Stink bugs live outdoors on trees, crops, and garden plants during warm months, then move into homes and other sheltered structures when temperatures drop in fall. The most common species in the U.S., the brown marmorated stink bug, is native to East Asia and has spread to most of the continental United States since arriving in Pennsylvania in the mid-1990s.
Native Range and Global Spread
The brown marmorated stink bug is native to China, Japan, and North and South Korea. Researchers believe the original population that reached the U.S. came from northern Japan or western Korea. The first confirmed specimen in North America was collected in Allentown, Pennsylvania in 1998, though it likely arrived a few years before that. From that single foothold, the species spread rapidly across the eastern U.S. and eventually to the West Coast. A 2005 detection in Vallejo, California was traced to a resident who had relocated from Pennsylvania.
The bug has gone global. It was first reported in Europe near Zürich, Switzerland in 2008 and has since appeared in several other European countries. In 2010, an individual turned up in South Dunedin, New Zealand, apparently introduced via a used vehicle shipped from Tokyo. Today, it is found throughout most of eastern and western North America, and entomologists at Penn State expect it to eventually be present continent-wide.
Where They Live Outdoors
During spring and summer, stink bugs are plant feeders. They live on a wide range of host plants, including fruit trees, vegetable crops, soybeans, and ornamental shrubs. Different species have slightly different preferences. Green stink bugs are the dominant species in vegetable and soybean fields across much of the mid-Atlantic. Rough stink bugs (sometimes called tree stink bugs) prefer fruit trees and other hardwoods, though they occasionally show up in crop fields. Brown marmorated stink bugs are the least picky of the group, feeding on more than 100 different plant species including apples, peaches, tomatoes, peppers, and beans.
In the wild, their natural sheltering spots include rocky outcroppings and standing dead trees with loose, thick bark, particularly oak and locust trees. These structures provide the cool, dry crevices that stink bugs seek out when it’s time to hunker down for winter.
Why They Move Into Homes in Fall
As days shorten and temperatures cool in autumn, stink bugs begin searching for protected spots to spend the winter. Buildings are ideal substitutes for the bark crevices and rock gaps they would use in nature. On warm fall days, you’ll often see them clustering on the sunny, south-facing sides of houses before finding their way inside.
Those clusters aren’t random. When one stink bug finds a good spot, it releases an aggregation pheromone, a chemical signal that attracts others to the same location. This is a different compound from the foul-smelling liquid they release when threatened. The aggregation scent is why you might see dozens or even hundreds of them gathered in one area of your home’s exterior while your neighbor a few doors down has almost none.
Where They Hide Inside Your Home
Stink bugs enter through cracks and gaps around windows, doors, roof flashing, vents, window air conditioners, fascia boards, and siding. They strongly prefer the upper parts of a building, often getting in through attics and chimneys. Once inside, they tuck themselves into crevices in walls, ceilings, and attic spaces. Unheated attics are their most common indoor hiding spot. Crawlspaces and basements are much less appealing to them because those spaces tend to be damp rather than dry.
They also overwinter in garages, outbuildings, vehicles, outdoor HVAC units, and even gas grills. Basically, any structure with a gap large enough to squeeze through and a sheltered interior is fair game. You may not notice them for weeks or months. They enter a dormant state called diapause, staying still and quiet inside wall voids or behind baseboards. Then on a warm winter day, or when spring arrives, they become active again and start showing up inside living spaces, often disoriented and buzzing around windows and light fixtures.
What They Don’t Do Indoors
Stink bugs are not nesting in your house the way ants or mice would. They don’t reproduce indoors, don’t eat your food or belongings, and don’t cause structural damage. They’re purely sheltering. The annoyance is their sheer numbers and, of course, the smell they release if you crush or vacuum them. Once they emerge from overwintering in spring, they head back outside to feed and mate on plants. Your home is a hotel, not a habitat.
Keeping Them Out
Because stink bugs exploit small openings, the most effective strategy is sealing entry points before fall. Caulk gaps around windows and door frames, repair torn screens, cover attic vents with fine mesh, and check the seals around pipes and utility entries. Pay special attention to the upper portions of your home, since that’s where they concentrate.
If they’re already inside, a vacuum cleaner is the simplest removal tool, though the smell can linger in the vacuum bag. Flushing them down the toilet or dropping them into soapy water avoids the odor problem. Pesticide sprays inside the home are generally ineffective because the bugs are hidden deep in wall voids where sprays can’t reach, and killing them inside walls can attract carpet beetles and other scavengers that feed on dead insects.