How to Control Harlequin Bugs: 5 Essential Strategies for Gardeners

Harlequin bugs are major pests of cruciferous and even other crop plants. Here’s how to control harlequin bugs and stop them from destroying your plants.

Harlequin bugs are common garden pets that prefer to feed on cruciferous plants such as vegetables in the Brassica family.

This includes cabbage, broccoli, mustards, and radish, to name a few.

These tiny bugs can be identified with their orange/ red and black patterned bodies. They can quickly wreak havoc if they find their way to your garden.

In this article, I will mention how you can control harlequin bugs and protect your precious greens.

How To Control Harlequin Bugs

Control Techniques

The Murgantia histrionica, i.e., harlequin bugs, are insect pests widespread in the southern and central parts of the United States.

They are also identified as broccoli or cabbage bugs, named after their host plants.

Harlequin bug eggs are laid in large batches and can quickly multiply their populations.

The adult harlequin bug population finds shelter among organic mush, such as plant debris and the underside of leaves.

However, worry not. There are some control techniques that you can use to manage these potential pest attacks.

You can opt for generic techniques, chemical treatments, or physical solutions. You can also choose to use other plants or animals to help.

Let’s take a look at these ways in detail.

Generic Techniques

The best way to keep pests away from your crop is to make your crop strong enough to be susceptible to pest attack.

You can do this by being careful with your plant’s soil and water needs.

Watering deeply to promote strong roots, running soil tests on potential new planting sites, and giving your plant the required nutrition will ensure it grows strong.

Immature Harlequin Stink Bugs

For instance, the plants of the Brassica family thrive on heavy calcium.

To keep the harlequin bugs away, make plenty of calcium available to your plant through eggshells, oyster shells and solutions, and other calcium supplements.

Maintain your plants by weeding them out regularly and checking for bugs or pests if you spot a handful of harlequin bugs, hand pick and toss them into garbage bins.

Chemical Treatments

The second major technique you can use to weed out your pests is chemical treatment.

Pyrethrin is an effective chemical to treat a harlequin bug infestation.

The chemical is derived from the seeds of the plant Chrysanthemum cinerariifolium.

This white daisy-like plant attacks the insects’ nervous system to incapacitate them.

You can use pyrethrin in an insecticidal soap solution with neem.

Sprinkling this solution directly on the eggs, nymphs, and even harlequin bugs in the adult stage early in the morning will ensure maximum results.

Mating Harlequin Stink Bugs

You can also make an organic pyrethrin pesticide at home. Dry and grind the flower heads of the fully bloomed Chrysanthemum cinerariifolium.

Add the powder to warm water and leave it for three hours. Follow by adding some dish soap and using the soapy water solution on the nymphs immediately.

You can repeat this process weekly on the newly hatching nymphs for the best results.

Polycultures & companion plants

Another effective technique to keep harlequin bugs away is to use companion plants for your main plant and intercropping.

Create a boundary of strong-odored plants like mint, rosemary, garlic, chamomile, or even chrysanthemum.

These plants will overpower the smell of your brassica plants and protect them.

Or you can grow them in a mix with your main plant to confuse and divert the harlequin bugs.

You can also use trap crops.

In this method, you attract and trap the pests by growing an initial batch of plants or crops and then discarding them. You can then plant your main batch.

Harlequin Beetle

Physical Solutions

Some individuals have also seen success using physical barriers such as row covers.

These work best for plants that don’t require pollination, such as cabbage.

You can also use white silicate clay spray on your plants to deter pests.


Beneficial insects like hymenopteran wasps and guinea fowls are great helpers in attacking harlequin bugs and other pests.

If you’re concerned about parasitic wasps, they are tiny and do not sting, which makes them perfect garden dwellers.

On the other hand, unlike chickens, the guinea fowl do not destroy plants and vegetation, making them an ideal flock to have.

Frequently Asked Questions

Are harlequin bugs harmful to garden?

Harlequin bugs can be very harmful to garden flowers, vegetables, and fruits.
They suck the sap from plants, and their feeding damage sometimes goes unnoticed until plants are weakened or stunted.
Insecticides can be effective in controlling problem harlequin bug populations, but a better approach is to remove weeds.
These are a major food source for harlequin bugs and provide barriers such as mulching and dusting these areas with diatomaceous earth, which acts as a natural barrier between the harlequin bugs and their food sources.

Are harlequin bugs harmful to humans?

Harlequin bugs are not considered to be harmful to humans, as they feed mostly on plants, fruits, and vegetables.
However, these bugs can become a nuisance when they gather in large clusters. Large swarms of these bugs may cause allergies or skin irritation if touched.
In addition, the presence of the bug can contaminate the product that is being harvested from gardens or farms.
While harlequin bugs are not directly hazardous to human health, their presence could cause problems for farmers and gardeners who need to make sure that their crops are pest-free before the sale.

What is the lifespan of a harlequin bug?

The lifespan of a harlequin bug is roughly two years, with larvae emerging in the spring and first adults seen in late summer.
It typically overwinters as an egg on grasses, roses, or other low vegetation. The female adults lay their eggs in masses that are yellow or white when first laid but turn brownish-black as they mature.
The developing nymphs will molt five times before becoming adults. They feed on various plants, including crucifers such as radishes, cabbage, and mustard.

What eats the harlequin bug?

The harlequin bug is eaten by a variety of predators, including spiders, ants, frogs, birds, and beetles.
They will also be eaten by beneficial predator insects such as ladybugs and hoverflies.
In order to more effectively protect itself from these predators, the harlequin bug has evolved the ability to produce chemical defenses that are rather foul-smelling.
Many times a predator will pick up the scent of this defensive secretion before they ever get close enough to consume the harlequin bug.

Wrap Up

Harlequin bugs are common garden pests in Central America that usually feed on cruciferous plants such as wild mustard, cabbage, broccoli, etc.

They can often destroy the entire crop or garden if not controlled and managed.

Several ways, from generic management techniques to chemical treatments and even using companion plants and animals, can be employed to destroy these notorious pests.

Thank you for reading!


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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