Diatomaceous Earth for Arizona Bark Scorpions: Not Recommended.

By Georgia A. Clubb, Pest Science Group

Diatomaceous Earth, for Arizona bark scorpions is not recommended. Our concern is especially strong when it is applied around a house like a moat or spread across indoor floors. While it’s often considered a natural product, natural doesn’t mean safe, nor does it mean effective.

This is my professional opinion, based on decades of service, actual use and the results I have seen. My work with Arizona bark scorpions spans 1999 through 2026. That includes professional use of diatomaceous earth and personal use on my own properties that started with high scorpion pressure.

Through my work at Seal Out Scorpions, I have also worked with several thousand clients who had used diatomaceous earth, or DE, without getting the results they wanted. Among those clients, the vast majority eventually discontinued using it for scorpions.

DE was already part of what these clients had tried. They still needed help. That experience, together with my own use of the product with what I felt was failed results, is why I do not recommend it.

I’m sure it could potentially have value for other uses. I just don’t find it for scorpions.

What this opinion is based on

I am not aware of published field studies that test DE for Arizona bark scorpions across multiple occupied homes with different construction, landscaping, irrigation, seasonal conditions and levels of scorpion pressure. Those are the conditions we work with.

I am not presenting my service history as a controlled study. I am explaining what I have learned through decades of working with this problem, using the material myself and seeing the results on clients’ properties.

I still have to make recommendations for the people who need help now. For me, the question is whether I would advise a homeowner to rely on DE as part of a layered strategy for their scorpion problem. Based on that experience, my answer is no.

A line of powder is not scorpion control

DE acts through contact with the pest’s outer surface. It absorbs protective oils and fats, increasing water loss. That is how it kills susceptible pests. It is not an immediate physical barrier that closes an opening or prevents a scorpion from entering a home. It does not work immediately. [1, 2]

Arizona bark scorpions climb walls, can travel across ceilings and use narrow cracks and building voids. A line of powder on the ground does not account for all of those routes and protected spaces. [3]

Even when a scorpion crosses or stilts over the powder, how much stays on it? Is that contact enough to affect it before it reaches the inside of the house? The amount of white powder one can see does not answer either question.

I am also concerned about what happens when a scorpion avoids an application. A change in direction is not the same as control. With an animal that climbs, I would want to know where it went next, including whether it found a route around or above the treated area.

This is why I do not look at a powder line and assume the home is protected.

More product does not mean better results

Mounds around a foundation and heavy applications across floors are part of what concerns me about how DE is used. Adding more powder does not tell us whether we are solving the problem or possibly creating a new one.

Even the product directions do not support that approach. The EPA-accepted Harris DE label calls for light, uniform application and tells users to avoid exposed deposits and introducing dust into the air in living areas. The scorpion directions on the Perma-Guard D-20 label call for light dusting at potential entry locations. These are directions for those specific products, not for every bag of DE. [4, 5]

Outdoor conditions matter too. DE needs to remain dry and undisturbed for its drying action. Irrigation, rain and activity around the property can change the condition of the application. Living in Arizona does not mean the ground beside a house stays dry. [1]

Food grade, pool grade and pesticide products

Food-grade DE without pesticide labeling is not something I recommend for pest control. The National Pesticide Information Center warns that those products may not have been evaluated for pest-control risks or effectiveness. “Food grade” does not mean safe to breathe, and it does not provide directions for treating a home for scorpions. [6]

Pool-filter DE should not be used as a household pest treatment. Heat processing can increase crystalline-silica content, and respirable crystalline silica is a known human carcinogen. That is a specific inhalation hazard, not a reason to call every type of DE carcinogenic. [7, 8]

DE sold as a pesticide is still a pesticide. Some DE-containing products have scorpion directions, and some contain other active ingredients. For example, the Perma-Guard D-20 label lists pyrethrins and piperonyl butoxide along with DE. The results or directions for that mixture cannot simply be assigned to a bag of plain DE. [5]

A label tells us how a particular product may be used. It does not mean there will be meaningful protection and my experience is it often doesn’t meet an expectation.

The dust is another concern

DE can irritate the nose and eyes, and breathing large amounts can cause coughing and shortness of breath. Settled powder can become airborne again through fans, vacuums, doors and foot traffic. Children and pets also spend time close to the floor or ground where the material has been applied. [1, 6]

I do not think residents should live with powder across their floors while they are still dealing with scorpions. We should be considering what the application accomplishes and what people and animals are being exposed to.

Calling it natural does not mean safe.

“It worked at my house”

Someone may apply DE and see fewer scorpions. But what else changed?

Did the weather cool down? Did they start searching for and removing scorpions? Was another treatment being used? Did irrigation change? Were they checking the same areas as often as before?

Arizona bark scorpions are less active during cooler periods, and irrigation, extreme heat and disturbance can change their movements. Timing can make a product appear more effective than it was. [3]

DE may have contributed to an improvement, but it could have also been from other variables. But seeing fewer scorpions after applying it does not, by itself, tell us why or where they are rerouted to. Nor does it tell us whether the same approach will work on a property with persistent, heavy scorpion pressure.

That is the problem with recommending something based only on “it worked at my house.” My recommendation comes from my own use and years of working with clients who had already tried it without getting the control they needed.

Treat the problem, not just the latest sighting

I look at pest management much like healthcare. The property is the patient. We need to understand what is happening, why it is happening and what will change the outcome.

Pesticides should be treated with the same care we expect with medication. What are we treating? Is the product appropriate? How is it being used? What are the risks? Is it producing the results we need?

Being able to buy something over the counter does not make it the right treatment. Reapplying it every time another scorpion appears can keep a homeowner focused on the latest sighting without understanding why scorpions keep entering.

If the result is more powder, more exposure and the same scorpion problem, I do not consider that an acceptable outcome.

My recommendation

After decades of service, personal use and work with clients who had already tried DE, I do not recommend it for Arizona bark scorpion control. I am particularly opposed to powder moats around homes and broad applications across indoor floors.

That is my professional opinion from actual use and results. I want residents to understand the basis for it, rather than assume it comes from a preference for one product over another.

The goal is scorpion control and peace of mind for the people living in the home. That is the result I expect a treatment plan to deliver.