Edmonton has received nearly 200 millimetres of rain in June, raising expectations of a severe mosquito season. However, Mike Jenkins, the city's biological sciences technician in charge of pest control, says that several years of drier conditions have reduced the number of dormant mosquito eggs. Despite abundant standing water from rainfall, the typical surge of floodwater mosquitoes has not yet occurred.
New Mosquito Species Arrives in Edmonton
But a new threat is emerging. The mosquito species Culex pipiens is finally migrating to Alberta. This mosquito is associated with West Nile virus, and Jenkins says it likely caused the deaths of two grey owls at the Calgary Zoo in 2025. Unlike the predominant Aedes and Ochlerotatus groups found in Edmonton, Culex pipiens does not rely on floodwater.
“Unlike the floodwater species that rely on that rainfall filling up those temporary vegetated habitats, (Culex pipiens) are species that lay rafts of eggs on top of very temporary water bodies that don’t need vegetation at all, so their eggs aren’t sitting dormant,” said Jenkins. “These are ones where the mosquito comes in very quickly, lays eggs, and those eggs hatch almost immediately, and so their population can ramp up fairly quickly.”
How to Make Your Yard Less Attractive to Mosquitoes
Jenkins explained that Culex pipiens thrives in backyard habitats. Common breeding sites include clogged eavestroughs, rain barrels, birdbaths that are not regularly emptied, and fish ponds. To reduce mosquito larvae, homeowners should take simple steps.
“It (changing the birdbath water) is going to keep the mosquito larvae from being able to develop in there,” said Jenkins. “If you’ve got a rain barrel, putting a screen over top of that to keep the mosquitoes out, so they can’t lay eggs on the surface of the water, is going to help reduce those populations while you’re in your backyard itself.”
Use Fans to Keep Mosquitoes Away
For those spending time on their deck, a simple fan can be an effective defence. Mosquitoes cannot bite or land if they cannot fight the airflow.
“An oscillating fan that blows across the porch can keep mosquitoes from hanging out underneath patio furniture and, while you’re sitting out there, can actually keep them from landing or trying to bite you,” said Jenkins.
Highway Ditches: Perfect Mosquito Habitats
Because Culex pipiens eggs hatch almost immediately, any standing water can become a breeding ground. Highway ditches are particularly attractive because predators like birds avoid areas near moving vehicles where there is no perch. These ditches collect water and offer shelter, inadvertently creating ideal mosquito habitats.
