NC State Extension Publications

Description and Biology

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Harlequin bugs, Murgantia histrionica, are robust and black with vivid red, orange, or yellow markings. They are shield-shaped or oval in top view and 1/4 to 3/8 inch long. Females lay tiny, barrel-shaped eggs that are pale with two black bands. The top has a black circle or crescent shaped, and a tiny black spot occurs between the side bands. Eggs are laid in double-row clusters of 10 to 13 on the leaves of plants in the mustard family. Tiny nymphs are oval with bold marking. Older nymphs resemble adults but lack wings. Harlequin bugs overwinter as adults by hibernating among plant debris. Adults emerge early in spring and after 2 weeks, females begin depositing eggs on the undersides of leaves. Each female may deposit up to 155 eggs or so. In early spring, eggs hatch in about 20 days. Eggs hatch in 4 to 5 days as the weather becomes warmer. Nymphs feed for 6 to 8 weeks and develop through 5 stages before becoming adults. Two to four generations occur each year in North Carolina.

Photo of a harlequin bug on a leaf

Some harlequin bugs have vivid black and red markings.

Photo of a yellow harlequin bug

The markings on harlequin bugs vary from red to yellow.

Photo of harlequin bug eggs on underside of leaf

Female harlequin bugs usually lay eggs on the undersides of host plant leaves.

Photo of harlequin bug nymphs

Harlequin bug nymphs usually cluster around their egg shells when they first hatch.

Host Plants

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Harlequin bugs feed on cleome, flowering cabbage, ornamental kale, and stock (they can also be a problem in vegetable gardens). Harlequin bugs attack nearly all crucifers, including common weeds of the mustard family such as wild mustard, shepherdspurse, peppergrass, bittercress, and watercress. If infestations are heavy, harlequin bugs also feed on squash, corn, bean, asparagus, okra, and tomato. Adults and nymphs pierce stalks, leaves, and veins with their needle-like mouthparts and extract plant juices. Stems and leaves injured in this manner develop irregular cloudy spots around the puncture wound. Young plants are likely to wilt, turn brown, and may eventually die whereas older plants are only stunted.

Photo of harlequin bug feeding on plant

Harlequin bugs feed on unusual host plants when plants in the mustard family are scarce.

Residential Recommendations

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Harlequin bugs can be removed by hand and dropped into a container of soapy water to kill them. Should the amateur horticulturist be too squeamish to handle these bugs, insecticides labeled for residential use should give adequate control if applied according to the directions presented on the label of whichever pesticide is used. Don't apply pesticides to plants in flower to avoid killing pollinators.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension center.

This factsheet has not been peer reviewed.


Professor Emeritus
Entomology & Plant Pathology

Find more information at the following NC State Extension websites:

Publication date: March 21, 2020
Revised: March 21, 2020

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