Why Stink Bugs Pile Into Ellicott City Homes Every Fall
Stink bugs pile into Ellicott City homes every fall for a simple reason: they're looking for a sheltered, warm place to spend the winter, and a house is the warmest, most crack-filled thing around. The brown marmorated stink bug arrived from Asia, spread through the Mid-Atlantic, and by around 2010 the Maryland Department of Agriculture was calling it both a homeowner nuisance and a farm pest. Howard County, with its mix of woods, gardens and houses, has been stink bug country ever since.
They're harmless to people and to the house. They don't bite, they don't sting, they don't eat wood or wiring, and they don't lay eggs indoors. But a few hundred of them in the attic and the window frames gets old fast.
A stink bug year, month by month
Spring and summer, stink bugs live outside, feeding on fruit trees, tomatoes, peppers, ornamental trees and just about any garden plant. You'll see a few on the deck rail or the tomato cage and not think much of it. In September, as the days shorten, they start looking for winter shelter. In the woods, that's under bark or in a dead tree. Near a house, it's the siding. By late September and into October, the sunny south and west walls are covered on warm afternoons, and they start crawling into every gap they can find.
Once inside, they settle into wall voids and the attic and go quiet. On mild winter days, the attic warms up and some of them wake, wander toward light and turn up on windows and lampshades. That keeps going into spring, when the survivors try to get back outside. Seeing a few in February doesn't mean new ones are getting in. It's the October crowd.
Where they sneak in on old houses and new ones
The University of Maryland Extension's advice is the same a tech will give you: check weather-stripping on doors and windows, look at vent covers, and seal where pipes and wires come through the wall. On older houses, like the stone and frame homes around the old town near Main Street and the Victorian streets in Catonsville, old window sashes, gaps at the eaves and loose trim let them in by the hundreds. On newer houses, check the ridge vent, gaps at the edges of stone veneer, the many window openings and the spot where the AC line goes through.
- Screens on attic, soffit and gable vents
- Caulk around window and door trim on the sunny sides
- Door sweeps and weather-stripping that actually touch
- Sealing around the cable, AC lines, dryer vent and hose bib
- Window screens without tears
Vacuum, soapy water, and what not to bother with
For the ones already inside, a vacuum works well. Empty it outside right away so the smell doesn't stay in the bag, or slip a knee-high stocking inside the hose to catch them and toss it. A jar of soapy water is a fine low-tech option: knock them in and they drown. Don't squash them, especially on fabric. The smell lingers, and some people find it stains.
Bug bombs and indoor sprays don't reach bugs tucked into the walls, and they leave residue around kids and pets for little benefit. Light traps catch a few, but they don't change the overall number much.
When it makes sense to call
The time to call is late August or early September, before they move in. A tech can treat the outside walls, focusing on the sunny sides, window and door trim, eaves and rooflines, and point out the gaps that need sealing. After mid-October, most of them are already in the walls, and there isn't much to do but wait until next year. Our page on stink bug control in Ellicott City explains how that visit usually goes.
The same gaps that let stink bugs in let mice in a few weeks later, so many homeowners pair the two jobs. Mouse-proofing before the first frost uses the same caulk gun and mesh. If several pests come through every year, ask about a seasonal general plan that times the visits for you. The larger newer homes around Clarksville, with lots of south-facing glass, tend to get some of the biggest crowds.
Questions We Get
Do stink bugs lay eggs in the house?
No. They spend the winter resting. They lay eggs outdoors on plants in spring and summer.
