Harlequin Bugs

Hemiptera: Pentatomidae (Murgantia histrionica)


Adult harlequin bugs are about 5 to 10 mm in length and have a black shield-shaped body with red, yellow, or orange markings. Harlequin bugs are in the stink bug family and produce foul smells as a defense mechanism against predators. Adults and nymphs are common pests of many vegetables.

Life Cycle

Harlequin bugs have three life stages: egg, nymph, and adult. In early spring, the overwintering adults emerge from leaf litter and debris and start to mate. The females lay about 12 barrel-shaped eggs with black and white stripes in a cluster underside of the leaves of their host plants such as cabbage, broccoli, kale, turnip, and radish. Depending on the temperature, the eggs hatch into nymphs from 4 to 29 days. A newly hatched nymph cannot fly but it develops its wings over time. Nymphs feed for four to nine weeks on the stems and leaves of plants and turn into adults. The whole life cycle takes 50 to 80 days and can have up to three generations per year under favorable conditions.


The harlequin bugs feed on over 50 species of plants but have a strong preference for the family of Brassica, which includes cabbage, broccoli, cauliflower, and mustard. They are also the secondary pest of various fruits and vegetable crops such as beans, cantaloupe, onion, and tomato. Both nymphs and adults feed on plant tissue using their piercing and sucking mouthparts. This can cause yellow or white blotches at the feeding site following wilting or deforming. Heavy infestation may result in plants turning brown and dying.


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