Released: September 30, 2002

Racing-Striped Bugs Just Seeking Shelter

MANHATTAN, Kan. – Through most of the year, Kansans hardly notice box elder bugs – even though the nymphs are bright red and the adults are brown-black with red racing stripes.

When the weather cools off, however, box elder bugs can start congregating by the thousands on the sunny sides of homes and other buildings.

"That can be a little worrisome. But these bugs also can become household pests as they crowd into cracks and crevices, looking for shelter. Some may make their way into wall voids, where they’ll hibernate through winter. Others may explore further and end up flying around rooms, accumulating in light fixtures, and leaving fecal matter on curtains and drapes," said Leroy Brooks, entomologist with Kansas State University Research and Extension.

The bugs can emerge as an indoor nuisance during wintertime warm spells, too.

But, box elder bugs don’t bite, Brooks said. They don’t harm buildings, furniture, clothes or food – unless you smash them, in which case they’ll leave a stain and bad smell.

In some cases, they also can be fairly easy to control without chemicals.

"You may be able to cut down a nearby female box elder tree – the bugs’ usual host. The female trees produce the seed pods the bugs use for food," Brooks said. "Golden rain trees are the host of the box elder bug’s pesky and very similar-acting first cousin, the red-shouldered bug.

"Results from this approach aren’t guaranteed, though, because these bugs can fly. So your neighbors’ trees could also be a source of infestation."

Other deterrents: Remove stacked lumber, firewood and other yard clutter that could offer winter shelter. Caulk, putty or weatherstrip potential entry points to the house. Vacuum up bugs that make it into living spaces and then seal and dispose of the bag.

"If bugs are congregating outdoors in an accessible location, you can eliminate them by pouring boiling water on them, while it’s still at least 165 to 185 degrees. That’s not easy, of course, and it might be dangerous to try," Brooks said. "Or, you can spray the bugs with a solution of about one-half cup laundry detergent in a gallon of water, repeating whenever more bugs take the first congregation’s place."

Products labeled for outdoor nuisance insects can help if these non-chemical options fail.

"We’re seeing both safer and more effective products being marketed today, as compared to just a few years ago. But you’ll probably have to do some searching to find them," the entomologist said. "Look for products listing cyfluthrin, permethrin or cypermethrin as an active ingredient. Check to see if the label has the box elder bug listed. Red-shouldered bug probably won’t be included separately."

For treating small areas, such as a front porch or door steps, a one- or two-quart spray bottle of read-to-use insecticide is likely to be the faster, safer and more convenient choice, Brooks said. For treating larger areas, a product concentrate (to be mixed with water), applied with a pump-up or hose-end sprayer, will be the more practical option.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Kathleen Ward, Communications Specialist
kward@oznet.ksu.edu
K-State Research& Extension News