Boxelder Bug Control Calgary

Boxelder bugs are one of the most recognizable insects in Calgary, thanks to their distinctive black bodies marked with bright red-orange lines along the edges and wing veins. These bugs are native to North America and have become particularly abundant in Calgary because of the city's extensive planting of Manitoba maple trees — also known as boxelder maples — which are the bug's primary food source. The bugs feed on the tree's seeds, leaves, and flowers, and female (seed-bearing) trees attract the largest populations. In Calgary neighbourhoods like Inglewood, Bridgeland, Mount Royal, and Beltline where mature Manitoba maples line the streets, boxelder bug invasions are a yearly occurrence.

The problem for Calgary homeowners begins in early to mid-September when nighttime temperatures start dropping. Boxelder bugs sense the coming winter and begin searching for protected overwintering sites. They're drawn to the warm, sun-exposed south and west-facing walls of homes, where they cluster by the hundreds or thousands on sunny afternoons. From these staging areas, the bugs find their way indoors through every available gap: around windows and doors, through vents, under siding, and into attics. Once inside, they settle into wall voids and remain largely inactive until spring — but on warm winter days, many become active and emerge into living spaces, often clustering around windows where they're most noticeable.

While boxelder bugs don't cause structural damage or pose health risks, they're a significant nuisance pest. When disturbed or crushed, they release a pungent, staining liquid that can discolor curtains, walls, and flooring. Their droppings can stain surfaces, and large accumulations in light fixtures and window sills are unsightly. For Calgary homeowners dealing with annual invasions, professional treatment is the most effective solution. Calgary Pest Guard provides timed exterior perimeter treatments in late August and September that create a protective barrier, killing bugs before they enter. We also identify and recommend sealing of entry points to provide long-term protection. If bugs have already entered your home, our interior treatments target wall voids and harborage areas to eliminate the existing population.