Why Didn’t We See Stink Bugs in Tennessee Back in the ’80s?
If you grew up in Middle Tennessee in the 1980s, you probably don’t remember brown, shield-shaped bugs crawling up the curtains every October. That’s not your memory playing tricks. The stink bug that shows up on Tennessee homes every fall wasn’t here yet.
The short answer: they hadn’t arrived yet
Tennessee has always had stink bugs. Native species like the green stink bug and the brown stink bug have lived in our fields and gardens for generations (UT Extension). But they stay outdoors. The one covering your windows and siding is a different insect: the brown marmorated stink bug.
It’s native to eastern Asia. It was first identified in the United States in Allentown, Pennsylvania, in 1998, and experts believe it had been there since about 1996 (UT Extension). It reached Tennessee years later: the first record was in Knox County on October 30, 2008, and it’s now well established across the state. Davidson County had its first sighting in 2012 (WKRN).
So it spread from Pennsylvania to Tennessee in about a decade. Two reasons it moved so fast: adults are strong fliers that can travel more than a mile, and they hitchhike on cars, trucks, and shipments (University of Kentucky Entomology). They also arrived without the natural enemies that keep them in check in Asia, which helps them outcompete native stink bugs (StopBMSB.org).
Why you’re seeing them right now
Brown marmorated stink bugs spend the winter as adults, tucked away somewhere sheltered. As days get shorter in the fall, they start searching for those overwintering spots, and buildings are high on the list (Scientific Reports).
A USDA research entomologist told WKRN that this movement starts around the fall equinox and usually peaks between September 21 and about October 5, with stragglers into mid- to late October depending on the weather (WKRN). That’s why early October is when many Middle Tennessee homeowners notice them gathering on the warm, sunny sides of the house.
What draws them inside
Stink bugs aren’t coming in for food. They want cool, dry, protected places to wait out the winter. In nature, that means loose bark on dead trees or rocky outcrops. In your house, it means the cracks and wall voids around windows, doors, siding, and attics (University of Kentucky Entomology).
Once one stink bug finds a good spot, it gives off a chemical that attracts others, which is why a few can quickly become dozens (National Pesticide Information Center). Most stay hidden in walls and attics all winter. The ones you see crawling around inside on a warm winter day, or in early spring, are usually lost bugs trying to get back outside. Outdoors, they mate and lay eggs on plants from late spring through summer (UConn Extension).
Why do stink bugs stink?
It’s self-defense. When a stink bug feels threatened, gets handled, or is crushed, it releases chemicals called aldehydes from glands on its underside (UConn Extension). The two main compounds behind the smell, trans-2-octenal and trans-2-decenal, work as an alarm signal that keeps predators away (PMC).
The good news: stink bugs don’t bite, don’t sting, and don’t damage your home’s structure (National Pesticide Information Center). They’re a nuisance, not a danger, though the odor can irritate sensitive skin and eyes.
Bad news for gardens, too
Outdoors, brown marmorated stink bugs are a real problem for anyone who grows food. They feed on fruits, nuts, vegetables, and ornamental plants, and they prefer to pierce fruits, buds, and pods (Tennessee State University Extension). They also damage many common landscape plants around Tennessee homes (UT Extension). If your tomatoes, peppers, or fruit trees have had a rough year, stink bugs may be part of the reason.
Does the weather make a difference?
Yes. Brown marmorated stink bugs don’t handle hard cold well. Large numbers die when winter temperatures routinely drop below 10°F, which is why they look for sheltered spots in the first place (University of Kentucky Entomology). Researchers have also found that their winter survival improves as average winter temperatures rise (StopBMSB.org). Mild Middle Tennessee winters, especially when they’re tucked inside a wall, give them good odds.
Weather sets the calendar, too. In spring, they come out of hiding and start feeding once temperatures climb above about 63°F (StopBMSB.org). In fall, a long, warm stretch can drag out the season before the first real cold snap. Weather drives plenty of other pest activity too, as we covered in our post on this year’s record-dry September.
Stink bugs aren’t the only newcomer
Plenty of bugs Middle Tennesseans see today weren’t part of growing up here. The kudzu bug, another Asian import, was first found in Georgia in 2009 and reached Tennessee in 2012. Like the stink bug, it likes to move into houses in the fall to spend the winter (UT Extension). Asian lady beetles are another fall invader that crowds onto sunny walls this time of year (see our lady beetle guide). We’ll be covering more of these newer neighbors in future posts.
What to do if stink bugs are getting in
- Seal the gaps. Caulk cracks around windows, doors, siding, and where pipes and wires enter the house. Repair torn window screens and add weatherstripping. Sealing up is the most effective way to keep them out (National Pesticide Information Center).
- Remove them quickly. Stink bugs inside give off chemicals that attract more of them to the same spot (National Pesticide Information Center).
- Vacuum, don’t squash. Crushing one releases the odor. Vacuum them up and throw the bag away (or empty the canister outside) so the smell doesn’t linger (UConn Extension).
- Don’t wait until they’re inside. Once stink bugs are in your walls, they’re hard to reach. Prevention works best in late summer and early fall, before they start moving in.
How U.S. Pest helps
Stink bugs are covered on all of our home pest control plans, along with lady beetles and other fall invaders. Each visit includes an exterior treatment around the places stink bugs gather and get in, like eaves, windows, doors, and siding, timed to stop them before they settle into your walls. During your free inspection, your technician will also point out the gaps and entry points worth sealing.
Learn more in our stink bug identification guide, or compare our monthly, every other month, and quarterly plans. Every plan is backed by our Whatever It Takes Guarantee. Call 615-590-1260 or schedule a free inspection.
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FAQs
Why didn’t we have stink bugs in Tennessee in the 1980s?
The stink bug that invades homes today, the brown marmorated stink bug, is an invasive species from Asia. It wasn’t identified in the United States until the late 1990s and wasn’t recorded in Tennessee until 2008. Native stink bugs have always lived here, but they stay outdoors.
Why are there so many stink bugs on my house in the fall?
Shorter days in early fall trigger stink bugs to look for sheltered places to spend the winter. Their movement onto homes usually peaks from late September into early October, and each one that finds a good spot gives off a chemical that draws in others.
Do stink bugs bite or damage homes?
No. Stink bugs don’t bite, sting, or cause structural damage. Their odor can irritate sensitive skin and eyes, so it’s best not to handle them.
Why do stink bugs smell?
When they feel threatened or are crushed, stink bugs release defensive chemicals from glands on their underside. The smell warns predators to stay away.
Will stink bugs lay eggs in my house?
No. Stink bugs come inside to wait out the winter, not to breed. They mate and lay eggs outdoors on plants from late spring through summer.
What’s the best way to get rid of stink bugs?
Seal cracks and gaps before fall, vacuum up any that get inside instead of crushing them, and have the outside of your home treated in late summer or early fall before they move in. All U.S. Pest home plans cover stink bugs.
