Q: The bugs trying to spend the winter in my home aren’t a hazard, right? I’m going to try to seal up where they may be getting in, but there are already some that have managed to appear inside that would be hard to track down.
A: They don’t bite, aren’t attracted to indoor plants (though they might be drawn to grow lights, as they are to any light source), and are generally just a nuisance. If not easy to find, you can let them wander around until they expire, then dispose of them. Live bugs can be vacuumed or caught and released outside to meet their fate. Boxelder bugs, brown marmorated stink bugs, and multicolored Asian lady beetles are the trio of common culprits here in Maryland. Crickets, pillbugs, and millipedes come inside too, but at least they don’t fly.
Our homes must look like giant boulders to them, basking in the waning sunlight and retaining relative warmth, riddled with inviting crevices in which they can wait out the winter. Our abodes might be especially attractive since our groomed landscapes don’t have as many natural tree cavities, fallen logs, brush piles, or layers of leaf litter to tempt them instead.
If anyone is still puzzled by how they’re getting in, check your door and window weather-stripping for degradation or gaps, look for torn window screening, and inspect vent covers and conduit or pipe entry points on the exterior of the home. Seal any gaps and cracks that you can. If you use a window air conditioner, take it out for the season or plug up any access points around it.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.
I frequently find numerous brown marmorated stinkbugs on certain houseplants so wonder about your statement that they are not attracted
to houseplants. Also, in certain parts of our yard, I notice a strong odor of stinkbugs so wonder if they congregate/live in specific shrubs and trees.
Although there’s a slight chance they might lay eggs on indoor plants while stuck indoors for the winter, the stink bug adults should not take an interest in feeding on the plants, nor is it likely their eggs will hatch or the nymphs survive for long in indoor conditions. Often, when overwintering insects are found among indoor plants, it happens because of the draw of the nearby light source, and not an attraction to the plants themselves. Either the natural light from a window or from grow lights being used attract the stink bugs (and lady beetles, etc.) since most insects are naturally drawn to light in the relatively dim interior of our homes. They can land on and crawl over the plants as they wander, but should not be feeding in any significant way (if at all). At the very least, they tend to be easy to catch and dispatch, in any case.
We can’t say why you notice concentrated scents of stink bug outdoors in certain areas. Perhaps they are congregating prior to overwintering or there are other, unrelated sources of the smell. For example, the caterpillars of some butterflies can produce an offensive odor when disturbed. Stink bugs like the Brown Marmorated Stink Bug tend to be generalists in terms of feeding, though some relatives like Boxelder Bug (which can release odors when disturbed or avoiding a predator) do have host plant preferences.