What Is Good for Killing Boxelder Bugs?

Hot Water

• Water between 165 and 180 degrees Fahrenheit kills boxelder bugs. However, it can kill grass and plants also, so avoid spraying such hot water on plants or a lawn. Spray the outside of your home with hot water. If getting water hot enough is a problem, simply hosing bunches of boxelder bugs off of walls or trees with room-temperature water will remove them from these objects. Boxelder bugs can easily drown in water.

Shop Vacuum

• Regular indoor upright vacuums should not be used for killing boxelder bugs, warns Clemson University Horticulture Extension Agent J. MacLeod Smith. These bugs emit a foul odor when they are vacuumed, and this odor can stay in your vacuum cleaner. It is much easier to clean a shop vacuum or add hot water and a few drops of dish detergent inside of the shop vacuum to kill the bugs and help remove any odor. Empty the shop vacuum into an outside garbage container as soon as possible to remove the stench from your home.

Exterior Pyrethroid Sprays

• Pyrethroid sprays should be used on the outside of the home only in the late fall when large numbers of boxelder bugs congregate to search for hibernation places. Insects must come into contact with the spray in order to die. Types of insecticides that kill boxelder bugs include bifenthrin, permethrin, deltamethrin and cyfluthrin. Never spray boxelder bugs in the early spring, as these insects won't enter the home, instead flying off in search of plants and seeds to eat. Killing them in the spring won't stop other boxelder bugs from entering a building in the fall.

Laundry Detergent Sprays

• Laundry detergent is a better alternative than an over-the-counter insecticide spray or aerosol for boxelder bugs already inside your home . Mix liquid or powder laundry detergent and water in a spray bottle. Shake before using and spray any boxelder bugs you see. Avoid spraying those that are on houseplants, though, because the laundry detergent spray may harm the plant.