Why Do I Have Boxelder Bugs and How to Prevent Them in the Fall

Just because they don’t bite, it doesn’t make them less of a nuisance. Boxelder bugs can enter your home in large numbers during the fall, staining curtains, walls, and other surfaces with their excrement.

During summer, boxelder bugs feed on leaves, flowers, and seedpods of boxelders and silver maples, where they do minor damage to the trees. During fall, they search for protected areas for the winter, or overwintering areas, as they leave the trees from where they were feeding. They like warm areas and are attracted to buildings with large southern or western exposure, with lots of sun. They also like buildings standing isolated on flat ground, or buildings which are taller than surrounding structures.

Cool weather brings bugs in

Once the weather starts to cool down, boxelder bugs find their way into spaces and cracks around homes. This is usually how they end up around windows in the interior of buildings. They can also come in the building from overwintering areas such as attics or walls. They are typically inactive during winter, unless the weather is mild and sunny, which increases their mobility.

Boxelder bugs are most abundant during hot, dry summers when followed by warm springs. Wet weather promotes a fungal disease which controls the population of boxelder bugs. Since we have had a long dry spell in Wisconsin, we might see a lot of these bugs this fall. We have also had a longer, warmer weather season this year, which has caused the boxelder bugs from the spring to mature more quickly and sprout an early second generation. It is these second generation bugs that become a nuisance by congregating on the outsides of homes and buildings on sunny days in September and October.

The best way to manage a boxelder bug problem is to prevent it by taking steps to keep them from entering your home in the first place.

Boxelder bug prevention outdoors:

• Repair or replace damaged window and door screens
• Repair or replace damaged screens in roof vents, and in bathroom and kitchen fans
• Seal areas where cable TV wires, phone lines, and other utility wires and pipes, outdoor faucets, dryer vents and similar objects enter buildings
• Install door sweeps or thresholds to all exterior entry doors
• Install a rubber seal along the bottom of garage doors

Depending on the construction of your home or building, different precautions may be taken. If boxelder bugs have already made their way indoors, you may physically remove them with a broom and a dust pan, or a vacuum. Check around the building exterior if they are found during fall, as they can be found congregating in warm or sunny areas.

If you are experiencing a pest problem, don’t hesitate to give us a call at 262-797-4160 or contact us. We are always happy to help.