What’s up with boxelder bugs?
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.
Like many county Extension offices, we are getting many, many calls from homeowners complaining about 1,000’s of tiny blackish red bugs crawling everywhere and over everything. Boxelder bug nymphs are moving through yards and neighborhoods in large harmless, but annoying, swarms.
During the summer, boxelder bugs feed on the flowers and seedpods of female boxelder trees, silver maple and a few other trees and shrubs. The developing nymphs are bright red in color with black markings and are quite nomadic. They can be seen roaming about yards and gardens throughout the summer months. No one can come up with a good reason as to why these bugs roam about. Maybe they’re looking for a new host tree. Maybe they’re sightseeing. Maybe they’re just restless and bored. Or, maybe they’re just a bunch of dumb bugs that crawl about just to annoy us. Who knows!
It is not necessary to control boxelder bug nymphs this early in the summer. These are not the same bugs that will invade our homes in the fall. The nymphs present in late June will mature into adults that will reproduce in late July. It is this second generation of the summer that produces the invading adults of October. If revenge suits you, spraying a persistent insecticide in areas where the nymphs are seen in high numbers can temporarily reduce the population.