Harlequin Bug Control: How to Identify, Prevent and Get Rid of Harlequin Bugs

Both in home gardens and commercial fields, harlequin bugs can spread infestation, making it a significant concern amongst gardeners and growers. Their appearance might seem attractive, but they can wreak havoc that is beyond what you can imagine. With this, knowing how to get rid of harlequin bugs is necessary to avoid excessive damages.

Harlequin Bug

Avoid excessive damages caused by harlequin bugs

Harlequin bugs lay their eggs on the leaves of the host plant. They are tiny and barrel-like with color that ranges from white to yellow. In their nymph stage, they are round and black with pale green spots. During this stage, they undergo five instars before reaching full maturity. When they are adults, their body looks like a shield with an average length of 3/8 inch. You will easily notice these bugs because of their bright colors. The color patterns will vary depending on the season they appear. They can be black and red or black and yellow.

Harlequin Bug’s Habitat

This specie is native to Central America and Mexico. The first record of its appearance was in 1864 in Texas. When they are in the egg form, they will cling to the underside of the leaf. In their adult stage, they are inactive during the winter months. They start being active in spring when the temperature starts to increase. They can attack the different parts of the host plants, but most of them will appear on the leaves and stem. This will depend on the specie of the host plant. They can be a problem in small gardens at home and even in huge agricultural fields.

Identifying Harlequin Bug’s Damage

Plants Affected

Cole crops, specifically crucifers, are the most common host plants for harlequin bugs. Some that are most susceptible include cabbage, cauliflower, broccoli, arugula, horseradish, and collards. There are also other crops wherein they can be present, such as in potato, squash, pea, tomato, pear, raspberry, peach, grape, and beans, among others.


Pay attention to the following symptoms, which will be indicative of the presence of harlequin bugs:

  • Harlequin bugs have a mouth that resembles sharp needles. With this, one of the most common signs of their presence is the unattractive appearance of the leaves. They can chew it, especially the edges.
  • The appearance of stipples is another common symptom you should watch out for. This refers to the dot-like patterns that you can find in the flower of the host plant.
  • The leaves will also exhibit signs of discoloration. It will develop a brownish color and will appear tattered.
  • If you notice that the plant is wilting, this can also be an indication that harlequin bugs are present.

Results of Infestation

Plant stunting is one of the most common things that happen as a result of the infestation of harlequin bugs. The appearance will depend on the plant, but in most cases, it will be shorter than the usual. The loss of vigor is another thing that can happen. With the presence of harlequin bugs, plant wilting will also be common. Eventually, the plant will die because of the loss of the beneficial nutrients for its healthy growth. This is especially the case with younger plants. When the plant is mature enough, on the other hand, it may be more resistant to damages.

How to Get Rid of Harlequin Bugs

Natural and Organic Solutions

Elimination and control of harlequin bugs will be possible through natural methods, which are safe and effective. The following are some of the best things to do:

  • For most people, hand-picking is one of the most common technique. It is important to do this while they are still in the form of eggs. Take them out of the host plant before they hatch and become destructive. If they are already adult bugs, throw them in soapy water, which will kill them. Avoid crushing the bugs as they will release a stinky odor.
  • You can also ask help from animals and insects. Rather than manually spotting the harlequin bugs and taking them out, you can take advantage of beneficial birds, wasps, and insects. Parasitic wasps are some of the most popular. They will work tirelessly to help effectively get rid of the pests. Planting herbs and wildflowers is one of the easiest ways to attract such wasps in the garden.
  • The use of row covers is another measure that is simple, but can yield a high level of effectiveness. Lacing covers on the top of the plant will offer the protection that it needs. However, this is best only for plants that do not require pollination for their survival.
  • Using kaolin clay also holds a lot of promise. While it is popular as a product for the skin, it can also be effective for pest treatment. It is a natural mineral that creates a protective barrier to keep the harlequin bugs out of the plant.
  • You might also want to consider using an insecticidal soap, which is better than using solutions with toxic chemicals. This will penetrate the shell of the harlequin bugs, which will make them weak, and eventually, they will die.

Chemical Solutions

Pesticides containing chemicals are popular amongst commercial growers, which can present an effective solution for large-scale infestation. Using chemicals, however, can harm the environment and other insects. Professional application is necessary, as well as the use of protective gear. This will make sure that there will be no hazards. Some of the most popular chemicals that can yield a high level of effectiveness include organophosphates and pyrethroids. There are also some chemicals that you can apply to the soil to control harlequin bugs, such as neonicotinoids.

How to Prevent Harlequin Bugs

The best preventive measure is perhaps keeping the garden or plantation clean. Be sure to throw debris and decaying vegetation, which can make attractive locations for overwintering. Pulling weeds will also help as it is one of the most common breeding sites. If there are no weeds in the garden, it will be less likely that the pest will survive. The same thing is true in the case of wild mustard plants. Lastly, growing strong plants will help a lot. Keep them healthy, and in the end, they will be more resistant to damages.


  1. George K Taylor February 15, 2020
  2. Peter Davey April 9, 2020

Leave a Reply