Will Diatomaceous Earth Kill Scale Insects?

Scale insects feed on the sap of plants that can weaken, damage, and kill indoor and outdoor plants. So, how can you prevent or get rid of such insects? We researched to find out if Diatomaceous Earth is a viable option. With that said, let's check this out below!

Diatomaceous Earth is excellent for killing scale insects and preventing them from attacking your plants in the first place.

Keep reading to learn how Diatomaceous Earth works to kill scale insects. We have included the pros and cons and discussed ways of identifying this insect and how it can damage your plants. We'll also discuss how to prevent the scale insects from infesting your plants. Let's begin!

Gardener white sprinkle Diatomaceous earth( Kieselgur) powder for non-toxic organic insect repellent on salad in vegetable garden, dehydrating insects. - Will Diatomaceous Earth Kill Scale Insects?

Can Diatomaceous Earth (DE) Kill Scale Insects?

Gardener white sprinkle Diatomaceous earth( Kieselgur) powder for non-toxic organic insect repellent on salad in vegetable garden, dehydrating insects.

Unlike insecticides that use chemicals to kill insects, Diatomaceous Earth is a mechanical killer. It is available in powder form and made from crushed algae fossils.

These fossils build up over time, forming sediments harvested from rivers, oceans, or streams.

The crashed fragments from these fossils are very sharp. So, when the insects crawl on the powder, it tears their outside covering, hydrating them until they die within 48 hours.

You can apply DE in two ways, which are explained below:

Dusting DE

Check out this powder duster on Amazon.

You can apply the Diatomaceous Earth on top of the soil and around the base of each plant. Suppose you have potted plants and dust underneath the pots. To apply evenly, use a garden duster or a flour sifter.

However, it's good to note that DE can harm the bees, which play a vital role in the ecosystem's survival. But, since they do not buzz around the plants in the evenings, this is the best time to apply the DE.

Spraying DE

To spray many plants on every corner and crevice of your plants, you can mix the powder with water. Mix 4 to 6 tablespoons of DE with a gallon of water.

Pour this mixture into a spray bottle and spray it onto the plants. Occasionally shake the bottle to prevent the powder from separating from the water.

Wait for the DE to dry, as it cannot kill insects when it is wet. After drying, the powder will remain on the plant.

Benefits And Drawbacks Of Diatomaceous Earth

Diatomaceous earth( Kieselgur) powder in jar for non-toxic organic insect repellent. Using diatomite in garden concept.

Diatomaceous Earth is a non-toxic substance that you can use to kill insects instead of using a chemical insecticide.

Although it is a natural product, there is still ongoing debate about it, including the pros and cons, which are the following:


The pros of DE include the following:

Safe To Use

The Food & Drug Administration considers DE as generally safe.

In addition to being used as an insect killer, it is used to manufacture various other products such as toothpaste, certain foods, beverages, paint, etc. Therefore it is not hazardous to humans or pets.

It kills Many Types Of Insects & Pests

Besides getting rid of scale insects, DE effectively kills other insects that love feeding on plants, thereby destroying them.

Therefore, if other stubborn insects feed on your plants, such as beetles, worms, and snails, you can eliminate them using this powder.

Continually Effective

DE remains continually effective, though this depends on the powder remaining dry. Unlike insects building immunity against chemical insecticides, insects cannot build immunity against DE.


The cons of DE include the following:

It Can Be Harmful If Inhaled

Despite DE not being harmful to humans, pets, or children, it can be detrimental to your health if inhaled in large quantities. It can irritate your sinuses. Besides, dust particles can irritate your eyes and the skin.

Works Only When It Is Dry

The DE becomes ineffective when it is wet. Thus, you can't use it during the rainy season; you must wait until it's over.

How To Use Diatomaceous Earth

See this Diatomaceous Earth on Amazon.

The best time to start treating your plants with Diatomaceous Earth is when the insects crawl, looking for a spot to attach themselves to the plant.

