Diatomaceous Earth Pros and Cons

Q: Is diatomaceous earth non-toxic?

A: There is NO such thing as a non-toxic insecticide. If any chemical we used were non-toxic then it would not be able to kill any bugs either. The fact is, and the EPA demands this of us, all of the labeled products we use to manage pests in our work are pesticides, and these are defined by EPA as “any substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.” This includes growth regulators, repellents, and all “natural” pesticides that may be derived from plants or minerals, including diatomaceous earth. The most we can say is that diatomaceous earth has low toxicity to humans.

Q: Will diatomaceous earth kill fleas?

A: Yes, but there are a few things to know. While it is a natural solution for those looking to avoid chemical pesticides, it does have a downside. The bugs have to come into direct and prolonged contact with the material for it to have an effect, so you have to spread it pretty extensively throughout the home. To be effective, the powder has to stay bone dry, so it isn’t the most effective method for a watered yard.

Do not expect immediate results. It will take about ten days to kill adult fleas after they come into contact with the material. More fleas will appear as flea eggs hatch; they too will have to come into contact with the material.

Advantages: Long lasting, low odor, easy to apply, not absorbed into surfaces and is readily picked up by pests, if spilled can be easily cleaned up

Disadvantages: easy to misapply, can become airborne and can contaminate non-target surfaces, must be kept dry, can be inhaled by the applicator and a respirator should be worn, can be abrasive and eye protection should be worn.

Q: Are there any common application errors?

A: If diatomaceous earth or other dusts are applied too heavily they may become “physically” repellent – the bugs just don’t want to rest on a heavily dusted surface or wade through a barrier of dust material. As one industry consultant stated it 30 years ago, “if you can see the dust on the surface after you applied it, IT WAS TOO MUCH.” It is our tendency, and comfort level, to be able to see the result of our application, and we may believe that a nice, even, visible layer is just perfect. In reality, this is an over application and detracts from the effectiveness. Even a nearly invisible layer of the dust allows particles to adhere to the lower surfaces of the bugs that walk over them or rest on them, and sorptive dusts like silica gel also may have an electrostatic charge to them that helps them attach to insects.

There are two huge advantages to using the inorganic dusts like silica gel and DE – extremely low hazard to people and pets and many years of residual effectiveness. As long as they are applied to a dry surface the dust particles remain available to the bugs that touch that surface at some point in time. This is perfect for wall voids and interior voids of equipment or furnishings that are okay for dust to be in. Also appropriate for within around the edges of floors behind molding or carpet edges, and carefully within deeper crevices.

Bottom line is that dusts have an excellent role in control of many structural pests and DE should be non-repellent if it is applied discreetly.

Q: Are any pest control companies willing to use diatomaceous earth and other low toxic, more “natural” pest control treatments?

A: YES! It’s a misconception that all pest control companies push dangerous pesticides. A good pest control company will have technicians that take the time to speak with the customer about the pest problem, the customer’s goals in pest control (including low toxic remedies), and then discuss the different products that meet the customer’s requirements. Additionally, a good pest control company will adhere to integrated pest management (IPM) principles. An IPM approach is focused on the removal of the three key elements pests need to survive: food, water, and shelter. By concentrating on eliminating the sources of these elements, IPM aims to correct the root cause of the pest problem. You gain a longer-term solution to pests in the least intrusive manner possible.

Q: What about boric acid as a flea treatment?

A: Contrary to things you read on the Internet, boric acid is NOT a desiccant and does not kill by plugging the breathing openings on bugs. It is toxic only by ingestion. Unless you and your pets get a boric acid transfusion into your blood stream, it will not work on fleas.  Further, boric acid also is NOT non-toxic, is NOT safe to use around children, is NOT toxic to “all” insects, does NOT attack their nervous systems, is NOT a “drying agent” to insects’ bodies, is not absorbed through their exoskeletons, and is not the “secret” ingredient in professional products. It is a product that the pest control industry uses in specific formulations for specific pests and is applied according to the manufacturer’s label.

Flea Control and Prevention Tips

About the Author:

Garrett Thrasher is Vice President and General Manager of Thrasher Termite & Pest Control of So Cal, Inc., Chairperson of the San Diego District of the Pest Control Operators of California (PCOC), a member of the bedbugFREE network, and a member of the National Pest Management Association. Author of The Bed Bug Battle Plan: Field Tested Solutions for Bed Bug Extermination and Prevention (ISBN: 1500838209), Garrett’s solid understanding of bed bugs, their behavior, current outbreaks, and experience on camera has made him a leading contact for news and media outlets. He is also a sought after speaker on the topic of managing online reviews for positive impact. He has spoken at PestWorld and PestTech, and was featured in PCT Magazine and the PCT Podcast. Thrasher Termite & Pest Control of So Cal is accredited by QualityPro–the mark of excellence in pest management.


  1. […] There is such a mixed sentiment out there about diatomaceous earth, leading to a lot of confusion. People are left wondering if it really does kill pests, and if so, how effective it really is. Learn more about the pros and cons, here. […]

  2. […] about treating fleas yourself with dichotomous earth? Think again. As we’ve mentioned before “natural” is not the same as […]

    • Michelle September 28, 2016 at 2:40 pm - Reply

      My understanding is that diatomaceous earth is nontoxic, there is a type that people ingest purposefully for health reasons. People can eat it. It kills insects by dessication,not poison. Is that your understanding as well? That it dehydrates them by cutting their exoskeleton?

      • Buzz September 29, 2016 at 2:32 pm - Reply

        You are correct that diatomaceous earth kills insects by abrading the wax-like coating on their exoskeletons, thereby leading to desiccation. Because we use diatomaceous earth labeled for pest control, it is a pesticide. Regarding toxicity to humans, we ALWAYS refer to the label. (The label really is the law.) Below is the toxicity section of one brand of diatomaceous earth labeled for use as a pesticide. (The easiest way to obtain details about any chemical or pesticide is to search on the product name and “SDS,” for Safety Data Sheet.)

        11. TOXICOLOGY INFORMATION Summary: Prolonged and repeated exposure to excessive concentrations of this product’s dust, or any nuisance dust, can cause chronic pulmonary disease. Dust contact with eyes may cause temporary scratchiness or redness. This product has not been classified as a carcinogen by NTP or IARC.

        Toxicology Information varies by specific brand and formulation. Some diatomaceous earth products labeled for pest control contain additives. Always read the label.
        FYI: As a licensed pest control operator we must be very careful about using words such as “poison” “non-toxic” and “safe.” Therefore, this long-winded response!

  3. Eric Muss-Barnes May 28, 2017 at 11:31 am - Reply

    You stated: “The most we can say is that diatomaceous earth has low toxicity to humans.”

    This is not entirely accurate. There are TWO TYPES of diatomaceous earth. The kind marketed for “pest control” can be toxic, because it contains other additives. The kind labelled as “food grade” is not toxic and literally edible. The “food grade” version is used to feed farm animals to help their digestion by killing worms and other parasites. It can also assist humans the same way. Obviously, it is vital to know which one you are using. But, again, there are different types of diatomaceous earth and the “food grade” version is 100% non-toxic. If it were toxic, the companies that sell it would have a lot of lawsuits on their hands!

    • Buzz August 18, 2017 at 11:55 am - Reply

      Our statement IS accurate. Licensed pest control companies are prohibited from claiming that any pest control product is safe. The most we can say is that a product is low in toxicity. To say otherwise is not legal or nor prudent for a licensed company. We make no statements regarding any product labeled as food grade.

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