The harlequin bug, Murgantia histrionica, is a red (sometimes yellow or orange) and black-spotted species of stink bug. It is an important pest of crops in the mustard family in the southern United States, but can also affect other crop plants. Harlequin bugs are native to North America and there can be multiple generations a year. 

Symptoms and Diagnosis 

Commonly found on plants in the Brassica family (mustards, cabbage, and kale), cleome, and even tomatoes, okra, squash, corn, beans, and asparagus. Harlequin bugs pierce the plant material with a piercing-sucking mouthpart and will suck the plant sap out, causing stippling and discoloration on the foliage/fruit. Young plants can wilt, turn brown, and die if the infestation is serious enough. Older plants can become stunted.  

Life Cycle 

Harlequin bugs overwinters as an adult in protected areas such as under dead weeds, leaf litter, or the bark of trees. They then emerge in spring; 2 weeks after emergence the females lay barrel-shaped, black and white eggs on the underside of leaves. Eggs hatch in about 20 days and then the nymphs will feed for 6-8 weeks until they become adults. Females can lay up to 155 eggs each.  

Integrated Pest Management Strategies 

1. Sanitation. Control weeds in susceptible crops and in areas adjacent to gardens to decrease breeding and overwintering habitat. It is important to remove weeds early in the growing season before stink bug populations increase or the loss of habitat may force pests to move into the garden. 

2. Collect insects. Hand pick and destroy eggs and bugs. 

3. Use natural controls. Encourage other natural predators such as parasitic wasps and flies by growing small-flowered plants. The unpleasant odor produced by stink bugs deters many predators but several bird species do consume these pests. 

4. Use trap crops. Plant trap crops of mustard and treat that area with an appropriate pesticide. 

5. Use insecticides. If damage is severe, use insecticidal soap, sabadilla, pyrethrin or permethrin (Eight). 

Organic Strategies 

Strategies 1, 2, 3, and 4 are strictly organic approaches. For an organic approach to Strategy 5, consult the Organic Materials Review Institute (OMRI™) for appropriate insecticidal soap and pyrethrin products. 

Pesticide Disclaimer: 

Always follow the product's label and ensure the product is effective against harlequin bugs. Not following the pesticide label before usage is a violation of federal law.