Harlequin Bugs

Harlequin bugs are black and red stinkbugs that feed on members of the cabbage family.

Harlequin bug description

The telltale shield-shaped back of the stinkbug family (Pentatomidae) make it easy to identify this garden pest. Also known as calico bugs, harlequin cabbage bugs, and fire bugs, harlequin bugs (Murgantia histrionica) are shiny black with yellow, orange, and red markings. They are often confused with Bagrada bugs, but harlequin bugs are significantly larger, and they lack the white markings of Bagrada bugs. Adults can reach 3/8 of an inch in length. If you allow yourself to get past the bit about how these are pests, they really are strikingly beautiful. That being said I still feed them to my chickens whenever I see them.

Adult harlequin bug on the left and nymph on the right (Linda Tanner) CC BY 2.0

Harlequin bug lifecycle

These pests tend to lay their black-and-white striped eggs in November in warmer regions. This is probably because that is when their favorite foods are being planted! Clusters of 12 barrel-shaped eggs are laid on leaves. Allowed to hatch, they will spread out as they go through four or five molts before reaching adult size, usually around March or April. Harlequin bug adults often hide in weedy areas, or near blackberries.

Damage caused by harlequin bugs

Brussels sprouts, cauliflower, radishes, cabbages, horseradish, turnips, kale, and other cole crops are the harlequin bug’s favorite hosts. These sap-sucking pests chew on stems and leaves, leaving a trail of white or yellow blotches. Since they tend to use pheromones to congregate and attract mates, feeding damage can be extensive. Heavy infestations can cause plants to wilt, brown, and die.

​Harlequin bug controls

Hand-picking in early spring is the best organic control for these pests. You can drop adults in a bucket of soapy water. You can step on them but, keep in mind, they are stinkbugs and they do smell bad when threatened. Also, since many members of the stinkbug family eat mustard, you don’t want to smack one that happens to be crawling up your arm or leg. Chemicals, called glucosinolates, are used by members of the mustard family for self-defense. Harlequin bugs use those chemicals for their own defense and it can burn your skin. My hens get any I find, without any problem.
​
In the fall, inspect plants for eggs and simply brush them off of host plant leaves. When they hatch, they will starve. You can reduce or eliminate hiding places by clearing out weedy areas and composting or destroying old cole and mustard crops. Insecticides are generally ineffective against stinkbugs. Parasitic wasps are believed to attack harlequin bug eggs, so avoid broad spectrum insecticides.

​Keep a lookout for these beautiful pests and their striking eggs. Enjoy them, and then end them.