Hibiscus Harlequin Bug: Essential Facts & Tips

The hibiscus harlequin bug is a vibrant and striking insect that often catches the attention of gardeners and insect enthusiasts alike. While these bugs can undoubtedly add a pop of color to your garden, it’s vital to know the possible effects they may have on plants in their vicinity.

Belonging to the species Murgantia histrionica, these pests are known for wreaking havoc on a variety of vegetables, especially those in the Brassicae family, like cabbage, mustard, and radish. Unfortunately, the damage done by these insects isn’t merely cosmetic, as their sap-sucking habits can severely weaken and possibly kill the affected plants. It’s essential to understand their life cycle, preferred habitats, and effective ways to control their populations.

Among the issues to consider are:

  • Life stages: eggs, nymphs, and adults
  • Potential attractants in the garden, such as cleome flowers
  • Understanding their impact on common vegetable crops
  • Options for natural control methods, like eliminating groundcovers or weedy areas

Hibiscus Harlequin Bug Overview

Identification

The hibiscus harlequin bug, also known as Tectocoris diophthalmus, is a brightly colored insect with a metallic sheen. It’s found in Australia, New Guinea, and the Pacific Islands. Some distinguishing features include:

  • Vivid red, orange, or yellow markings
  • Shield-shaped or oval body
  • 1/4 to 3/8 inch long

Examples of the hibiscus harlequin bug can be seen here.

Cotton Harlequin Bug

The cotton harlequin bug is another name for the hibiscus harlequin bug. Both names refer to the same species.

Tectocoris Diophthalmus

Tectocoris diophthalmus is the scientific name of the hibiscus harlequin bug. It’s native to eastern Australia and is known for its vibrant colors and distinct markings.

In comparison, other bugs in the same region may not share the same features. Here’s a table to highlight the differences:

Bug Name Coloration Shape Size
Hibiscus Harlequin Bug Bright, metallic Shield-shaped 1/4 to 3/8 in
Other Generic Bug Dull, non-metallic Varies Varies

The hibiscus harlequin bug prefers to feed on plants such as hibiscus and cotton, but may also attack other plants. The unique appearance of the bug makes it stand out among other critters in Australia.

Life Cycle and Behavior

Eggs and Nymphs

The life cycle of the harlequin bug starts with eggs laid by the females. These eggs are tiny, white, and resemble little kegs standing on end in a double row1. Once hatched, the nymphs consume plant material and grow through a series of stages before transforming into adults1. Here are a few characteristics of eggs and nymphs:

  • The eggs are laid in clusters on host plants
  • Nymphs go through several growth stages called instars
  • Both nymphs and adults feed on plant sap

Adults

Adult harlequin bugs, also known as stink bugs, are the final stage of their life cycle1. These insects overwinter in the adult stage1. Here are the main features of adult harlequin bugs:

  • They feed on a variety of vegetables, preferring plants in the Brassicae family2
  • Adult bugs can cause significant damage to crops by sucking the fluids from plant tissues3

Comparison of Harlequin Bug Stages

Life Stage Appearance Feeding Behavior
Egg Tiny white kegs on host plants1 None
Nymph Smaller, less colorful versions of the adult1 Feed on plant sap1
Adult Colorful, triangular-shaped thorax4 Feed on plant sap1

In conclusion, understanding the life cycle and behavior of the harlequin bug can help in planning effective pest management strategies.

Feeding and Damage

Host Plants

Harlequin bugs, a pest of many vegetables, primarily attack plants in the Brassicae family, such as mustard, cabbage, greens, and radish. They can also be a secondary pest to various fruit and vegetable crops like beans, cantaloupe, onion, raspberry, pear, and tomato1. While not their primary target, they have been known to feed on plants from the family Malvaceae, which includes hibiscus2.

Feeding Habits

These insects have a preference for feeding on the sap of their host plants2. As true bugs, they use their piercing-sucking mouthparts to extract the sap, which can cause significant damage to the plant.

Main feeding characteristics on plants:

  • Preference for Brassicae family plants1
  • Feeding on sap2
  • Piercing-sucking mouthparts

Symptoms of Damage

The damage caused by harlequin bugs is seen in various ways, depending on the affected plant. Common symptoms include small white spots on leaves, which occur as a result of the bugs sucking the sap2. Another sign could be the buds dropping off early due to insect feeding4.

Symptoms of harlequin bug damage:

  • Small white spots on leaves2
  • Early bud drop4
Family Preferred host plants Symptoms of damage
Brassicae1 Cabbage, mustard Small white spots on leaves2
Malvaceae2 Hibiscus Early bud drop4

Control and Prevention

Natural Predators

  • Beetles: Some beetles prey on harlequin bugs and help control their population1.
  • Wasps: Parasitic wasps are another effective natural predator2.

These predators can be attracted by planting flowers that support their habitat.

