewhere with a degree of success, but here in the US is no more. The same in fact would have been true of Drione, one of the remaining effective dusts. Prior to the bed bug outbreak this product was due to go by the wayside simply because of economics, and now it is probably one of the good long-term materials when used properly in wall voids, outlet covers and cracks and crevices.

As Winston has reminded us elsewhere, even pyrethrins are outlawed for use in city-owned buildings by Local Law 37.  Despite pyrethroid-resistance, pyrethrins can be an important part of a bed bug treatment plan.  This law is misguided and means residents of public housing, homes, kids in public school classrooms and people in city-run institutions may have less effective bed bug treatment.

And while some might think LL 37 is protecting New York citizens’ health, you have to ask yourself: if the pesticides prohibited in publicly-owned buildings, then they’d be outlawed in private schools and apartment  buildings too, not just in the city-owned buildings.

In New York, it’s one reason we need to encourage the city to take action.  Some legislative changes can help in the fight against bed bugs.

As Michael Potter said last summer at the PCT Bed Bug Seminar,

“If there is a classic example of why you don’t eliminate entire classes of pesticides,” Potter said, “bed bugs are it. We’re in a heap of trouble in terms of the products we have available to fight this pest,” citing several classes of chemistry that are no longer available (e.g., organophosphates, carbamates, etc.) and the growing threat of pyrethroid resistance. As a result, he said, “I don’t see how this problem is going to get better. I think it’s going to get chaotic. This is the most challenging pest I’ve encountered in my career. We’re in big trouble.”

We are in big trouble.

I don’t even know how to begin to help lobby for better pesticides.  I assume pest control operators, entomologists, and their professional organizations are doing so.  Maybe they can tell us if there’s something we bed bug activists can do to help.   It seems so essential that we get all the help we can get in fighting bed bugs.

Finally, because someone always asks: I am not pesticide-happy. I am, in fact, more enthusiastic about non-chemical solutions to bed bugs. Not only because they do develop resistance to pesticides, but also because I seek safe, ecologically-friendly, easy solutions to bed bug problems.

Steaming, thermal treatments, and other solutions are labor-intensive. Steam requires dedicated, persistent, repetead work (and in most cases, probably requires the backup use of targeted use of dusts or sprays).

Thermal treatments require an experienced operator and expensive equipment. For those who can afford it, and who have access to knowledgeable providers, this can be a good option. We can only hope that effective non-chemical options will become more widely available and less costly.

When we’re talking about the extensive spread of bed bugs, though, we have to be realistic about the types of treatment likely to be implemented. Making sure the most effective pesticides (or at least, a variety of pesticides, to help offset resistance to individual chemicals) is probably better for both people living with bed bugs, as well as the environment.  Because getting rid of the problem more quickly means less pesticides will be needed.

Once the bed bug epidemic is under control, and we’re back where we were in the 1970s, with isolated outbreaks, then we might be able to deal with the problem in other ways. We’re a long way from that situation.  And we will probably never get there again if pest control operators are not able to use whatever tools they can safely use in order to eliminate them.Similar Posts:

None Found

This is a FAQ on diatomceous earth (DE).

Wikipedia tells us:

Diatomaceous earth, also known as DE, diatomite, diahydro, kieselguhr, kieselgur and Celite) is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder, and is very light, due to its high porosity. The typical chemical composition of diatomaceous earth is 86% silica, 5% sodium, 3% magnesium and 2% iron.

Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, as a mild abrasive, as a mechanical insecticide, as an absorbent for liquids, as cat litter, as an activator in blood clotting studies, and as a component of dynamite. As it is also heat-resistant, it can be used as a thermal insulator.

Freshwater DE is used by many in fighting or preventing bed bugs. It is not a pesticide, but a dust made from granulated fossil shells; it kills bed bugs when they make contact with it. So a thin dusting in places where it won’t be disturbed can be helpful in killing bed bugs.

