Summer Pests in the Greater Toronto Area

As temperatures across the Greater Toronto Area climb above 25°C and the humidity settles, summer brings the most intense pest activity of the year. Within the period of late June through August, several species will reach peak population from the combo of heat, moisture, and foods sources meaning any pest problem that starts in June will develop into a serious infestation by August if left untreated.

1. The Aggressive Nesters: Wasps and Yellow Jackets

While wasps appear in spring, wasp colonies reach their maximum size and aggression in the summer. A nest that started as a few dozen workers in May can grow rapidly to 5,000 to 10,000 workers by late August.

2. The Structural Threat: Carpenter Ants (Peak Activity)

Carpenter Ants reach peak foraging activity in June and July after emerging from their satellite colonies started in spring. Mature colonies (3+ years old) will start producing their first batch of winged ants (also known as alate) that emerge on warm humid days to start new ant colonies.

3. The Summer Surge: Cockroaches

The Greater Toronto Area's most common cockroach, the German Cockroach thrives in temperatures above 25°C. Their reproductive cycle accelerates significantly in summer heat and cockroach populations that takes two months to double at room temperature can double in under six weeks under these higher temperatures.

4. The Slow Hitchhikers: Bed Bugs

Summer is the peak season for bed bugs across the Greater Toronto Area. Hotel stays, short-term rentals, air travel, and even second-hand furniture left on the side of the road are their primary travel methods.

5. The Wildlife Peak: Raccoons with Their Young (Kit)

By June, kits born in April and May are mobile and beginning to forage alongside their mother. GTA raccoon families are at peak activity through August with juvenile raccoons exploring new territory account for most late-summer entering attics for shelter and foraging garbage bins/dumpsters for food.

Summer Pest Prevention Checklist for GTA Homeowners

1. Inspect eaves and overhangs weekly in June and July: Wasp nests start the size of a golf ball in June can be knocked down with a garden hose. By August, professional treatment is required as they have established their nest heavily increasing the number of workers.
2. Secure outdoor garbage bins: Use locking lids and rinse bins monthly. Wasps and raccoons are aggressively attracted to food waste in summer heat.
3. Check under sinks and behind appliances: Summer heat increases water condensation in these areas. A slow drip under the kitchen sink in July can sustain a cockroach colony through to fall.
4. Inspect luggage after any travel: Bed bugs are introduced almost exclusively through passive transport. Check all seams before bringing bags inside and launder clothes on high heat immediately. If you spot any bed bugs on your body, bed bugs can be washed off and killed with water.
5. Trim tree branches away from the roofline: Squirrels and raccoons use overhanging branches as a bridge to your roof. Regular trimming of nearby trees help maintain at least three metres of clearance from any branch to the structure.