Diatomaceous Earth For Aphids: How To Use | How It Works

Both Diatomaceous Earth and Aphids have quite a reputation. Aphids are vampires in the plant world.

They suck the sap from your plants and leave their sticky substance waste, honeydew.

Leaves affected by aphids insect pestsPin
Diatomaceous Earth will kill soft bodied aphid pests | mikrostoker-DepositPhotos

Finding a plant with an aphid infestation is a serious matter. You will want to address the problem ASAP to avoid other issues. That is where diatomaceous earth comes in.

In this article, we’ll provide an in-depth look at aphids and diatomaceous earth and answer the most common question: will diatomaceous earth kill aphids?

Why Aphids Are Bad

Aphid honeydew leads to black soot or other dangerous problems. The aphids themselves won’t kill your plants, but they cause other problems.



Aphids tend to attract sick plants. They often bring other pests, such as ants, which use aphids as cattle.

When your plant has an aphid infestation, you can be sure of a few things:

  • Your plant is sick or has some damage.
  • It has yellowing or curling leaves.
  • You may also notice distorted plant growth.
  • Expect other pests, such as ants, and beneficial predators, such as ladybugs.
  • Adult female aphids give live birth to nymphs, which are often already pregnant. So expect a rapid aphid population explosion.
  • Infested plants will become more susceptible to a wide range of bacterial and fungal infections.

What Is Diatomaceous Earth?

Diatomaceous earth (also known as diatomite or DE) is a natural, mined product. Food grade DE is safe around children and pets.

Diatomaceous earth is a form of sedimentary rock found along waterways. This rock contains the fossilized remains of diatoms – microscopic organisms rich in silica.

The best form is food-grade diatomaceous earth, which crumbles into a fine white powder.

This organic pest control is harmless to larger animals. But, diatomaceous earth is deadly to insects, arachnids, and other tiny garden pests.

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How Does Diatomaceous Earth Kill Aphids?

First, let’s answer the question, “Does DE Kill Aphids?” The answer is YES!

The secret to how diatomaceous earth and aphids work is less of a mystery than it might first seem.

The diatom shells within the powdered rock are too small to harm larger animals. But, the shells are big enough to affect soft-bodied bugs like spider mites, green peach aphids, slugs, and snails.

When a crawling insect comes in contact with the powder, the sharp edges of the diatoms lacerate the waxy coating on the insect’s exoskeleton.

The lacerations cause moisture to escape the insect’s body. The pests then dehydrate and die.

The good news is that you can use food-grade DE to kill several pests, including:

  • Ants
  • Aphids
  • Bed bugs
  • Cockroaches
  • Earwigs
  • Fleas
  • Lacewings
  • Silverfish
  • Slugs
  • Spiders

How long does it take diatomaceous earth to kill aphids?

Diatomaceous earth can kill aphids on contact. When the aphids come into contact with the diatomaceous earth, the sharp particles pierce their bodies, causing them to dehydrate and die.

The time it takes for diatomaceous earth to kill aphids can vary depending on various factors, such as the infestation’s severity and the application’s effectiveness.

In some cases, aphids can be eliminated within a few hours to a few days after applying diatomaceous earth

The bad news. DE for aphids will also kill beneficial insects such as ladybugs and pollinators. Keep this in mind when using Diatomaceous Earth.

Avoid using DE on blooms or garden plants that attract monarch butterfly larvae. The diatomaceous earth could kill the caterpillars.

Instead, you can use another natural alternative, which is neem oil spray. Just mix neem oil and water in a spray bottle, and you’re all set.

You can add 2 tablespoons of neem oil, 1 tablespoon of mild liquid or insecticidal soap, and a gallon of warm water.

Planting natural aphid repellants is also a great alternative. Plants include catnip, chives, allium, garlic, dill, fennel, and onion.

Related: How To Get Rid of Tomato Aphids

How To Use Diatomaceous Earth to Kill Aphids

Start by sprinkling Diatomaceous Earth on the soil around your affected plants. When using it for aphid control, the DE creates a barrier against ants or other insects.

Goggles or a face mask are not necessary but help prevent any of the dust from getting in your eyes or nose.

For the plants themselves, you can either spray or dust DE to kill the aphids already infesting them.

There are several dusters on the market.

You can even use an old makeup brush. Lightly dust the leaves and stems and any other exposed parts of the plant. Dust again after each rain.

As aphids prefer to feed on the underside of leaves, a powder sprayer may be preferable.

These allow you to apply puffs of DE onto the plant at almost any angle.

How Fast Does Diatomaceous Earth Kill Aphids?

Diatomaceous earth on aphids isn’t an instant killer. You will have to use some patience when dealing with a large infestation.

DE will have a more noticeable effect once the aphid population begins to shrink.

More Uses For Diatomaceous Earth

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