How To Get Rid Of Scale Insects? 8 Easy Methods

Scale sounds and looks like a disease that affects plants, but it is actually an infestation by any of more than 7,000 kinds of tiny sap-sucking insects.

Scale insects feed on sap by sticking to plant stems, branches, and even leaves. They have bumps that look like shells and could be mistaken for fungus or bacteria.

But treating scale is very different from treating plant diseases. If you want to fix the problem, you need to know the difference.

Before Getting Started

Make sure you have a problem with scale before you try to get rid of it. Scale insects, on the other hand, come in many different sizes, shapes, and colors.

They are often a little rounded, but not always. Scales can be white, black, orange, or a colour that blends with the plant, making them harder to see.

Most scale insects are very small, with lengths between 1/16 inch and 1/8 inch. But you will never see just one of them, which makes it hard to miss them. Scale is almost always found in groups.

Unlike other insects, once they have locked themselves into place to pierce the plant and start eating the sap, they can’t move.

If you look at the stems or leaves of a plant and see groups of small bumps that look like shells, you are probably seeing scales. One of the most common signs that a plant has a scale problem is when black mould starts to grow on it.

When scale insects eat plants, they make a sugary substance called honeydew. This honeydew attracts fungi, which grow black mould on some scales but not all. Mold that looks black is one of the most obvious signs of scale.

Their armoured scales make a hard shell around their bodies to protect them from being eaten. The shell also makes it hard to use pesticides because they can’t reach the insect inside.

Different kinds of scale insects are like different kinds of plants. Euonymous bushes often have problems with scale. Scales also often attack magnolia and fruit trees.

Mealybugs are common garden pests that belong to the family of soft or unarmored scale insects. They are a bit bigger than other scale insects, which makes it easier to tell them apart from diseases.

When to Combat Scale

Control methods work best during the “crawler stage” of the scale insect, which is when the nymphs come out soon after the eggs hatch. Now that they have legs, the nymphs are crawling quickly to find new places to attach and eat.

At this point, insecticides might be able to kill them. But time is very important, and the window of opportunity is very small.

Scale insects may be hard to get rid of because they are so attached to their host plant and have a tough shell around them. It is often easier to just throw away contaminated plants than to do all the work needed to get rid of the scale.

If you get rid of the scale quickly, it might not be able to move to other plants. If this is not possible, there are other ways to get rid of scale that have been shown to work.

Scale insects in the garden can be gotten rid of in a number of ways, but the best way is to prevent them or get rid of infected plants before they spread.

You might not need to do all of these things to get rid of scale insects, but you might need to do a mix of them.

Prune

If you find the infection while it’s still light, cutting off the infected branches is often the easiest and most effective way to fix it.

Carefully check the plant and any other plants nearby to make sure that all of the contaminated stems have been cut off.

Don’t put infected plant parts in the compost pile. Instead, put them in bags and throw them away or burn them safely.

Treat With Rubbing Alcohol

If the number of scale insects is small, rubbing alcohol could be used to kill them. The best way to get rid of scale bugs is to use a cotton swab to put rubbing alcohol directly on them.

This could take a long time in a garden outside, so put one part rubbing alcohol and seven parts water in a garden sprayer or spray bottle.

Do this every two to three days until the bugs that are causing trouble are gone.

Spray With Horticultural Oil

What is horticultural oil?

In late spring, just before the leaves come out, it’s helpful to spray your plants with horticultural oil. Scale insects might spend the winter as young insects or eggs in the bark of trees.

At this point, spray your plants with 2 to 5 ounces of oil per gallon of water in a hose-end sprayer or garden sprayer. This treatment will kill the insects before they can make a protective layer of scale.

Scale can be found on the stems, the undersides of leaves, and at the plant’s base, so the whole plant needs to be treated. The scale insects die because the oil covers them and blocks their breathing holes.

Tip

The best way to use horticultural oils is with a hose-end sprayer, which makes the oil last longer and cover a wider area.

Apply Insecticidal Soap

Even though insecticidal soaps can be used to kill scale larvae, they don’t work once the insects have attached themselves and are eating behind their hard shells. Use a spray bottle or garden sprayer to cover the leaves until they are all wet.

One ounce of soap per gallon of water is a good rule of thumb, but check the directions on the package to be sure.

Because these soaps don’t last long in the environment, you will have to use them more than once to catch all of the larvae. However, these organic insecticides won’t harm the environment in any way.

WARNING

If you use soap that kills insects on plants that don’t have enough water, you could hurt them. Also, you should never use the product on plants that are in direct sunlight or when the temperature is above 90 degrees Fahrenheit.

Apply Neem Oil

Neem oil or insecticides with azadirachtin, which is a big part of neem oil, are good at preventing scales and killing insects, not just the larvae.

Since neem oil doesn’t mix well with water, you should add a small amount of dish detergent to act as an emulsifier.

One to two teaspoons of detergent and one to two tablespoons of oil should be added to a gallon of water. To put it on, use a garden sprayer.

Neem oil and other treatments with azadirachtin are considered organic insecticides and are safe for honey bees and most other good bugs. Other insecticides made from plants may also work.

Use Beneficial Insects

You can help these animals by giving them food and a place to live. You can also order insects that are good for your garden and have them sent to you by mail.

WARNING

Pesticides made from chemicals should only be used as a last resort to get rid of scale.

Even though systemic insecticides like neonicotinoids (acetamiprid, dinotefuran, imidacloprid, and thiamethoxam) are sometimes effective, it is now known that these chemicals are very dangerous for honey bees and other pollinators.

If you have tried everything else, use a chemical pesticide.

Controlling Scale on Indoor Plants

Since there are no natural predators inside, scale insects will multiply much more quickly. When scale gets into indoor plants, you have to be very careful to get rid of or control it.

If you notice the problem early enough, you might be able to fix it by cutting off the stems that are hurt. Keep a close eye on the plant for a long time to make sure no new scales come out. Take the cut stems off as soon as you can.

Scale on houseplants can be removed by wiping them gently with a sponge made for the face or a cotton swab soaked in rubbing alcohol.

Even though the alcohol should kill the scale, the dead insects will stay on your plants, making it harder to check for new infestations.

There are small face sponges in the cosmetics section that are rough but not too rough to scratch the plant stems.

Make sure you pick simple sponges that don’t come with any lotion or cleanser. As with any test, start with a small area because some plants are more sensitive than others.