Watch out for the pesky “Brown Marmorated Stink Bug (BMSB)” that sneaks into the homes at this time of the year. In the last few years, the population of BMSB increased in southeast Wisconsin and in several other regions in the state. BMSB is native to Asia (China, Japan, Korea, and Taiwan) and was first detected in 1998 in eastern Pennsylvania. It was first detected in Wisconsin in 2010.
Like any fall invading ladybugs and boxelder bugs, BMSB spend their winter indoors and leave in spring. But BMSB can become more than just a nuisance bug. Under high populations, these bugs can release a stinking odor from their dorsal scent glands and can make indoor settings unhospitable. They can also cause allergic reactions to sensitive individuals. The bug’s frass can stain walls and curtains. If these bugs are squeezed or vacuumed, they emit a stinking vapor that makes it challenging to handle this bug.
The appearance of BMSB is very similar to native stink bug with a shield-shaped body (1/2 to 5/8” long) with a blotchy brown to grayish color. But BMSB has a few key differentiating characteristics: 1) alternating white to brown spots on the outer edge of the abdomen beneath the wings, 2) alternating bands of light and dark brown color near the tips of the antennae, and 3) dark red eyes.
Besides being an indoor nuisance bug, BMSB can affect a wide range of outdoor landscape and garden plants – pears, apples, peach, raspberry, grapes, cherry, currant, field corn, soybeans, dried beans, green beans, sweet corn, pepper, tomatoes, okra, asparagus, basswood, catalpa, silver maples, walnut, roses, serviceberry, viburnum, butterfly bush, and honeysuckle. In Pennsylvania, this bug was reported to cause significant damage to apples and peach production in 2010.
Common entry points for BMSB into our homes include the cracks and crevices of walls, doors, windowsills, attics, and basement floors.
- Check entry doors for any gaps and prevent the entry of the bugs by using door sweeps at the base.
- Plug the utility openings that enter from outdoors and fix any damaged or large holes in door screens.
- Sweep the bugs into a bucket filled with soapy water, causing them to drown.
- Vacuum cleaners can be used to remove the BMSB, but they need to be emptied and tossed outside immediately. But beware that the vacuum cleaner may retain the stinking odor for a period.
- Use of insecticides inside the house is not recommended. Exterior application of insecticides provides temporary relief and should be applied prior to swarming of the bugs.
For more information of BMSB, visit UW Madison Extension Fact sheet: https://hort.extension.wisc.edu/articles/brown-marmorated-stink-bug/
Author: Vijai Pandian, Horticulture Educator