Missouri is home to at least nine species of stink bugs, with populations that spike in late summer and fall. Whether you’re finding them clustering on the sunny side of your house, slipping through cracks into your living room, or damaging soybean fields, stink bugs are a widespread presence across the state. Here’s what you’re dealing with and how to manage them.
Species Found in Missouri
A University of Missouri statewide survey spanning the 2024 and 2025 growing seasons collected more than 2,700 stink bugs from 316 commercial soybean fields, representing nine distinct species. The green stink bug dominated, accounting for more than 80% of all specimens. It’s a bright, shield-shaped insect about half an inch to three-quarters of an inch long, with a solid green body and a narrow yellow or orange border along its edges.
The one-spotted stink bug came in second at roughly 10.5% of the total, followed by the brown stink bug at about 5.9%. Each of the remaining six species made up less than 1% of the collection. Two species worth watching, the red-banded stink bug and the brown marmorated stink bug, have both been detected in Missouri soybeans over the past 25 years, though neither is currently widespread. The brown marmorated stink bug turned up in only a few locations and at low levels in the recent survey. The red-banded stink bug wasn’t detected at all.
The brown marmorated stink bug is the one most associated with home invasions nationwide. It’s slightly larger than the green stink bug, mottled brown and gray, with distinctive white banding on its antennae and along the edges of its abdomen. If you’re finding stink bugs indoors during fall and winter in Missouri, this is often the species responsible, though native brown and green stink bugs will also seek shelter in homes.
Why They Show Up in Your House
Stink bugs don’t breed or feed indoors. They enter homes in fall looking for a protected place to spend the winter, a behavior called overwintering. As temperatures drop, they’re drawn to the warm, sun-facing sides of buildings and begin probing for entry points. Once inside wall voids, attics, or crawl spaces, they go mostly dormant. The problem comes on warmer winter days or in early spring, when they wake up and wander into living spaces, often congregating around windows and light fixtures.
This is why you might see dozens appear inside your home over a single warm weekend in February or March, even though you haven’t noticed them in months. They were there all along, tucked into gaps you couldn’t see.
Sealing Your Home Against Entry
Physical exclusion is the single most effective strategy. Stink bugs can squeeze through gaps as small as 1/16 of an inch, so thorough sealing matters. Start with these priority areas:
- Doors: Install door sweeps or thresholds at the base of all exterior doors. Apply caulk along the bottom outside edge and sides of door thresholds. Garage doors should have a rubber bottom seal (vinyl performs poorly in cold weather).
- Windows: Caulk cracks around window frames using silicone or acrylic latex caulk. Repair any gaps or tears in window screens.
- Utility openings: Seal where pipes and wires enter the foundation and siding, including around outdoor faucets, gas meters, dryer vents, and cable lines. Use caulk, cement, expandable foam, steel wool, or copper mesh depending on the size of the gap.
- Vents: Cover attic, roof, and crawl space vents with quarter-inch wire mesh hardware cloth.
- Sliding doors: Line the bottom track with half-inch to three-quarter-inch foam weatherstripping to close gaps beneath the door.
The best time to seal is late summer, before stink bugs begin their fall migration toward structures. Doing it in November means many are already inside your walls.
Removing Stink Bugs Indoors
The cardinal rule: don’t crush them. Stink bugs release a pungent, cilantro-like chemical from glands on their abdomen when threatened or squashed. The smell lingers and can stain fabric and surfaces.
The simplest removal method is a piece of paper or cardboard slid under the bug, then released outside. For larger numbers, a vacuum with a bag works well. Dispose of the bag immediately, or the smell will permeate the vacuum. Some people dedicate a cheap handheld vacuum solely to stink bug duty.
Researchers at Virginia Tech tested a homemade trap that outperformed commercial options costing up to $50. Fill a foil roasting pan with water and a squirt of dish soap, then place a desk lamp directly over the pan in a dark room. The light attracts the bugs, they fall into the soapy water, and the soap breaks the surface tension so they can’t escape. In testing, this setup eliminated 14 times more stink bugs than store-bought traps. It’s pesticide-free and costs almost nothing.
Indoor insecticide sprays are generally not recommended for stink bugs. They don’t prevent entry, dead bugs in wall voids can attract other pests like carpet beetles, and the chemicals pose more risk to you than to the stink bugs.
Stink Bugs and Missouri Agriculture
Missouri ranks as the seventh-largest soybean producer in the United States, with more than 5 million acres planted annually. Stink bugs are a serious economic threat to that crop. Across 19 major soybean-producing states, the stink bug complex is considered the costliest insect pest, with estimated yield losses exceeding 12 million bushels.
Stink bugs feed by piercing soybean pods and developing seeds with their needle-like mouthparts. This reduces yield, damages seed quality, and can delay maturity enough to push back harvest timing. Populations stay low early in the growing season but ramp up quickly once plants reach reproductive growth stages, peaking at full seed development, which is also when the crop is most vulnerable.
The University of Missouri survey found that green stink bug populations were significantly higher along field edges than in field interiors. The bugs typically move into soybean fields from nearby wooded areas, crop residue, and other sheltered habitats before spreading inward. Fields surrounded by diverse landscapes with forests, pasture, and mixed cropland tended to support both higher overall populations and greater species diversity.
For farmers, the treatment threshold combines all stink bug species into a single number: chemical control is justified when sweep net sampling finds an average of 3.5 stink bugs per 15 sweeps in 30-inch rows. Because populations concentrate at field borders, a single border insecticide application at threshold can control brown marmorated stink bugs for the entire growing season. Thresholds for corn have not yet been established.
What Attracts Them to Your Property
Stink bugs are generalist feeders. In Missouri’s landscape, they use a wide range of host plants throughout spring and summer, including fruit trees, ornamental shrubs, garden tomatoes and peppers, and wild plants along wooded edges. Properties near tree lines, hedgerows, or mixed agricultural land tend to see more stink bug activity simply because those habitats support larger populations.
Light is a major attractant at night. Porch lights, garage lights, and illuminated windows draw stink bugs to structures, where they then find entry points. Switching exterior lighting to yellow “bug light” bulbs or warm-toned LEDs reduces attraction. Keeping blinds closed on fall evenings also helps, since interior light visible through windows pulls them toward the glass.
Fruit trees and gardens near the house give stink bugs a reason to linger close to the structure. If you’re growing tomatoes, peppers, or fruit within a few feet of your foundation, you’re essentially staging them for an easy transition from feeding to overwintering inside your walls.