But, if you only notice a few scales on your plants, you can start treatment by manually removing the scales. Dip a cotton swab or soft toothbrush in 70% isopropyl alcohol or soapy water and gently wipe the insects off the plants.

Alternatively, you can cut off the affected parts of your plants or pull out entire plants. Afterward, dispose of them far away from your plants to prevent the scales from spreading to other plants.

Spray or sprinkle the DE on your plants if there is a large-scale infestation. A more effective way of getting rid of these insects is by applying the DE before they appear.

If DE fails, you may opt for other methods, such as organic insecticidal soap like the one shown below.

See this insecticidal soap on Amazon.

How Do You Find Scale Insects On Plants?

photo shows a closeup situation of two scale insects sucking on a branch of lime or citrus tree

You may not easily identify the scale insects. This is because they are so tiny and may confuse with a disease or another problem. The scale insects can camouflage, making it difficult to notice them on the plants.

However, there are ways you can spot scale insects, including:

Mass Of Tiny Bumps

If you notice a mass of tiny bumps on sections of your plants, they are likely the scale insects.

Black Mold

If there are patches of black sooty mold on your plants, it could be scale insects. The insects excrete a substance called honeydew, on which a black mold grows.

There are many other insects capable of producing honeydew. That is why it is good to ensure you know from which insect the honeydew is coming.


During the larvae stage, the scale insects can move about, but after this stage, they are immobile. Due to this fact, you can identify the larvae by placing a white paper under the plant and then shaking it.

They should fall onto the paper. Use a magnifying glass to confirm they are the ones.

You can also stick tape to the affected parts of your plant, remove it and then check if the insects are scale.

Discoloration On Leaves

Leaf discoloration is one of the first signs you will notice on your plants when the scale insects attack your plants.

What Damage Do Scale Insects Do To Your Plants?

A small brown slug eats the leaves of the plant. Pests eat radish leaves. slug invasion in spring.

Scale insects suck the sap out of the plants, stealing the nutrients needed for a healthy growing plant.

If you don't address this problem early, the insects will continue sucking the sap causing the plant's leaves to drop, wilt and turn yellow.

As the insects continue to feed from the plant, your plant will stop growing. In addition, the branches will start dying, the bark will crack, and your plant will eventually die.

Also, if you notice a sooty mold or black sticky substance on the leaves or branches, it indicates damage to your plants has begun. This creates a problem because mold prevents photosynthesis from taking place.

How To Prevent Scale Insects From Attacking Your Plant

You desire your garden or indoor plants to grow healthy. Besides killing the scale insects using Diatomaceous Earth, it is also a good idea to prevent them from attacking your plants in the first place.

You can achieve this by following these steps:

Maintain Healthy Plants

A healthy plant can resist diseases and insects. Therefore, keep your plants as healthy as possible by watering them adequately during summer and ensuring they receive enough sunlight.

This prevents excessive heat from adversely affecting plants.

Keep Your Garden Clean

Regularly weed and remove debris from around your plants, keeping away insects. Remove fruits that fall near your plants. This is because fruits are a good breeding ground for insects.

Plant Some Insect Resistant Species

Before growing new plants in your garden or indoors, look for species resistant to the scale insect; in addition, carefully examine the plants before purchasing them to ensure they do not have any iota of scale infestation.

Examine Plants Often

Check your plants often for any sign of scale insects. Look for them in their favorite hiding place, under the leaves, and in the stem joints.

To Finish It Up

Gardener white sprinkle Diatomaceous earth( Kieselgur) powder for non-toxic organic insect repellent on salad in vegetable garden, dehydrating insects.

Scale insects can damage your plants, eventually killing them. To prevent this from happening, you can use Diatomaceous Earth to kill the insects. It is natural and safe to use on plants.

We have discussed how these insects can damage your plants and how to identify them. Finally, we have provided ways of preventing them from attacking your plant.

And while we have your attention, here are some related garden articles:

When To Apply Diatomaceous Earth

how To Get Rid Of Black Aphids

Will Diatomaceous Earth Kill Scale Insects?

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