Saskatoon’s mosquito surge: How rain, heat and drought recovery created a bug boom

For many Saskatoon residents, this summer’s soundtrack has been the familiar buzz of an unwelcome visitor.

From backyard gatherings to evening walks, mosquitoes have become one of the defining features of the summer, leaving many people wondering why the city is seeing such a dramatic surge.

According to Saskatoon’s city entomologist Georgiana Antochi-Crihan, who joined Mark Loshack on the CKOM morning show, she said the answer lies in a perfect combination of rainfall, heat and a landscape recovering from years of drought.

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“It’s been one of the worst years in recent times,” Crihan said.

While the mosquito population has been unusually high, Crihan said the context behind the numbers is important.

“We’ve been in a bit of a drought right until recently,” she explained. “So, part of the averages we report for mosquitoes are a little bit influenced by that drought, but that doesn’t make it any less worse when mosquitoes are swarming you out there.”

Crihan said the return of moisture across the province has opened opportunities for them that weren’t available before.

“With mosquito management, it always comes back to rainfall and temperature,” she said. “Mosquitoes need water to reproduce because they have an aquatic larval life stage. Without water, they can’t make any more babies.”

Because Saskatchewan weather has swung from extreme to extreme, Crihan said conditions determine how quickly mosquitoes develop.

“If we get really hot days like we’ve been seeing lately, it can push up that development window from egg to adult to be about as short as a week,” Crihan said.

She said the result has been a noticeable spike in mosquito numbers across Saskatoon.

“We had about 168 mosquitoes per trap that we intercepted, and when you compare that to the 10-year average, that was about 12 mosquitoes we’d see in the traps for the 10-year average,” Crihan said.

“That’s significantly more.”

She said the city’s mosquito control program has been responding by monitoring breeding areas and treating locations where mosquito populations reach certain thresholds. Crews inspect known mosquito habitats in public spaces and within a two-kilometre buffer around the city.

According Crihan, the treatment used by the city contains Bacillus thuringiensis israelensis (Bti), which is a naturally occurring bacteria that targets mosquito larvae.

“It only affects mosquitoes and closely-related flies, and is perfectly safe to use around people, pets and wildlife,” she said.

For residents looking to reduce mosquitoes at home, Crihan said the most effective strategy starts with removing standing water.

“Water control is the name of the game in terms of mosquito management,” she said. That means checking places where water can collect, including plant trays, pet bowls, bird baths and even unexpected spots like tarps or containers left outside.

“If it gets a little bit of organic matter – say like leaves, algae, clippings, anything, mosquitoes will love that,” Crihan said.

While products like citronella candles and bug devices are popular, Crihan said “bug spray works wonders.”

As summer moves into August and September, the city will also continue monitoring for Culex mosquitoes, which can be deadly.

“In our area, all Culex mosquitoes have the potential to carry and transmit West Nile virus,” she said.

Crihan said residents can reduce their risk by using repellent, wearing protective clothing and avoiding peak mosquito activity times around dusk and dawn.

After a summer of relentless buzzing, Crihan said the biggest lesson is simple: controlling water is key.

“When we get a lot of water, that’s just creating a lot more habitat and a lot more spaces for them to reproduce,” she said.