Seasonal Pests — Kansas City
Fall Invaders Are Coming: Boxelder Bugs, Stink Bugs & Cluster Flies
By Joe Cusic, owner and licensed applicator (Kansas #309053 · Missouri #C29778)
Updated July 23, 2026
Every year, right as temperatures start dropping, Kansas City homes see the same wave of unwanted guests looking for a way inside to overwinter. Here's how to get ahead of it.
Why These Three Pests Show Up Together
Boxelder bugs, stink bugs, and cluster flies are all "overwintering pests" — insects that don't die off in winter but instead look for a protected space to go dormant until spring. As outdoor temperatures drop, they migrate toward the warmest, sunniest side of a building (usually south- or west-facing walls) and work their way into any gap they can find: siding seams, soffits, window and door frames, utility penetrations, and attic vents.
Once they're in the wall void or attic, they stay put through winter. The real problem hits on warm winter days or in early spring, when the same pests wake up and end up inside living spaces instead of staying in the wall — which is when most homeowners actually notice they have hundreds of them.
Why It's Worth Handling Before It Starts
By the time you're finding boxelder bugs on your windowsill in November, they're already inside the structure. At that point you're managing symptoms room by room instead of preventing the entry in the first place. Sealing gaps before the fall migration starts is what lasts; a timed exterior treatment helps with the ones already on the walls. For identification and detail on each species, see our boxelder bugs, lady beetles and stink bugs guide.
What Actually Helps
Seal likely entry points now
Check siding gaps, window and door frames, utility line penetrations, and attic and soffit vents. These pests are flat and small enough to fit through gaps most homeowners wouldn't think twice about.
Address the source
Boxelder bugs are drawn to boxelder, maple, and ash trees nearby. A heavy population on a specific tree is often the staging ground before they move to the house.
Time a perimeter treatment for early-to-mid fall
A treatment on the sunny walls where they gather reduces the numbers that get in — but sealing is what lasts. Treatment alone is short-term.
Don't wait for a “small” problem
A few boxelder bugs on a warm September afternoon are often the first sign of a much larger population about to move in as it cools off.
Get Ahead of Fall Invaders
All Star Pest Solutions treats for fall invaders before they establish themselves in the wall voids and attics of Kansas City homes — not after. Text a photo of what you're seeing on the siding and we'll help you figure out if it's worth acting on now.
FAQs
Why do boxelder bugs and stink bugs show up in fall?
As outdoor temperatures drop, these insects look for a protected space to go dormant through winter. They migrate toward the warmest, sunniest side of a building and work their way in through siding seams, soffits, window frames, and utility penetrations.
When should I treat my house for fall invaders?
Early-to-mid fall, before the migration peaks. Sealing gaps is what lasts; a timed exterior treatment on the walls where they gather handles the insects already massing there, but on its own it is short-term.
Are boxelder bugs and stink bugs dangerous?
No — they don't bite, sting, or spread disease. They're a nuisance pest, but large populations clustering on siding or getting into living spaces on warm winter days can still be a serious annoyance.