Finally, researchers on the efficacy of dusts

In the May issue of Pest Management Professional (please see the magazine digital edition here), Alvaro Romero, Michael F. Potter and Kenneth F. Haynes of the University of Kentucky describe a set of initial data on the efficacy of dusts against bed bugs. They tested two pyrethroid-resistant bed bug populations from Cincinnati and New York, one “moderately pyrethroid susceptible” population from Los Angeles, and one of those sheltered Dr. Harlan populations:

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), MotherEarth 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.

Tempo Dust killed all bed bugs within 24 hours, Drione in 72 hours and MotherEarth D (diatomaceous earth) in 10 days:

Tempo Dust killed 100 percent of the bugs from all four populations within 24 hours of exposure — a surprising outcome considering that two of the strains (NY-1 and CIN-1) were highly resistant to pyrethroids formerly administered as liquids. Drione, which includes silica gel, pyrethrins and piperonyl butoxide also produced 100 percent mortality of all populations, although 72 hours were needed to kill all bugs in the two resistant strains from New York and Cincinnati. Variable results occurred with DeltaDust depending on the resistance level of the population. While most bed bugs in the pyrethroid susceptible LA-1 and Fort Dix strains died within 24 hours, more than a week was needed to kill 100 percent of the bugs from the resistant New York strain and two weeks to kill 93 percent from the resistant Cincinnati strain. MotherEarth D (diatomaceous earth) was slower acting than Tempo or Drione, but caused substantial (>90 percent) mortality of susceptible and resistant bed bugs within four days and all bed bugs were dead after 10 days. Mortality was notably lower with limestone-based NIC 325 on all populations tested and did not exceed 50 percent even after 13 days of continuous exposure.

The authors were surprised by the efficacy of the pyrethroid dusts against both resistant and susceptible strains. They discuss possible reasons for this, the modes of action of dusts plus recommendations for PMPs on application and tools; it’s a must read in light of the continued paucity of available information. I will just quote one more thing:

In our lab studies, we have noticed that barely visible deposits still result in an accumulation of dust on the underside of a bed bug, especially toward the rear of the abdomen.

We should note that diatomaceous earth (DE) in particular is very widely used by the public to control bed bug infestations; however, people suffering from bed bugs in their desperation may use DE and other dusts inappropriately, purchase the wrong kind of diatomaceous earth (the pool filter kind), and blanket their homes with DE, which even if it is the right kind (labeled for pest control) can cause respiratory problems if applied incorrectly—the bedbugger faq on DE has safety precautions suggestions. Education is clearly needed but as always the problem of education is reach. Lately I’ve been thinking about the education problem and whenever I’m fully back we should talk about it more.

I look forward to additional findings from researchers trialing dusts and specifically additional work on the effectiveness of various DE formulations, especially with short exposures, anything to help us understand the provocative remarks in Benoit et al. that we recently discussed. I also understood that researchers at Virginia Tech had been conducting tests with dusts. (There definitely should be more instances of researchers sharing information directly with the public—and while we’re at this, making a list for Santa as it were, I really wish research journal articles were open access for the duration of our bed bug troubles. We want to know everything and we want to know it not too long after they know it, is that unreasonable?)

Alvaro Romero was very kind to answer our questions about his research earlier this year.

12 comments

  1. Dante Muccillo

    Could you tell me where I can purchase the Tempo dust that is so effective in killing bedbugs?

  2. Renee Corea

    Dante,

    In NYS this is a professional product not available to consumers.

    Because I know you are unlikely to say, okay, and leave it at that, I beg you to at the very least read both the label and the MSDS.

    You can google the name of any product to find labels and MSDS sheets, and you can google pest control products and your zip code to find stores in your area that can sell you legal materials for you to use. Please note that the Mother Earth D (diatomaceous earth) was effective, if slower, and is something you can buy as a non-professional. Whatever you do, please research and use appropriate protective equipment (a respirator and whatever else is recommended) and read and follow the labels. You want to be concerned not only about your health and safety, duh of course, but about effectiveness, so do not overapply diatomaceous earth or other dusts. Learn what a crack and crevice application means.

