Harlequin Bugs

by Wizzie Brown

Harlequin bugs are a type of stink bug and have an incomplete life cycle with three life stages — egg, nymph, and adult. Eggs are keg-shaped, typically laid in two rows on host plants, and are black and white-striped. Nymphs range in color, starting out orange, changing to brown and orange, and moving to black and orange/red in the adult stage.

Harlequin bugs have piercing-sucking mouthparts that they use to feed on plant juices. They prefer plants in the cabbage family and can often be found on collards, cauliflower, Brussel sprouts, radish, turnips, mustard and cabbage. If these plants are not available, then they can move onto other plants in the garden. Damage appears as yellowing, wilting, browning, and sometimes death of the plant.

Harlequin bugs overwinter in the adult stage. Adults merge in spring when weather becomes warm to locate host plants for feeding. Usually in Central Texas, people discover Harlequin bugs on their winter crops that are beginning to decline in early spring. It is important to kill these Harlequin bugs as they can move into new crops planted in the garden.

Adult harlequin bugs can be managed by vacuuming or hand-picking them from plants. Dump captured bugs into a bucket of soapy water to kill. If you choose to hand-pick, wear gloves as they can bite and release an unpleasant smell. If you discover eggs, you can squish them or remove the infested leaf from the plant and throw it in the trash. For management of nymphs, you can hand-pick, vacuum, or use a pesticide with active ingredients such as insecticidal soap, pyrethrins, azadirachtin (a.k.a. neem), or horticultural oil. Make sure to read and follow all label instructions and ensure that the product you choose can be used on food crops.

For more information or help with identification, contact Wizzie Brown, Texas A&M AgriLife Extension Service Program Specialist at 512.854.9600. Check out my blog at www.urban-ipm.blogspot.com

This work is supported by Crops Protection and Pest Management Competitive Grants Program [grant no. 2017-70006-27188 /project accession no. 1013905] from the USDA National Institute of Food and Agriculture