I would caution people against trying to deal with a serious infestation using just DE (or vacuuming, or contact killers such as enzyme cleaners, 90% rubbing alcohol, steam or boiling water). You may have a serious infestation even if you have not been seeing bed bugs, and a PCO experienced with bed bugs should be brought in, or other treatments such as professional Vikane gas treatment (for entire buildings) or professional thermal treatments.

We’re also told DE can take ten days to kill bed bugs once they come into contact with it.

That said, people may be able to benefit from augmenting treatment with DE, and others may use it as a preventative against new infestations.

I have cobbled together advice from several readers who posted to a “Tales of Woe” thread, where diatomaceous earth was the subject.

There are pesticide dusts, but the comments below refer only to food-grade freshwater diatomaceous earth (since those which are not food-grade and from freshwater sources are less safe). If you use DE, you need a good tool for applying it. You can buy a puffer. Some have mentioned using a paintbrush or a turkey baster, but I would recommend getting the best tool you can for applying a thin layer of dust. More is not better in the case of DE: bed bugs won’t walk through a thicker coating and so it won’t have a chance to kill them.

Also, since I recommend you work with a PCO, I suggest that you do not apply DE during the course of their treatment without consulting them. They may be using other substances that this may not work with (always a danger when you use anything of your own volition during treatment!) So ask. Also, if you are vacuuming often (as is frequently necessary during treatment–again, ask your PCO) you’ll want to reapply a thin coating when the DE is vacuumed up. It may wear out your vacuum more quickly, so be warned.

Since you should not be inhaling DE, you don’t want it somewhere it will be disturbed. Similarly, putting it on soft furnishings like mattresses and sofas seems like a dangerous idea. Did you ever sit on a dusty sofa? You do not want DE in your lungs, not even freshwater DE.

I would also say that although fresh water / food grade DE is safe if used properly, you should probably use a good respirator mask when applying any dust (such as the one recommended below), and disposable waterproof gloves when applying this or any other substance. No dust is safe if inhaled. Do not use large quantities that are likely to be kicked up and inhaled, and do not place in windowsills where a breeze might blow the dust around.

In our forums, Jim (spideyjg) contributed the following important safety warning (note: I am copying spideyjg’s entire statement below, so you do not need to leave this FAQ):

DE or any pesticide dust is for use only in areas where the living things present are ones you want to die. Cracks, crevices, wall voids etc, applied then left undisturbed.

Apply it, wearing your PPE, Personal Protective Equipment, ventilate the place when done before removing your safety gear.

See the CDC’s Occupational Health Guideline for Amorphous Silica (PDF here), or NIOSH Pocket Guide to Chemical Hazards on Amorphous Silica.

DE is an inhalation hazard per the CDC. It can cause silicosis. It can be quite safe when used properly but isn’t as safe as some hucksters make it out to be.

Your choice to either listen to the CDC and NIOSH who are charged with health and worker safety or some schmoe selling DE as a miracle BB treatment.

Don’t get me wrong I used DE and swear by it as an effective BB weapon but have done enough homework to realize it isn’t as benign as some portray it.

You need to protect yourself from inhaling it and NIOSH recommends a filter depending on the concentration but go for a P100 filtered respirator.

KillerQueen suggested this,

“I would use a Comfo Classic Respirator no matter what the label tells you.

I use GME-P100 cartridge part number or reference number 815182.”

Whatever respirator you get ensure it is P, N, or R100 rated for finest particulate filtration if you are using ANY pesticide dusts.

Your one set of lungs, your choice, but decide on the facts.

Good advice, thanks Jim!

This is the MSA Comfo Classic respirator Jim quotes KillerQueen in recommending (on Amazon): Respirator,Half Mask MSA 808071

This is the GME-P100 #815182 cartridge (on Amazon): Msa 815182 Gme/P100 Shortstack Combination Cartridge

The quotations from others below are, unless otherwise noted, from this thread of comments. (Since a lot else in those comments is not relevant, I won’t just send you there.)