  3. Pingback: More tales of CIN-1: PBO and deltamethrin — New York vs Bed Bugs

  4. MaryAnn

    I am currently suffering from an infestation, and have tried to learn all I can. We have treatments scheduled to begin next week, but I have been trying to ascertain the best way to insure the highest efficacy of these treatments. This is based on what I have gleaned from my research, that direct contact methods of killing these insects is extremely difficult, and the trick is to get them to cross over the poison – sort of “lize that this post was from way back in May, but I just found it via bedbugger.com, and just read the Benoit, et al. abstract. I am a layperson, so the specifics of this paper elude me. However, as one who is battling this scourge, I am trying to leave no stone (or mattress cover…) unturned. Has anyone else duplicated the results of Benot, et al, and what has come of this research? It appears to my (VERY untrained) eye, from all that I have read (if it were paper, it would literally be reams and reams….) Again, I am unfamiliar with the process involved in getting something from the research stage to the application stage, but wonder if this methodology is available to the common PCO, and, if not, is there a way t

  5. MaryAnn

    SO sorry, I hit “submit” accidentally! Therefore, the above comment likely will appear somewhat inarticulate and disjointed. The question is, the conclusion of Benoit, et al, makes complete sense, and I would like to know how I personally can utilize this knowledge to increase the efficacy of my pending treatments. Any information is greatly appreciated. (and sorry again for the need to post twice!)

  6. Renee Corea

    MaryAnn, I’m sorry that you are going through this. I really like the research of this group of researchers; they have done tremendous work. However, in this particular instance — the addition of alarm pheromone to desiccant dusts — the insights gained do not yet equal an application. Meaning: this is not something you should try at home, I firmly believe, and the researchers themselves have said. Not yet. Not until it is studied further. One of the problems that is likely to need ironing out is the uncertainty of whether dealing with bed bugs this way — in a real-life setting where there are many unknown ways that bed bugs interact with their environment — will cause them to move and disperse to different and new harborage locations in your home — something that is generally acknowledged to be a bad thing and to complicate eradication efforts. So bottom line, something that needs further study and there are clear reasons to avoid at-home experimentation at this time. Please read the comments when we discussed this paper here. And let me know if I can be of any further help.

  7. Jane

    We suffer from a bed bug infestation, after three treatment we continue to have bites. I read about MotherEarth D and would like to know: 1. What brand is the best for treatment of bed bugs? 2. how to correctly use it? 3. is it harmful to humans at all, especially how does it effect people who suffer from asthma?
    Please help with any information. We are on the edge of a nervous breakdown over this. thank you very much.

  8. Renee Corea

    Jane, from personal experience I would say that DE is not something you want to have around when people have respiratory problems. But I am not in a position to advise you about that or about how to use it. You should read more, consider carefully and consult your doctor before you use DE in your home if you are asthmatic. It is a very fine dust.

    With some infestations you may need more than 3 treatments. (You can review the bed bug management guidelines suggested in the resources page.)

    As noted in the post above, bedbugger has a FAQ on DE with recommendations about protective gear and how lightly it must be applied (a very thin layer).

    In general I believe that a DE product specifically labeled for pest control is what should be recommended because then it has a label and instructions that you can follow. Unfortunately, there are many types of diatomaceous earth and some are not effective against pests, and/or are hazardous, like pool filter DE. By buying a product specifically labeled for killing insects, you can avoid buying something that doesn’t work, and you have specific instructions to follow.

  9. biwabi

    if you can’t afford a professional hit treatment $1,000 to $3,000 depending on the size of your place, than your best option is DE. you could even eat this thing, it’s very, very safe, just follow instructions for the application for respiratory safety. DE kills this animal, and it’s very low cost.

  10. biwabi

    just make sure you buy “DE food grade” (DIATOMACEOUS EARTH FOOD GRADE) for pets control.

  11. Paul Bello

    After reading your article above I have a question:

    The article states that 200 mg per cm2 of dust were applied for purposes of the trials conducted. Are you cetain that this was the correct quantity of dust applied during these tests? If you take a quick look at the area and the dosage, this is a lot of dust to be applied on that given area. Please advise, thanks ! paul b.

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