Pest control/box elder bugs

Asked March 26, 2016, 12:06 PM EDT

Hi; How do you control these? I know they're not harmful but I have more every year, with the past few mild winters they don't seem to die off as in previous years. I'd rather not use anything toxic but I'd like to know about all options. Do they have any natural enemies? Thanks for your help. Steve

Washington County Oregon

3 Responses

At this time of year, box elder bugs are simply hanging out in a sheltered place to survive the winter. During the winter, box elder bugs are dormant; they don’t feed, breed, or affect people or their pets. The bugs typically return to the same dwelling year after year because their predecessors marked the structure with pheromones that “tells” them it is a suitable shelter. Because they are still dormant during March, insecticides are not helpful.

If you have thousands, one bit of good news is that a wet-dry shop-vac can markedly decrease the population. If some have come indoors, you flick them into soapy water or, again, put that vacuum to good use.

To keep the bugs out of your indoor spaces, block their way. During the fall and winter install or replace weather-stripping, and caulk or seal interior cracks and crevices around windows and light fixtures where they enter your house. But, to avoid sealing the bugs in the wall void, wait until next July to seal cracks and crevices on the exterior of the structure.

Resources for you:

- Understanding and controlling box elder bugs

- Box elder bugs

Thanks for getting back to me Jean; I have a shop vac so I can try that idea. Dish soap in a pray bottle works but with lots of them its time consuming. Thanks for the pheromone info, hadn't thought of that but maybe pressure washing might help. FYI, they're not dormant in March, they're all over the place. Actually past few winters haven't been dormant for more than maybe 1-2 months in the dead of winter. Less of them around for sure, but don't totally disappear like they used to. Thanks again!

I doubt pressure washing would work because the pheromone marking isn't on the exterior. Instead, it's inside the wall void.

Even though the recent winters have been mild, it's true that the insects are dormant. They're most visible on warm days Right now, they're waiting until spring when they will mate, lay eggs, and then die. That may occur this month (April) because everything seems to be ahead of schedule, just as it was during the spring of 2015.

The shop-vac should do a good job of decreasing the current population. But it's impossible to predict how many of the box elder bugs will arrive this fall and winter because the box elder bugs they typically congregate from miles around.