If it seems like you’re slapping more mosquitoes in Winnipeg right now, it’s not just in your head.
The number of adult mosquitoes in the city has soared over the past week, mainly because high winds have stymied the city’s efforts to control the bloodsuckers.
Sustained high winds have blown large numbers of adult mosquitoes into the city from bedroom communities, said Ken Nawolsky, superintendent of Winnipeg’s insect control branch.
On Monday, the city-wide average mosquito trap count was 71, up from 18 on Friday and four the previous week.
“What we’ve been finding is that we have been doing a pretty good job in larviciding, but we’re getting some migration, from the strong winds, of mosquitoes that are coming from the capital region,” Nawolsky said Monday in an interview.
His staff bases this conclusion on the mix of mosquito species showing up in traps. Some are urban mosquitoes known to breed in standing water or in containers, but others are only known to mature in wetlands. Four genera of mosquitoes — Aedes, Culex, Culiseta and Coquillettidia — make up most of the bloodsuckers caught in city traps.
Nawolsky said mosquitoes can travel as far as 20 kilometres a day when they’re propelled by high winds.
Those same winds have also grounded insect control branch helicopters, preventing them from applying larvicides to standing water. About 80 per cent of the larviciding program is conducted by air, with ground crews conducting the rest of the work.
Nawolsky said those numbers will climb even higher if insect control helicopters are unable to fly over the next two days. A large cohort of mosquito larvae are almost ready to take to the air, he said.
“We’re just hoping we get a period of time before it’s too late,” he said. “They’re already getting ready to emerge as adults, so time is of the essence.”
Insect control branch helicopters cannot fly in winds above 20 kilometres an hour. Winds higher than that make it impossible to target bodies of standing water.
Nawolsky said the helicopters have been grounded nine days out of 10 because of unusually strong winds this spring. During a normal spring, they’re only grounded 50 per cent of the time, he said.
“It seems to be that we’re lucky to get in one day a week,” Nawolsky said.
Weather data backs him up: This is already the windiest June in Winnipeg in 30 years, CBC meteorologist John Sauder said.
Right now, temperatures in Winnipeg are high enough for mosquitoes to mature from hatchlings to adults in as little as six days, Nawolsky said. The larvicides methoprene and BTI are used to prevent them from maturing.
If the city-wide average trap count exceeds 25 for two straight days and one quadrant of the city has an average count over 100, the city could begin fogging for adult mosquitoes using the chemical deltamethrin.
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World news – CA – High winds boost Winnipeg mosquito counts and keep larvicide helicopters grounded | CBC News