Long and black with red accents, box elder bugs are not incredibly dangerous. However, they are definitely a nuisance. They smell, they can leave stains on light-colored building materials, and when they show up, they show up in droves. If you're dealing with an infestation of these bothersome pests, here are some strategies to help you get rid of them.
Spray them with soapy water
This is a good strategy to try first since it doesn't call for any pesticides or potentially dangerous chemicals. Just mix some dish soap into a bottle of water, and spray the bugs down. Make sure you saturate them well. The soapy water is usually heavy enough to cause the bugs to fall down off the surface they've been clinging to. The soap will make it harder for the bugs to cling to the same walls again.
Apply diatomaceous earth to the ground
Diatomaceous earth is a fine powder that is made from the exoskeletons of tiny, sea-dwelling creatures. It is safe for humans (although you won't want to inhale large quantities of it), but deadly to insects. This is because it basically dehydrates insects and puts holes in their protective exoskeletons. Scattering some diatomaceous earth on the ground in areas where you see box elder bugs can kill some of them and help keep their numbers down. The main challenge here is that diatomaceous earth does become far less effective as it absorbs water. So, you'll need to reapply it often — maybe daily — to keep the box elder bugs under control.
Marigolds have a strong scent that many bugs, including box elder bugs, tend to find unappealing. Planting marigolds alone probably won't keep box elder bugs away completely. However, it should help. You can even buy a few pots of marigolds and just set them out in the spots where the box elder bugs have been gathering.
Have insecticides sprayed
With bad infestations, sometimes the only real solution is to have your home sprayed with insecticides. A pest control company can use a relatively mild solution since box elder bugs tend to be quite sensitive to these chemicals. You'll want to make sure your doors and windows are closed during the treatment so the insecticides don't make their way inside. Usually, one application in the late spring is enough.
Box elder bugs aren't terribly dangerous, but they are a nuisance nonetheless. Call a pest control company near you for help with box elder bugs and other pests.