Edmonton to see spike in mosquitoes following period of heavy rain

The recent rain has allowed for a boom in the mosquito population, but it wasn't ideal for a particular species of mosquito that carries the West Nile virus.

With heavy rain soaking the capital region over the last few weeks, Edmontonians can expect to see more mosquitoes than were seen in the spring and compared to years past.

“So it’s filled up a lot of those temporary habitats where the mosquitoes have laid their eggs in previous seasons, activated those eggs, and we are seeing the results of the first wave have already started coming out,” said Mike Jenkins, biological sciences technician with the City of Edmonton.

However, with the last few summers being particularly dry, the egg population is less than it would be if those years saw the same precipitation levels as 2026.

“We’ve had five or six years of very low mosquito numbers, so there aren’t that many viable eggs actually out there,” said Jenkins. “So, for the level of water that we’ve got on the ground, the amount of hatching and the mosquitoes that are developing from that is actually remarkably low.”

But Edmontonians should be prepared to see more mosquitoes while outdoors, especially in the dawn and dusk hours.

How to deal with mosquitoes in your back yard

City crews are currently working on dispensing liquid larvicide to ditches, ravines, parks and school yards that have accumulated standing water.

But water that has amassed in backyards and private property is up to the property owners to deal with.

“They just can’t control all of the standing bodies of water, random puddles in backyards, drainage ditches that are plugged in the back alleyway, people’s bird feeders, things like that,” said Brian Webster of Buzz Boss.

Residential pest control companies are a viable solution, which typically spray a Health Canada approved pesticide to areas where mosquitoes lay their eggs.

Residents can also get rid of standing water by cleaning out bird baths regularly and emptying containers that have collected water.

Jenkins also recommends setting up an oscillating fan pointed away from you while outside to prevent mosquitoes from flying near you.

“They are more careful about how they’re selecting their targets so they take longer to actually settle down,” said Jenkins. “A variable breeze that blows across them makes it much less attractive for them to land on you.”

Breed of mosquitoes carrying West Nile seen in Edmonton

With the region seeing milder winters, a breed of mosquitoes known to carry the West Nile Virus have become more prominent.

Culex pipiens typically prefer warmer conditions and less rain and develop in very temporary habitats like eavesdrops, bird baths, discarded tires, rain barrels and storm water catch basins.

But with the amount of rain Edmonton has seen and will continue to see this weekend, culex pipiens aren’t likely to be as prevalent this season if precipitation persists.

“It is a potential concern because culex pipiens are the primary vector for West Nile Virus in North America … We’re monitoring the population, seeing what’s happening in terms of those populations,” said Jenkins.

The University of Calgary is looking to do a genetic testing of culex pipiens from across the province to track West Nile development, said Jenkins, adding that the city is sending the university materials for their study.

“A good point is the culex pipiens itself is what’s called ornithophilic, they prefer to go after birds as their host for blood meals … but they don’t seem to be biting people,” said Jenkins. “That’s a good sign that it’s not the subtype of culex pipiens that is aggressively going after people, but also reduces the potential risk of spillover for West Nile Virus transmission.”

The province said one case of the virus has been reported to Primary and Preventative Health Services but was acquired outside of Alberta.

With files from CTV News Edmonton’s Amanda Anderson