Indiana is home to nearly a dozen stink bug species, and the one you’re most likely noticing is the brown marmorated stink bug, an invasive pest that migrates into homes by the hundreds each fall. These shield-shaped insects don’t bite, sting, or damage your house, but they release a pungent odor when disturbed or crushed, making them one of the most unwelcome seasonal houseguests in the state.
Species You’ll Find in Indiana
The brown marmorated stink bug gets the most attention, but it’s far from the only species in the state. Indiana falls within the North Central Region, which hosts at least nine pest species and two beneficial ones. Knowing which bug you’re looking at helps you gauge whether it’s a household nuisance, a garden threat, or both.
The brown marmorated stink bug is mottled brown with distinctive white bands on its antennae and black-and-white striping along the edges of its abdomen. Its wing veins are outlined in black. This is the species most likely to show up inside your home in large numbers.
The green stink bug is bright green with a yellow outline and black spots around the abdomen, plus black bands on its antennae. It’s a major pest on soybeans and garden plants across Indiana. The brown stink bug looks similar in size but is dull brown with rounded shoulders and a small row of spines. Flip one over and you’ll see a yellowish-green or pink underside.
A few smaller or less common species round out the list. The twice-stabbed stink bug is easy to identify: it’s black with a red band across its shoulders and two red marks on its back, and it’s noticeably smaller than other species. The redshouldered stink bug is green with a pink or red stripe across the shoulders in summer, then shifts to brown in fall. The rice stink bug has an unusually elongated body and forward-pointing shoulder spines, setting it apart from the wider, more rounded species.
A Common Lookalike: The Western Conifer Seed Bug
Many of the bugs people assume are stink bugs are actually western conifer seed bugs. These insects also invade Indiana homes in fall and have a similar brown, mottled appearance. But they’re longer and narrower than stink bugs, measuring about three-quarters of an inch. The easiest giveaway is their hind legs, which have flattened, leaf-like flares that no stink bug species has. They also display a dark “X” pattern across the back where their wings overlap. Like stink bugs, they’re harmless to people and structures, but telling them apart helps you choose the right approach if you’re dealing with a recurring problem.
When They Move Indoors
Stink bugs start seeking shelter earlier than most people expect. In Indiana, adults begin congregating on the sunny sides of buildings in September, with peak migration into homes running through October. They typically arrive on warm, sunny afternoons, clustering around windows, door frames, and south- or west-facing walls before finding their way inside through small gaps.
Once inside, they tuck themselves into wall voids, attics, and crawl spaces to ride out winter in a dormant state. They don’t eat, breed, or cause structural damage during this time. The second wave of annoyance comes in spring, from March through May, when warming temperatures trick overwintering bugs into “waking up.” Disoriented by indoor heat, they often emerge inside living spaces rather than finding their way back outside.
Damage to Crops and Gardens
Stink bugs are a real economic concern for Indiana farmers and home gardeners. They feed by piercing plant tissue with needle-like mouthparts and sucking out fluid. On soybeans, one of Indiana’s top crops, this feeding punctures developing pods and creates hardened, knotty spots. Pods may drop from the plant entirely. Seeds that survive often come out smaller, shriveled, and discolored, lowering the grade and value of the harvest. Damaged seeds can also produce stunted seedlings if planted the following year.
Green stink bugs are the primary culprits on soybeans. They prefer wild host plants like native trees, shrubs, and weeds, but as those plants dry out in late summer, the bugs migrate into crop fields and gardens. Home gardeners growing tomatoes, peppers, beans, and fruit trees may notice similar feeding damage: dimpled, discolored spots on fruit and vegetables where the bugs have been feeding.
Sealing Your Home Before Fall
Physical exclusion is the single most effective strategy, and the work needs to happen in August or early September, before migration begins. Focus on the gaps stink bugs actually use to get inside:
- Utility penetrations: Seal gaps around pipes, wires, and cables where they pass through exterior walls using silicone or silicone-latex caulk.
- Siding and fascia: Check where siding meets the foundation and where wood fascia boards join the roofline. Even quarter-inch gaps are wide enough for entry.
- Chimneys and vents: Install fine mesh screens over chimney openings and attic vents.
- Windows and doors: Repair or replace torn window and door screens. Check weather-stripping for gaps and add door sweeps to exterior doors that don’t seal tightly at the bottom.
- Mortar joints: Inspect brick and stone exteriors for crumbling or loose mortar, especially around the foundation.
This work pays off for years, since the same entry points that let in stink bugs also admit lady beetles, cluster flies, and other overwintering pests.
Removing Stink Bugs Already Inside
The cardinal rule with indoor stink bugs is to avoid crushing them. The defensive chemical they release smells like concentrated cilantro mixed with burnt rubber, and it lingers. A vacuum cleaner with a bag (not bagless) is the fastest manual option. Dispose of the bag promptly, or the odor will seep out.
For larger infestations, a homemade light trap outperforms commercial alternatives. Virginia Tech researchers tested a simple setup: a foil roasting pan filled with water and a few drops of dish soap, placed in a dark room with a desk lamp shining directly over it. The bugs fly toward the light, land in the soapy water, and drown because the soap breaks the surface tension. In testing, this trap caught 14 times more stink bugs than store-bought traps costing up to $50. The total cost is essentially zero if you already have a pan, soap, and a lamp.
Run the trap at night in rooms where you see the most activity, especially attic spaces, spare bedrooms, or rooms with large windows. Over a few evenings, you can significantly reduce the population that emerged indoors for spring. Indoor insecticide sprays are generally not recommended. They don’t prevent new bugs from waking up inside walls, and dead bugs in hidden spaces can attract carpet beetles and other secondary pests.
Are Stink Bugs Harmful to People or Pets?
Stink bugs pose no health risk. They don’t bite, sting, suck blood, or transmit any diseases to humans or pets. They don’t bore into wood or damage building materials. Some people with allergies report mild irritation from handling large numbers of them, likely a reaction to the defensive compounds on the bug’s surface, but this is uncommon. The smell is unpleasant but not toxic. The biggest consequence of a stink bug infestation is the nuisance factor: finding them crawling on curtains, buzzing around light fixtures, and occasionally landing on you while you sleep.