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Be on the watch for brown marmorated stink bugs

Winter is a time when you assume you get a respite from the insects of summer. While that is true most of the time, you may still cross paths with a few insects. A variety of insects use buildings to hide in when it gets cold and can be seen walking around your home even in the dead of winter. One of these opportunistic insects is the brown marmorated stink bug (BMSB).

Brown marmorated stink bug.
Photo: Jeff Hahn, U of MN Extension
Sometimes confused as a beetle, BMSB is ½ inch long and a mottled brown and gray color (marmorated means marbled). They are stout, shaped like a shield or a badge.  There is a large triangular plate, known as scutellum, on their back. If you flip a stink bug over, you can see its needle-like mouthparts. Ask an expert if you suspect you have found a BMSB.

If you are thinking you have not seen BMSB before, that’s probably true. This invasive insect is relatively new in Minnesota; it was first discovered here in 2010. Originally from Asia. BMSB was found in the U.S. for the first time in Pennsylvania in the 1990’s. Currently, this insect has been confirmed in 22 counties in Minnesota, including the Twin Cities.

During the summer, BMSB feeds on many kinds of different plants; it is known to feed on over 300 species. But as it gets colder in the fall, BMSB look for places to spend the winter and, just like boxelder bugs and multicolored Asian lady beetles, this commonly brings them to buildings.

They will generally remain in cracks, crevices, voids, and other sheltered sites around the home as long as it stays cold. However, mild weather can cause them to wake up and move into the interior of a home. Fortunately, people typically see just a few stink bugs at a time; just physically remove them as you find them. They do not damage any property and are just a nuisance inside homes.

However, the brown marmorated stink bug can cause severe damage to crops and other plants. While this insect is usually easy to dispose of inside your home, it is destined to become a severe plant pest in Minnesota.

An important step in the battle against BMSB is knowing where they are in the state. If you find a confirmed BMSB, check their known distribution in the state on this map. If you find this insect has not been reported in your neighborhood before, consider informing the Minnesota Dept. of Agriculture. They use reports from residents to help map their presence.

For more information, see University of Minnesota Extension’s Brown marmorated stink bug.

Author: Jeffrey Hahn, Extension Entomologist

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