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University of Minnesota Extension

Watch for brown marmorated stink bugs

Brown shield-shaped insect on a leaf.

Brown marmorated stink bug (BMSB) is an invasive insect, first found in Minnesota in St. Paul in 2010. It has since been discovered in 23 additional counties. This insect is easily moved, especially in boxes and vehicles, and can eventually spread to all parts of Minnesota.

This species feeds on more than 170 different plants, both ornamentals and agricultural crops, including apples, soybeans, cherries, crab apples, sunflowers, eggplant and tomatoes.

Their feeding can cause severe damage.  Minnesota is just starting to see economic injury to crops, including apples.

BMSBs are also a problem because they get inside homes and other buildings as they seek shelter for the winter.  They can do this in large numbers, similar to boxelder bugs, and be a nuisance indoors.  While they are not welcome in our homes, finding them there can help fight BMSB in our state.

A big part of the battle with BMSB is knowing where they are located; it is not always obvious when they first arrive in an area. Because early detection is critical when fighting BMSB, the sooner they are recognized, the sooner action can be taken against them.

How to identify brown marmorated stink bug

Brown marmorated stink bug lying on its back with magnified circle showing small, iridescent pits.
Underside of brown marmorated stink bug

Stink bugs can be confused with other insects.  To make sure you have a stink bug, look for the following:

  • A robust body, generally shaped like a shield or a badge.
  • A large triangular plate (called a scutellum) on its back.

A brown marmorated stink bug has the following characteristics:

  • ½ inch long.
  • A mottled brown color.
  • White banding on the antennae.
  • Black and white banding along the side of the abdomen.
  • Black, thick veins in the wings at the tip of the body.
  • On the underside, iridescent pits along the edge of the body and on the legs.
Brown and tan, shield-shaped insect with long antennae.
Western conifer seed bug

While there are native stink bugs that can be confused with brown marmorated stink bugs, native stink bugs are not found in buildings during fall or winter. 

Be careful not to confuse BMSB with western conifer seed bugs, which can be found in homes when it is cold out.  Here is how you can recognize a western conifer seed bug:

  • 3/4 inch long.
  • Oval shaped.
  • White zigzag pattern on back.
  • Leaf-like enlargement on back legs.

You can check out where BMSB has been found on this map from the Minnesota Department of Agriculture (MDA).

If you find a suspected BMSB in a new area, report it to MDA through Arrest the Pest.

Author: Jeffrey Hahn, Extension entomologist

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