What Pests Does Diatomaceous Earth Kill?

Diatomaceous earth (DE) kills a wide range of pests, including bed bugs, fleas, cockroaches, ants, mites, ticks, and silverfish. This natural, chemical-free powder is made from fossilized algae and works by piercing the exoskeletons of insects, causing them to dehydrate and die. However, it must be applied correctly to be effective.

DE is an affordable pest control option (typically $10–$25 for a 10-pound bag) and is safe for pets and kids when used properly. In this guide, I’ll explain how DE works, what pests it kills, and the best ways to apply it while avoiding common mistakes.

What Is Diatomaceous Earth?

Diatomaceous earth is created from the fossilized remains of phytoplankton, an ancient aquatic microorganism.

DE is found naturally in sedimentary rocks and is mined for use in a variety of products, such as organic insecticides, cosmetics, toothpaste, swimming pool filters, industrial products, pharmaceuticals, and food products. Visually, diatomaceous earth is a fine white powder that feels smooth to the touch.

Food-grade diatomaceous earth is nontoxic to fish, birds, aquatic invertebrates, and other wildlife, making it a safer pesticide option than traditional pesticides. In contrast, industrial-grade diatomaceous earth has a stronger silica concentration, making it toxic to some mammals.

What Pests Does Diatomaceous Earth Kill?

Diatomaceous earth works by piercing the exoskeleton of insects. The diatoms, or phytoplankton in DE have tiny, strong shells made of silica, one of the hardest natural substances on Earth. The sharp edges of the silica cause hundreds of abrasions on insects with exoskeletons, causing irreparable damage. Once the insects’ exoskeletons are pierced, they dry out and pass away.

As a result, you can use diatomaceous earth against any insects with exoskeletons, such as roaches, crickets, or centipedes.

Diatomaceous earth kills a huge variety of pests, including:

• Bed bugs
• Cockroaches
• Slugs*
• Centipedes
• Millipedes
• Snails*
• Crickets
• Moths
• Fleas
• Lice
• Beetles
• Sow bugs
• Pill bugs
• Twig borers
• Mites
• Thrips
• Ants
• Termites
• Armyworms
• Fungus gnat larvae
• Aphids
• Ticks
• Fruit flies
• Spiders
• Silverfish
• Earwigs

*DE doesn’t directly kill Snails and slugs, but it’s a huge deterrent for them because it’s uncomfortable for them to crawl over, and it slows them down. As a result, you can use DE as a deterrent or barrier against slugs and snails.

For diatomaceous earth to work, it has to come into direct contact with the insect or critters. As a result, pollinators, ladybugs, and other beneficial insects are typically safe if DE is only applied on the ground and not near flowers or plants frequented by pollinators.

If bees or other beneficial insects come into contact with DE, it will pierce their exoskeletons and kill them, so keep this in mind when placing DE in your backyard.

Diatomaceous earth doesn’t affect certain insects, like caterpillars and earthworms, because of their thick outer mucus layers, which aid them when they travel through gritty soil. As a result, you can safely use DE in a worm compost bin.

Is Diatomaceous Earth Dangerous for Humans?

Diatomaceous earth (DE) is considered safe for use around mammals, wildlife, and humans because it’s pure silicon dioxide, which is non-toxic and found in many items at your local grocery store. DE can be found in makeup, pool filters, grain storage products, and alcohol filters.

However, when applying DE, you should wear a dust mask because inhaling DE is unhealthy for animals and humans. The fine dust particles may cause respiratory issues, especially after long-term exposure. You’ll also want to be extremely careful not to get diatomaceous earth in your eyes because it could scratch your cornea.

How To Apply Diatomaceous Earth

The simplest way to use DE in your garden is to sprinkle it on the soil’s surface, under potted plants, and anywhere else you spot pests. Avoid applying diatomaceous earth too close to flowering plants that pollinators visit because DE can kill these beneficial insects. Also, don’t dust DE directly onto plants, as this will harm bees and pollinators.

The best time of day to apply diatomaceous earth is during the evening when pollinators are less active. You’ll also want to wait to use food-grade DE until the wind dies down so the powder doesn’t spread.

Finally, keep in mind that diatomaceous earth is rendered almost ineffective when it gets wet. As a result, wait until plants and soil are dry to sprinkle DE on top. Don’t apply DE immediately after it rains or you’ve watered your plants, as this is a waste of product. Typically, you’ll want to use diatomaceous earth weekly until the pest infestation is under control.

What Happens to Diatomaceous Earth in the Environment?

DE is generally considered to be environmentally friendly due to its natural origin and non-toxic nature. When applied outdoors, diatomaceous earth eventually breaks down and becomes part of the soil.

In the environment, DE behaves much like naturally occurring silica or sand. It doesn’t chemically react with other substances or leave harmful residues. Rain and wind will gradually disperse DE, integrating it into the surrounding soil. This process is entirely natural and doesn’t pose any significant environmental risks.

However, it’s important to note that while DE is safe for soil and water systems, its effectiveness as a pest control agent diminishes when it gets wet. This is why reapplication is often necessary after rain or heavy dew.

When used responsibly, diatomaceous earth is an environmentally sound choice for pest management that doesn’t contribute to long-term ecological harm. That said, one environmental consideration to keep in mind is the potential impact on beneficial insects. As mentioned earlier in the article, DE can harm any insect with an exoskeleton that comes into direct contact with it. Apply it carefully in order to minimize unintended effects on helpful garden inhabitants like ladybugs or ground beetles.

So, Is Diatomaceous Earth a Good Choice for Your Yard?

Diatomaceous earth is a simple, natural product that’s helpful for insect control. It’s especially helpful if you’re concerned about using traditional pesticides that are not natural or organic in your garden. This method is the ideal alternative to more toxic pesticides, typically safe for use around pets and children.

Once the pest problem is under control, start taking measures to prevent pests from returning. Prevention is always easier than dealing with a pest infestation, so take steps to change your background environment, seal cracks and crevices where pests may be entering your home, and add plants that are natural deterrents to pests to your garden.

If all else fails, consult with a pest control professional to have your home treated and assessed for potential shortcomings attracting pests to your home and garden.