RemedyJones asked,

I am reading mixed messages as to the safety of using DE. It had been recommended that I use fresh water DE since I have pets. Apparently it is food grade. I’ve seen comments on the web stating that it shouldn’t be breathed in or used around areas of high traffic. Others state that it is safe to sprinkle on carpet and floors that it won’t harm pets or humans. So what’s the deal?

Geoffrey Day said:

First off, I am an adviser to a business that sells DE along with other natural and organic pest control products so I am naturally biased. I also use DE and since I haven’t had any BB problems personally, I cannot speak first hand on that matter.

Dirtworks started selling organic fertilizers and learned from farmers that this DE stuff was really something. It is routinely used to quell mite outbreaks in chickens. Lots of farmers swear by this stuff.

I am not a PCO nor an entomologist and perhaps we should have them weigh in here to get their official words on DE.

Fresh water / food grade DE is an ingredient in most pest control powders including numerous best selling flea powders.

At the Dirtworks shop John has a dog named Angel. Angel is routinely treated with DE when necessary, both internally and externally. Angel is doing great! We should all have such an Angel.

If you are concerned about breathing the dust, then avoid breathing it by using the best dust mask you can find. [editor's note: Bedbugger strongly suggests you use a respirator mask, not a dust mask, to apply DE. Please see spideyjg's comments above.]

… What you want to do with DE is apply a light film. What I mean by that is a VERY LIGHT film.

If you are applying it in a way that you are kicking up visible dust, you are putting WAY too much down.

Wally Tharp (the inventor of the DE manufacturing process) routinely would illustrate the safety of this product by mixing a tablespoon of it in a glass of water and then drinking the water. Wally today is in his 80’s and going strong.   (Editor’s note added 3/2008:  In response to a reader’s question below, I want to make it absolutely clear that Bedbugger does NOT recommend that you experiment with this.)

Reader Bugalina recommends the use of a small hand bellows to apply DE. (We can edit this when she tells us where she got it.)

Perma-guard, who make food grade freshwater DE, discuss applications of DE in various household settings. They do not list bed bugs, but we are told this product works on bed bugs. (Remember, bed bugs have only become a big problem very recently, and everyone has to catch up with that.)

John Meshna, the owner of Dirtworks, a company that sells (among other things) fresh water DE (fossil shell flour) and also a D-20 which is DE plus pyrethroid insecticides, says

Diatomaceous Earth … is a dust and if you have a low tolorance for dust, you can wear a dust mask or get some one else to apply it. [editor's note: Bedbugger strongly suggests you use a respirator mask, not a dust mask, to apply DE. Please see spideyjg's comments above.]I’ve used both the D-20 with pyrethrin and the fossil shell four and it works great to kill fleas, ticks, silver fish and all soft bodied bugs. fortunately i’ve never had to suffer the ravages of bed bugs but, if I did, I would not hesitate to use it everywhere in my house. Why not? I’ve done it already for other pests.

Professional pest control companies make lots of money selling their toxic products and they don’t like products like DE that anyone can apply and work forever, so long as they are down. Even they will tell you that no matter what they do, the bugs might return. DE last forever. It’s a mineral and doesn’t gas off or biodegrade over time.

It does have to come in physical contact with the bugs, so, if there any advantage to the synthetic chemicals is that they can kill by inhalation alone, but this is also what makes them so toxic to us and other warm blooded animals.

I could say more but, check out the Perma-guard web site and mine at dirtworks.net if you need more information.

Nobugsonme said:

John, I believe food grade DE is safe if used properly, though sometimes we hear from people who are clearly over-using it or putting it places they will be breathing. Everyone reading this should realize that you must educate yourself if you apply any products–whether it’s food grade DE or a pesticide.

