Scale Insect Control: How to Identify, Prevent and Get Rid of Scale Insects

Scale insects may be small, but they are a huge threat to garden plants, including those that you grow indoors. They suck on their host plant, depriving it of the essential nutrients that are necessary for healthy growth. To prevent severe infestation, it is important to arm yourself with the right knowledge on how to get rid of scale insects.

The appearance of scale insects will vary depending on their specific type. In the case of hard scale insects, they have a hard and detachable shell that acts as their covering or armor. The average length is 1/8 inch. On the other hand, in the case of soft scale insects, the length is usually ½ inch. They have a soft and cottony cover that hides their body. Both of their protective covers will look like bumps or shells. Their cover gives them an odd look and many people often think that they are not pesky pets.

Group of Scale Insect

Group of Scale Insect on the Tropical Plant

Scale Insect’s Habitat

In Canada and the United States alone, there are more than 1,000 species of this pest. They often thrive on the sap of their affected plant. They are also common in branches, twigs, fruits, and leaves of their host. This is where they suck to extract the nutrients, which will make the plant weak. Aside from the garden, other common places where you can find scale insects are near seashores, shrubland, orchards, mountain, and lowland forests.

Identifying Scale Insect’s Damage

Plants Affected

Because of the diversity of the population around the world, scale insects infest a wide array of plants, both in the garden, indoors, in greenhouses, and in forests, among others. Plants that are unhealthy and poorly maintained are the ones that are more susceptible to infestation. Ornamental shrubs, fruit trees, and interior plants are some of the most common hosts.


The following are some of the most common indications that will provide you with a clue of the presence of scale insects:

  • The discoloration of the leaf is one of the first signs of infestation. Because of sucking, the leaves do not receive the nutrients that it needs. It makes the surface yellowish, and eventually, it will fall off. In severe instances, all the leaves will fall and this results in defoliation. It is not just unattractive, but also one of the reasons why the plant will die.
  • The presence of honeydew is another thing that you should watch out for. It results in the production of sooty mold. Soft scale insects excrete a large amount of sugary and sticky substance, which adheres on the host plant. It looks like black mold. It covers not only the leaves of the plant, but even its stems. It creates not only aesthetic damage, but also inhibits photosynthesis, and hence, causing more serious problems to the host.
  • In a general sense, scale insects will lead to the loss of vigor of the plant. As it weakens, it begins to dry and may not develop flowers or fruits.

Results of Infestation

Because they suck the nutrients that are essential for the survival of the hosts, the most common result of infestation is the death of the plant. This is especially the case when the scale insects attack while the plant is still young and unable to defend itself against pests. Because of this, they are also more prone to injuries and diseases.

Leaves Discoloration

The Discoloration of Leaves is One of the First Signs of Infestation

How to Get Rid of Scale Insects

Natural and Organic Solutions

Here are some of the best ways to eliminate scale insects in a manner that is natural and effective:

  • The removal of the scale insects by hand is one of the first things you can consider. It may not be the most convenient, but it is effective, especially for small population. Spray water on the plant first and use a brush to scrub the surface where the insects are present. Handpicking is also possible if they are large enough. Be sure to throw them in soapy water solution to kill the pest.
  • Pruning is another solution that works. If you notice symptoms of infestation in one part of the plant, trim it right away. This will prevent damages on the healthier part of the plant. It also opens up the canopy of trees, making it easier to spot and kill scale insects.
  • You can also resort to the use of biological controls. There are many predators that you can buy or attract in the garden. Rather than manual removal of the scales, the predators will do such job. Metaphycus and Coccophagus, which are forms of wasps, are some of the most effective. When it comes to ladybugs, meanwhile, Rhyzobius is one that can yield the best outcomes.
  • The use of tape traps is another simple solution that might work. You can wrap it around the bark of the affected tree. You can also lay it on the surface of the host plants. The sticky surface will make sure that scale insects will not escape once they are trapped. Throw the tapes in proper bins to avoid the scales from going back to its host.
  • Another method that can be effective is the use of horticultural oil. This can be an excellent alternative to pesticides with harsh chemicals. The good thing about these oils is that they kill scale insects of all stages, including those that are already adults.

Chemical Solutions

If the solutions above do not work, your last course of action is to use chemicals. As much as possible, stay away from this control and elimination measure as these chemicals contain toxic ingredients that can harm the environment in several ways. You can use systemic insecticides, which you will have to apply on a specific part of a plant. Regardless of what you will use, pay attention to the list of the active ingredients and the instructions for correct application.

How to Prevent Scale Insects

When it comes to preventive measures, there is perhaps nothing that is as effective as providing the plant with tender loving care. From watering to fertilizing, you should exert effort to make sure that your plant grows in the healthiest state possible. When it is healthy, there is a lesser likelihood that it will be a target of infestation. Wrapping the trunk of the tree with a band is also a good step to prevent injuries in the bark. Lastly, early detection of the problem is also necessary. With this, you should periodically inspect your plants for symptoms of infestation. The sooner you act, the easier it is to manage the problem.

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