Diatomaceous earth (DE), a dust, can be used to kill bed bugs.
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 diatomaceous earth 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 we 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.
Although fresh water / food grade DE is safe if used properly, experts recommend using 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.
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):
If these products are no longer available, you may find respirators and P100 filters by searching on Amazon:
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.)
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.
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.
Readers have used a bellows duster like the Pest Pistol Mini Duster to apply DE.
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.
Recent research on DE efficacy
First, a 2009 article “Bed bugs: are dusts the magic bullet?” in Pest Management Professional magazine by Michael Potter explores the effectiveness of various dusts, including Mother D (which is 100% DE). You can read it here.
We tested five different dusts representing two insecticide categories: two pyrethroid-based dusts, DeltaDust (deltamethrin 0.05 percent) and Tempo 1% Dust (cyfluthrin 1 percent); and three desiccant dusts, Drione (pyrethrins 1 percent, piperonyl butoxide 10 percent, amorphous silica gel 40 percent), Mother Earth D (diatomaceous earth 100 percent), and NIC 325 (limestone 99.5 percent). The efficacy of each product was evaluated by confining adult bed bugs (three replicates of 20 insects) from the respective populations on black filter paper circles treated at label rates, (or about 200 mg of dust per cm2). Exposure of bed bugs to the dusts was continuous, and mortality was recorded daily.
The research found that Mother Earth D brand DE “caused substantial (>90 percent) mortality of susceptible and resistant bed bugs within four days and all bed bugs were dead after 10 days.” (Some of the dusts Mother Earth D was compared with in this study have added pesticides, and some of these worked faster, but none worked better over the ten day period.) You can read the results and analysis here.
Remember, though, the dusts were tested in laboratory conditions. You cannot force bed bugs to walk on dusts as the lab researchers can. Until they walk across it, they will not be killed by a dust. So knowing that a product can kill bed bugs in 24 hours does not mean it will kill your bed bugs within any specified period of time.
Also, a new post on New York vs. Bed Bugs examines the following study:
Journal of Medical Entomology 46(3):572-579. 2009
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.
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).
Last updated 16 July 2012