With the first cold days they turn up on curtains, window frames and ceilings: these are stink bugs in the house, above all the brown marmorated stink bug, which arrived from Asia and is now present in several parts of Spain, as well as the familiar green stink bug. They don't bite or damage furniture, but they're a nuisance and, if squashed, they release a smell that's hard to get rid of. Here's why they come in right now, how to keep them out and how to get them out of the house without leaving a trace.
Why there are stink bugs in the house in autumn
Stink bugs don't come in to feed or breed: they're looking for shelter to spend the winter. When temperatures drop, they gather on the sunniest walls of the building and squeeze through any gap towards a dry, mild spot. Indoors they spend the winter almost motionless, and in spring they try to get back out.
That's why it pays to look for them in the right places: in the folds of curtains, behind pictures, in the high corners of rooms, in roller shutter boxes and, if you have them, in the storeroom or garage, where you sometimes find dozens clustered together.
How to recognise the brown marmorated stink bug
The brown marmorated stink bug is just over a centimetre long, with a shield-shaped, mottled brown body, light bands on its antennae and alternating light and dark stripes along the edge of its abdomen. The green stink bug has a similar shape but is bright green. Neither is dangerous to people: the only real problem is the smell they give off when they feel threatened.
How to keep them out: 6 measures
- Well-fitted insect screens on the windows you open most, especially on south- and west-facing walls.
- Sealed gaps: check the joints around doors and windows and fill cracks with silicone or draught excluder strips. It also helps against the cold, as we explain in our tips for heating your home without heating.
- Roller shutter boxes and pipe openings, such as the one for the air conditioning: they're classic entry points. Close them with foam or brush draught excluders. Always keep the mandatory ventilation grilles for gas boilers and cookers clear.
- Washing on the line: shake out each item before bringing it in. Stink bugs love the folds of clothes drying in the sun.
- Clean windowsills and shutters: wipe them often in autumn, because that's where they gather before coming in.
- Natural remedies, with caution: some people spray garlic water on windowsills. The effect is limited and has to be repeated often. If you have a cat, avoid essential oils in the areas it walks through: many are not recommended for cats.
How to remove stink bugs without squashing them
- Jar of soapy water: hold a jar of water with a few drops of washing-up liquid under the bug and give it a gentle nudge: it falls in without you having to squash it, which is when it releases the most smell.
- Vacuum cleaner with a stocking: put a nylon stocking inside the tube and secure it with a rubber band. The bugs stay in the stocking, which you empty outside without the smell lingering in the machine.
- Glass and paper: for a single bug, a glass and a sheet of paper are enough: cover it with the glass, slide the paper underneath and release it out of the window.
- Insecticide sprays: they're of little use against the ones that are already inside. If you use them, follow the label and take care if there are children or animals at home.
If you have dogs or cats at home
Cats in particular see stink bugs as the perfect toy. If they bite one, they may drool for a few minutes because of the unpleasant taste. Remove any you see on the floor and, if you notice repeated vomiting or your pet seems listless, call the vet.
The good news is that in spring the stink bugs leave on their own. In the meantime, well-sealed gaps will save you almost all the work. And to make your home more comfortable this autumn, take a look at Velia Select's products.