Skip to main content

Nuisance Insects In Fall

Jeffrey Hahn, Asst. UMN Extension Entomologist

boxelder bug Jeff Hahn.jpg
Boxelder bug
Jeff Hahn
As the days get shorter and the days and nights get cooler, this is a cue to people that summer is ending and fall is upon us. That is also a sign for insects, signaling them that they need to prepare for winter. For some insects and related arthropods, this means finding sheltered places to overwinter which unfortunately can mean our homes.

Some insects, particularly boxelder bugs, multicolored Asian lady beetles, cluster flies, and hackberry psyllids, will fly to buildings and congregate on the outside, especially on the south and west facing exposures where it is the sunniest. As they find spaces and cracks to get inside, some end up in attics, wall voids, and other spaces (where they remain until a mild winter day or spring) while others find their way into the interior part of homes. Yet other arthropods, such as sowbugs, millipedes, and crickets, don't fly but crawl to buildings and find their way indoors at ground level.

Sowbugs under log
Jeff Hahn
Regardless of which nuisance invader you find in your home, the good news is that they do not reproduce indoors and are essentially harmless to people and property. They are short-lived indoors, although some, like boxelder bugs and multicolored Asian lady beetles, can successfully overwinter and can move into the inside of homes periodically during mild winter days and in spring.

The best management of nuisance invaders is prevention; take steps to keep these insects and arthropods out of your home to begin with. First, examine the outside of your home for possible entry points that they may use to enter your home. Look particularly around windows, doors, where utility lines enter buildings, and areas of buildings where vertical and horizontal surfaces meet. If you are dealing with flying insects, concentrate your efforts on the south and west facing exposures. If you are dealing with crawling insects, check for mulch, leaves, and other possible debris close to the building that may provide harborage. Removing this will make it more challenging for them to get inside. It isn't possible to insect-proof your home so that nothing can get in, but it is possible to minimize the number of insects and other arthropods that can into your home.

Multicolored Asian lady beetles trapped indoors
Gail Felton
You can supplement your pest proofing efforts by using an insecticide to treat areas where insects and other arthropods are most likely to enter homes. Treat just as you are starting to notice insects coming indoors. Examples of insecticides that you can use, include products that contain bifenthrin, cyfluthrin, deltamethrin, and permethrin. Be sure that the particular product you wish to use is specifically labeled for use around the exterior of buildings.

Once insects and other arthropods get inside, you do not have many options other than to physically remove them with a vacuum or broom and dust pan.
Print Friendly and PDF