Box elder bug.jpg
Photo by Bruce Marlin – Own work: http://www.cirrusimage.com/bugs_box_elder.htm, CC BY-SA 2.5, Link
Boxelder bugs are a nuisance pest which can come indoors when seeking warmth. They are black with orange markings and are about 1/2 inch long as adults.

Boxelder bugs are not a significant threat but their fecal matter can leave stains and if crushed they create an objectionable odor.

Once indoors they are best handled by physical means such as a vacuum or broom and dust pan. They don’t very long so spraying them with insecticide is not needed or recommended particularly if you do not want chemicals inside. They do not reproduce inside so there is no concern for a long-term infestation.

The best way to keep them out is prevention by sealing up gaps, weather stripping, loose or torn window screens, etc. Door sweeps at the bottom of doors is also effective.

Spraying outdoors or around your lawn is not likely to affect subsequent year population or activity because they can fly several miles so your home or neighbor’s home may not be the source.

If you do have get regular boxelder invasions, a general pest control treatment just around your home can help but the best time to do so is typically late summer or fall.