No matter what you use, I also caution anyone against trying to fight an infestation of bed bugs with just food grade DE (or any other product in isolation, for that matter). Please see a qualified PCO–one with bed bug experience.

The other side of that is that you need to make sure your PCO knows what you’re using (whether it’s Kleen Free or DE or something stronger). Some applications you might do could work against something they might do, and you would have no idea unless you discuss it with them.

PCO Sean referred us to his brief post on DE at the Bed Bug Resource which reminds us that we should call a PCO who is experienced with bed bugs right away (though I’m not a PCO, I tend to agree). Sean warns against the dangers of DE if incorrectly applied, though I think this is even more a problem with non-food grade, non-freshwater DE.

It is worth noting that some PCOs will NOT treat you if you have self-treated. They may refuse to do the work if you have put DE or other substances down before they come in.

As always, Your Mileage May Vary. If you want to use any technique or tool in your bed bug war, research it, find knowledgeable and preferably unbiased advice, and make sure you are cautious. More than anything else, remember how hardy and resilient bed bugs can be. Don’t try one tactic, try every one you can, provided they work together. And I seriously think a PCO can help you figure that out, as talking to others here can.

But don’t do something because someone told you it would work or “be enough.” I think it might figure in many treatment plans, but especially be useful to people who don’t yet have bites or any signs of bed bugs (but know they were exposed to them), or those who’ve gotten rid of bed bugs (and would like some insurance). For those with active infestations, the DE with pyrethroids might be the most useful, alongside other treatments. Remember, ask your PCO.

Application

I have not used one, but some readers have used a bellows duster like this one, to apply DE or other dusts. There is doubtless a trick to using it, and it might take practice, but a tool such as this might be useful to those who wish to use DE. (Other methods suggested include using a blusher brush — obviously, one used strictly for this purpose — to apply it, or using the kind of plastic container that dispenses mustard to squirt or dab it. In any case, apply DE lightly and as deeply as possible to cracks and places it won’t be disturbed or kicked up, touched or breathed, by you or anyone else.

Share your DE stories and ask questions about DE, in the comments below.

Buy Diatomaceous Earth 2.5 pounds (DE) at Amazon.com:

Full Disclosure: Bedbugger has an affiliate advertising relationship with Amazon. If you purchase via the links to Amazon.com above, a small percentage of your purchase goes to support Bedbugger, at no additional cost to you.

Update (5/2009):

A new post on New York vs. Bed Bugs today examines the following study:

Journal of Medical Entomology 46(3):572-579. 2009
doi: 10.1603/033.046.0323
Addition of Alarm Pheromone Components Improves the Effectiveness of Desiccant Dusts Against Cimex lectularius

Joshua B. Benoit, Seth A. Phillips, Travis J. Croxall, Brady S. Christensen, Jay A. Yoder, and David L. Denlinger.

This article notes that

The efficacy of diatomaceous earth seems to depend somewhat on the formulation; sometimes it works and sometimes it does not (Allan and Patrican 1994). Resistance also seems to be an issue with diatomaceous earth (Korunic and Ormesher 2000, Rigaux et al. 2001). Previous studies concluded that Dri-die seems to be superior to diatomaceous earths (Allan and Patrican 1994, Appel et al. 1999), and that is what we observed in this study during short-term exposure. Two key points that may alter the effectiveness of Dri-die and DE are the duration of bed bug exposure and the residual effects. Indeed, future studies are needed to test these two aspects for C. lectularius.

Like Renee,

The only thing I did know was, sometimes it works, sometimes it does not, clearly, but I thought the problem was with application and the difficulty of ensuring exposure, not resistance. Resistance never crossed my mind. In fact, I’m pretty sure I’ve heard “bed bugs cannot develop resistance to DE” more than once.

It is important to take note of this, and consider that it may account for why DE does not always work for people (even if they apply it properly, even if bed bugs walk over it, even if they allow sufficient time).

I am re-opening comments on this FAQ, due to this additional information.
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