Banishing Boxelder Bugs
By Tim Newcomb, Anoka County Extension Master Gardener
Now that spring has arrived, you might be seeing hundreds of boxelder bugs congregating in or around your house as they emerge from their winter hiding places. Boxelders are native to Minnesota and eat mostly seeds, leaves, and the flowers of boxelder maples and other trees, along with the occasional fall fruit. While they are not considered a garden pest, and they don’t sting, bite, or transmit diseases, it’s their activities in and around our homes that give boxelder bugs their bad reputation.
To manage boxelder bugs, we need to keep in mind their life cycle and behavior patterns. When large numbers of boxelders swarm your house, you might worry that you have an infestation, but the bugs you see have been around all winter and are just coming out of hiding to find food and a mate. While spraying is an option, the University of Minnesota Extension service recommends using physical controls instead. Spraying for boxelders has not proven to be effective, and the chemicals can harm humans, pets, and beneficial insects if used improperly. Remember, boxelder bugs don’t have what they need to survive in your home, so they want to get out as badly as you want them out.
Within a few weeks of escaping, boxelder bugs will mate and lay their eggs in the bark of the boxelder tree. Boxelder bug nymphs will emerge a few days later, and they will feed and grow throughout the summer and then breed a second generation of bugs that will become adults in late summer to early fall. This second generation will then be looking for a place to winter.
In nature, boxelder bugs search for warm and dry places like stumps, debris piles or rocks to hide for the winter. Unfortunately, the marvels of in-home climate control make our homes a prime target for overwintering bugs. Boxelders don’t do serious damage in homes, but their feces can stain lightly-colored objects, and squished bugs will stink. It is difficult for boxelders to find food or water indoors, and this will prohibit them from breeding there.
The best method to get rid of boxelder bugs is to physically remove them with a broom or vacuum. If they swarm the outside of your home, use a hose to clean them off. This is also when you can investigate where the bugs are coming in and seal up any holes. Cleaning up around your home and removing debris or wood piles that may attract boxelders as overwintering locations will also discourage them from coming to your house.
Boxelder bugs are a part of Minnesota’s ecosystem, and since we have moved into their space, we should tolerate occasional (or sometimes frequent) encounters with them. You can even learn to embrace them; the town of Minneota celebrates them during ‘Boxelder Bug Days.’ Another alternative is to get out the vacuum or hose now, and then focus on making your home less attractive to boxelders in the fall. For more information about boxelder bugs, visit Boxelder bug boom | UMN Extension
Meet with an Anoka County Extension Master Gardener volunteer about your yard and garden question! Plant and Insect Diagnostic Clinics: In person at Bunker Hills Activities Center on Wednesdays, June 7 - August 16, from 6 - 8 p.m. Ask a Master Gardener Online: Zoom, first Tuesday of each month, May - December, from 6:30 - 8 p.m. Visit anokmastergardeners.org for more details.