Pest of the Week - Harlequin Bug

The harlequin bug Murgantia histrionica (Hahn) is also know by other common names such as "Calico Back", "Calico Bug", "Fire Bug".  The harlequin bug injures the host plants by sucking the sap of the plants, causing the plants to wilt, brown and die. Like other stink bugs, they produce odors from their thoracic glands, using them as a defense against predators.  Plants commonly attacked by the harlequin bug include such crucifers as cabbage, cauliflower, collards, mustard, Brussels sprouts, turnip, kohlrabi and radish.

Harlequin bug - Colorado State University

Eggs of the harlequin bug, Murgantia histrionica (Hahn). Photograph by James Castner, University of Florida.

Natural History

Harlequin bug life cycle - UC Davis

Eggs of the harlequin bug resemble tiny white kegs standing on end in a double row. Approximately 12 are laid together, usually on the underside of the leaves of the host plant. Each egg is marked by two broad black "hoops" and a black spot. The eggs hatch in from four to 29 days, the time varying with the temperature.

There are five or six nymphal stages that feed and grow for four to nine weeks before they are capable of mating and laying eggs.  The head coloration of the nymphs ranges from pale orange, darker orange to black in the final nymphal form.

Adult bugs are 3/8-inch long and mottled red, black, and yellow or orange.

Management Strategies

Hand-picking and destruction of the insect pests and egg masses may deter damage where low numbers of insects are found. Hand destruction of the adults in the fall and spring as they emerge from "hibernation" before they lay eggs is an effective control. This may be aided by the use of trap crops of turnip, kale, or mustard in the very early spring or late in the fall after the main crop has been harvested. Once the pests have concentrated in these areas, they can be killed by applying insecticides or by covering the trap crop with straw and burning. Trap crops should never be used unless they can be given careful attention to destroy the bugs attracted to them.   Insecticides are generally not recommended in gardens for stink bugs.

Additional Information

Hemiptera - True Bugs - Colorado State University

True Bug Lifecycle - UC Davis

Harlequin bugs 2013 a growing problem in Pennsylvania? - Penn State University

Harlequin bug - Rutgers University