Spring Pests in the Greater Toronto Area

As the snow melts and the ground thaws in the Greater Toronto Area (GTA), the city wakes up to a flurry of biological activity. In Southern Ontario, the transition from March to May marks a "peak season" for several pests that have spent the winter in a dormant state (diapause) or tucked away in the warmth of your home's walls.

1. The Home Invaders: Carpenter Ants

Unlike less common termites in the GTA, Carpenter Ants are the primary structural pest for Ontario homeowners. As temperatures consistently hit double digits, these ants begin foraging for water and sweets.

• The Warning Sign: Seeing large black ants inside your house in April is usually a sign of a "satellite colony" already established within your walls.
• The Risk: They don't eat wood but they make holes in it to build nests which can weaken structural beams over time.

2. The Early Bloomers: Boxelder Bugs and Western Conifer Seed Bugs

If you notice shield-shaped insects crawling on the sunny side of your brickwork or appearing suddenly on your curtains, you're likely dealing with "overwintering" pests.

• Boxelder Bugs: Identifiable by their black bodies with red or orange markings. Eastern boxelder bugs are a native species in North America. Boxelder bugs are harmless to people and pets.

• Western Conifer Seed Bugs: Often mistaken for "stink bugs" due to their appearance and the odour they release when crushed.

• The Behaviour: These insects spent the winter inside your attic or wall voids. When the spring sun warms the house, they think it is time to go outside but often end up crawling into your living space instead.

3. The Garden Raiders: Ticks

With the GTA seeing a steady rise in temperatures over the last few years, Black-legged Ticks (Deer Ticks) are becoming active much earlier in the spring.

• Where they hide: Tall grass and leaf litter in areas like the Don Valley, High Park, or the Rouge Valley.
• The Risk: They are active as soon as the temperature reaches 4°C. In the spring, they are often in their "nymph" stage—about the size of a poppy seed—making them very difficult to spot.

4. The Nuisance: Termites

While not as widespread as ants, certain pockets of the GTA (especially the East End, Danforth, and parts of North York) are known "termite zones." Spring is swarming season.

• The Swarm: On warm, humid days following a spring rain, winged "reproductives" emerge to start new colonies.

• How to tell them apart: People often mistake winged termites for flying ants. Termites have straight antennae and equal-length wings whereas ants have elbowed antennae and wings of different lengths.

Spring Pest Prevention Checklist for GTA Homeowners

To keep the "uninvited guests" at bay this season, consider these quick maintenance steps:

1. Clear the Gutters: Clogged gutters create the damp wood conditions that Carpenter Ants and termites love.
2. Inspect Windowsills: Check for gaps in screens or cracks in the caulking where boxelder bugs or spiders might enter.
3. Manage Mulch: Keep garden mulch at least 12 inches away from your home's foundation to prevent it from acting as a "pest highway".‍
4. Dry Out the Basement: Use a dehumidifier to reduce moisture as spring brings dampness which attracts silverfish and centipedes.