Insecticidal Soap and Other Treatments

Insecticidal soap is a popular treatment for hibiscus harlequin bugs:

  • Pros: It’s eco-friendly, affordable, and easy to apply4.
  • Cons: Needs repeated applications and may harm some beneficial insects3.

Spraying the bugs directly with soapy water is another option.

Treatment Pros Cons
Insecticidal Soap Eco-friendly, affordable Repeated applications, harms some good insects
Soapy Water Easy to make and apply Less effective, requires more frequent use

Cultural Practices

Implementing these practices can minimize harlequin bug damage:

  1. Watering: Ensure proper watering to keep the hibiscus healthy and less vulnerable to pests.
  2. Debris: Remove plant debris, as they provide hiding spots for bugs5.
  3. Wild Mustards: Control wild mustard plants, which serve as alternative hosts for harlequin bugs6.

Remember, keeping your hibiscus plants healthy and observing good garden hygiene can help prevent harlequin bug infestations.

Other Susceptible Plants

Vegetable Garden

Harlequin bugs are known to heavily damage various plants in vegetable gardens, particularly those in the Brassicaceae family. Some of the most commonly affected plants are:

  • Broccoli
  • Cabbage
  • Brussels sprouts
  • Cauliflower
  • Kale
  • Radish
  • Mustard greens
  • Turnips

These bugs can also damage several fruit and vegetable crops, affecting plants like tomatoes, asparagus, and okra. The insects damage these plants by sucking the fluids from plant tissue, causing discolored leaves and weakened plants.

Ornamental Plants

Harlequin bugs can also infest ornamental plants. Some noteworthy examples are:

  • Bottlebrush
  • Roses
  • Hibiscus plant
  • Cultivated cotton
  • Some trees
Affected Plants Damage Caused
Vegetable Garden (cabbage, kale) Discolored leaves, weakened plants
Ornamental Plants (roses, cotton) Discoloration, stunted growth

In summary, harlequin bugs have a wide range of host plants in vegetable gardens and among ornamental plants. Vigilance and proper control methods are crucial to protect your plants from these damaging pests.

Harlequin Bugs in Different Regions

Subtropical and Tropical Regions

The Harlequin Bug, scientifically known as Murgantia histrionica, is a pest commonly found in subtropical and tropical regions. It prefers to reside and feed on plants in the family Brassicae, such as:

  • Mustard
  • Cabbage
  • Greens
  • Radish

These bugs can also be a secondary pest on various fruit and vegetable crops like beans, cantaloupe, onion, raspberry, and tomato.

Other Stink Bugs

Harlequin bugs belong to the order Hemiptera and are a part of the Heteroptera sub-order. They share similarities with other types of Stink Bugs, such as:

  • Being members of the Scutelleridae family
  • Having a unique triangular-shaped thorax
  • Sucking leaf sap

However, Harlequin bugs are distinct due to their vivid red, orange, or yellow markings on a black body.

Comparison between Harlequin Bugs and typical Stink Bugs:

Feature Harlequin Bug Typical Stink Bug
Classification Hemiptera, Heteroptera, Scutelleridae Hemiptera, Heteroptera, Pentatomidae
Color Black with red, orange, or yellow markings Brown, green, or dull-colored
Preferred habitat Crucifers and other fruit, vegetable crops Various vegetables, fruit trees, and soybean

Harlequin bugs are prevalently found in subtropical regions and have been reported in countries such as Mexico. While they share some similarities with other Stink Bugs, their unique appearance and preferred host plants distinguish them from the rest of the Hemiptera family.

Footnotes

  1. https://entnemdept.ufl.edu/creatures/veg/leaf/harlequin_bug.HTM 2 3 4 5 6 7 8 9 10 11 12

  2. https://extensionentomology.tamu.edu/insects/harlequin-bug/ 2 3 4 5 6 7 8 9

  3. https://extension.wvu.edu/lawn-gardening-pests/pests/harlequin-bug 2

  4. https://extension.umd.edu/resource/harlequin-bug-vegetables 2 3 4 5

  5. https://extension.wvu.edu/lawn-gardening-pests/pests/harlequin-bug

  6. https://extensionentomology.tamu.edu/insects/harlequin-bug/

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Hibiscus Harlequin Bug

 

what is this bug?
Hi,
We found this colourful bug on our Hibiscus plant a while ago. A few weeks after seeing the one there were a whole group of them (but mainly blue rather than orange). They are quite impressive, it would be good to know what they are.
Thanks,
Andrew

Hi Andrew,
It is a great big world out there and what lives in your backyard does not live in our backyard. Identification is often very difficult when you know where you are looking. We hope you live in Australia. This is a Cotton Harlequin Bug, Tectocoris diophthalmus, also called the Hibiscus Harlequin Bug. Nymphs are more blue and adults more orange.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com 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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