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MSU entomologist offers tips on controlling a growing stink bug infestation in Michigan

brown marmorated stink bug

Last year was one of the worst years for the invasive pest known as the stink bug, and this year is going to be even worse, according to Michigan State University Entomologist Howard Russell, aka MSU’s Bugman.

“The one people are complaining about now is the brown marmorated stink bug, says Russell. “It showed up in Michigan for the first time around 2010. It was first found in southwest Michigan and ever since has been spreading throughout the Lower Peninsula.”

Stink bugs are a major nuisance because they seek shelter inside houses in the fall. These pests will not cause structural damage or reproduce in homes. They do not bite people or pets. Although they are not known to transmit disease or cause physical harm, the insect produces a pungent, malodorous chemical and when handling the bug the odor is transferred readily.

“They are a pretty important plant pest that attack tree fruit like apples and peaches, and they’ll attack a lot of garden crops, too, like tomatoes, and even some field crops like corn and soybeans.

“We’ve yet to see a lot of damage in the fields as a result of this bug. They’re most notorious right now because they invade homes and look for a place to stay for the winter.

“Unfortunately we’re just starting that process. Four of five years ago I had complaints from people finding two or three in their homes during the winter. A couple years ago it was maybe a dozen or so. Now I’m getting calls from people who see dozens in their home, and that trend is going to continue to go up. Out east where the bug has been around for a while, they shovel them off their front porches. So people can expect to see hundreds if not thousands on the outsides of their homes in the next few years.”

While there are products available at hardware and big box stores homeowners can spray on their homes in the fall of the year to kill the bugs when they see them congregating on the outside of the home, Russell says the best long-term method to control them is to prevent their entry. Caulk or seal cracks and crevices on the exterior. No amount of caulk will keep the beetles out of homes with vinyl siding because vinyl siding and soffits permit gaps in the vinyl panels. Also caulk around outlet and switch boxes, ceiling fixtures, heat ducts and other openings in interior walls; that may at least keep the bug in the walls and out of the living space.

Spraying the outside walls, especially the south and west facing ones, in September and October also can help reduce bugs. Do-it-yourselfers can use bifenthrin (sold as Ortho Max Home Defense). Before treating the whole house, spray a small test area to make sure the insecticide does not stain the siding or paint. Be sure to wear protective clothing, such as a wide-brimmed hat and raincoat, and goggles. 

“Once they get in, though, it’s a little more difficult. You can sweep or vacuum them up, but you may want to use an old junker vacuum because the bugs may live up to their name and stink up your vacuum.

“Some people out east have found that light traps work pretty well, and the ones you can make are as effective as the fancy ones that you can buy. And a light trap is simply an aluminum foil roasting pan that you can buy at the grocery store. You fill it with a couple inches of soapy water and shine a desk lamp in it. The bugs are attracted to the light and will crawl in the water and drown.”

Layne Cameron contributed to this report.

MSU Today airs Sunday afternoons at 4:00 on 105.1 FM and AM 870.

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