BOXELDER BUGS - Info, Advice & Help

How to Identify, Prevent & Control Boxelder Bugs in Ontario Homes and Cottages

Quick Facts About Boxelder Bugs

• Common in Ontario, especially near boxelder, maple, and ash trees.

• Harmless to humans and pets but can become a major nuisance in large numbers.

• Most active in late summer and fall as they gather on warm walls and try to enter homes.

• Do not reproduce indoors, but overwintering adults may emerge in winter seeking warmth.

Common Signs of a Boxelder Bug Issue

• Large clusters of bugs on sunny exterior walls, windows, or siding.

• Bugs entering through cracks, vents, or poorly sealed windows in fall.

• Dead or sluggish boxelder bugs appearing inside during winter or early spring.

• Foul odor or staining from crushed bugs on walls, curtains, or furniture.

Prevention Tips

• Seal gaps around windows, doors, siding, vents, and foundation openings.

• Install tight-fitting screens and door sweeps to block entry.

• Remove nearby boxelder or seed-bearing maple trees if possible.

• Vacuum up indoor bugs—avoid crushing to prevent stains or odor.

When to Call a Professional