The brown marmorated stink bug is now established in Minnesota, where it shows up most noticeably in fall as it seeks shelter inside homes. This invasive species, originally from East Asia, feeds on over 300 plant species and has become a growing concern for Minnesota gardeners, fruit growers, and homeowners who find clusters of the shield-shaped insects on walls, window frames, and curtains as temperatures drop.
Identifying Stink Bugs in Minnesota
The brown marmorated stink bug is a medium-sized, shield-shaped insect measuring 12 to 17 millimeters long, roughly the width of a dime. It’s brown with darker brown speckles on top and a pale underside, with a head noticeably smaller than its body.
Minnesota also has native stink bug species that look similar, so telling them apart matters. The key feature of the brown marmorated stink bug is the alternating brown and white stripes on its antennae and along the outer edge of its body. Native species like the brown stink bug lack this banding pattern. If you’re finding stink bugs in your home during fall, check the antennae first. Striped antennae confirm you’re dealing with the invasive species.
Garden and Crop Damage
Brown marmorated stink bugs feed by piercing plant tissue with needle-like mouthparts and sucking out fluids. They’re especially drawn to plants with fruits, buds, and pods, which makes orchards and vegetable gardens prime targets. In Minnesota, the crops most at risk include apples, grapes, soybeans, and common garden vegetables.
The damage is distinctive. On apples, feeding creates cork-like dead spots beneath the skin that eventually become sunken, making the fruit unmarketable and unappetizing. On tomatoes and peppers, you’ll see similar discolored, dimpled areas. The bugs don’t consume the entire fruit. Instead, they leave behind cosmetic and structural damage that ruins the harvest. For home gardeners, regular visual inspection of fruit starting in midsummer can help you catch infestations early before they spread across your plants.
Why They Invade Homes in Fall
Stink bugs don’t breed or feed inside your house. They enter in September and October looking for a warm, sheltered spot to spend the winter, a behavior called overwintering. They’re attracted to sun-warmed exterior walls, particularly on the south and west sides of buildings, and then squeeze through tiny gaps to reach wall voids, attics, and crawl spaces. On warm winter days, they sometimes emerge inside the home, crawling across ceilings and congregating near windows, which is when most people notice them.
Keeping Stink Bugs Out of Your Home
Prevention is far more effective than dealing with stink bugs once they’re inside. The goal is sealing every gap they could use as an entry point, ideally before September.
- Windows and doors: Seal cracks around frames with silicone or acrylic latex caulk. Repair torn window screens. Install door sweeps on all exterior doors. A gap as small as one-sixteenth of an inch is enough for insects to get through, so lie on the floor and check for light leaking under doors.
- Garage doors: Fit the bottom edge with a rubber seal to close the gap between the door and the ground.
- Utility openings: Seal gaps where pipes, wires, and cables enter the foundation or siding using caulk, expandable foam, or copper mesh.
- Vents: Install quarter-inch wire mesh (hardware cloth) over attic vents, roof vents, and crawl space openings.
- Sliding doors: Line the bottom track with foam weather stripping, half to three-quarters of an inch wide, to close gaps beneath the door.
Focus your inspection on the sunny sides of the building where stink bugs are most likely to land, and pay close attention to fascia boards, soffits, and anywhere siding meets a different material.
Removing Stink Bugs Safely Indoors
The one thing you want to avoid is crushing a stink bug. The foul smell they release comes from a chemical secretion stored in glands on their underside, and squishing them on carpet, curtains, or walls leaves a lingering odor that’s difficult to remove.
The simplest approach is a vacuum cleaner. Use a hose attachment to suck up individual bugs or small clusters. If you use a bagless vacuum, empty the canister into an outdoor trash bag immediately, or the smell will fill your vacuum. Some people dedicate a cheap handheld vacuum specifically to stink bug duty.
For larger infestations, a homemade light trap works surprisingly well. Virginia Tech researchers found that filling a foil roasting pan with water and a squirt of dish soap, then positioning a desk lamp directly over the pan in a dark room, eliminated 14 times more stink bugs than commercial traps costing up to $50. The bugs fly toward the light, land in the soapy water, and drown. It’s inexpensive and completely pesticide-free, which matters because there are no indoor insecticides labeled for use against brown marmorated stink bugs.
You can also pick up individual bugs with a tissue and flush them, or gently flick them into a jar of soapy water. The key is handling them calmly. They don’t bite or sting, and they only release their smell when they feel threatened.
Are Stink Bugs Harmful to People or Pets?
Stink bugs don’t bite, sting, or transmit diseases to humans. They’re a nuisance pest, not a health threat. Some people with sensitivity to allergens may react to the compounds in their secretions, but this is uncommon.
Pets are a slightly different story. Dogs and cats sometimes eat stink bugs out of curiosity, and while the bugs aren’t poisonous, their secretions irritate the gastrointestinal tract. This can cause vomiting, excessive drooling, and irritation of the tongue, gums, lips, and inner cheeks. There don’t appear to be serious long-term health effects from a pet eating a stink bug, but repeated snacking can mean repeated bouts of drooling and stomach upset. If your dog or cat develops a habit of chasing them, reducing the number of bugs in your living space with the methods above is the practical fix.