Harlequin bugs are no laughing matter

These harlequin bugs are on an Asian pear at the Fremont Community Garden in midtown Sacramento. These are mostly nymphs, An adult is next to the stem. (Photo: Debbie Arrington)

This stink bug cousin loves mustard, cabbage, kale and fruit 

By Debbie Arrington

These harlequins aren’t funny. In fact, they’re real stinkers.

This month, they’ve invaded Sacramento gardens with a vengeance. They’re looking for cozy spots to spend the winter. In the meantime, they’ll chow down.

With their distinctive and colorful markings, harlequin bugs are easy (and alarming) to spot. The young ones tend to hang out in clusters or large groups.

It’s those spots that give harlequins their nickname. A member of the stink bug family, Murgantia histrionica are shiny black with orange, yellow or red markings. Adults are about 3/8 inch long.

The nymphs, or immature bugs, are particularly colorful. They look almost like mutated lady bugs, but in reverse, with red or orange dots on a black background. The nymphs go through several stages, molting four or five times before reaching their adult size and coloring. While young, they can’t fly.

Meanwhile, they eat. Like other stink bugs, they plunge their feeding tubes into fruit or vegetables, and suck out the juices. Besides deforming the fruit, the enzymes they leave behind makes it inedible. They also feed on leafy greens, causing white blotches where they ate. Heavy infestations will kill plants.

This time of year, they’re hunting for nesting areas. Harlequins love cabbages, mustard and kale. They prefer to lay their eggs on cole crops such as those members of the cabbage family. If they can find an old cabbage or mustard plant to hang out in all winter, they’re in harlequin heaven.

Also like other stink bugs, harlequins seem immune to most pesticides. The best control is hand-picking the nymphs off plants and squishing them (with gloves – they do stink). Or knock them into a bucket with soapy water; they can’t swim.

UC Cooperative Extension master gardeners also recommend destroying old cabbages, mustards and other potential host plants so the harlequins don’t have a place to hang out. Also clean up weedy spots near fruit trees or garden areas. Those weeds may shelter harlequins.

For more information: http://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/harlequinbug.html