Swarms of red and black bugs are trying to infiltrate Ontario homes this time of year

Although they usually fly under the radar throughout the summer months, chances are you’ll encounter masses of red and black bugs in your backyard this fall if you’re a homeowner in southern Ontario. 

Boxelder bugs (Boisea trivittata) are nuisance pests that often cluster in large numbers during the fall when they leave trees, shrubs, and other plants they normally live, feed, and reproduce on to find warm hiding spots for the winter. 

During their search, the insects often congregate in the sunshine on the south side of buildings, trees, and rocks to bask in the sunshine. From there, they often stray into homes through cracks in the foundation and siding, gaps along windows and doors, and any other small openings. 

The unwelcome pests can be distinguished by their almond-shaped bodies, which are black with red edges and roughly two centimetres long. 

Found 2 of these on my balcony

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As soon as the summer season comes to a wrap, pictures of boxelder bugs almost always appear on social media, as homeowners across the province look to others to identify the bug. 

Although the sudden emergence of the bug clusters on your property may be alarming, the good news is that the pests don’t usually bite humans or cause any serious damage to your home with their chewing. 

If you come across a cluster of these bugs, it’s not advisable to squish them, as their guts are rather stinky and can potentially leave permanent red stains on light-coloured walls or fabric. 

The best way to prevent the bugs from taking over your property or potentially invading your home is to repair holes in damaged window or door screens, install door sweeps on exterior doors, or use a good quality silicone to seal exterior cracks, crevices, and gaps around windows, doors, siding, roof joints, and areas where utility pipes or plumping enter your home. 

If you’re committed to removing these uninvited guests from your home yourself, you can either vacuum them up or gently sweep them outside.