July 15th, 2019

Weather giving City leg up in battle against mosquitoes


By Mabell, Dave on July 12, 2019.

Mosquito technicians Keisha Eagle Plume and Ron Esau check for larvae in standing water along a roadside ditch Thursday morning near the south edge of the city. Herald photo by Ian Martens @IMartensHerald

Dave Mabell

Lethbridge Herald

dmabell@lethbridgeherald.com

Canada Day was the big test. With thousands of people enjoying the day in Lethbridge parks, how many would be bitten?

“We received no complaints,” reports Ron Esau, the City of Lethbridge’s mosquito expert.

“It could be the worst time of year.”

But southern Albertans should still protect themselves from mosquito bites, he cautions, because local mosquitoes may still be carrying the West Nile virus.

While people in Calgary and Edmonton have been swatting the bugs as usual, Esau says Lethbridge-area residents have been fortunate. We haven’t been hit by the same downpours that have been reported farther north – even though forecasts warned we would.

Moderate rainfall in May and June soaked into southern Alberta soil, he explains, while heavier precipitation could have created the puddles and pools that nurture mosquito larvae.

“It’s a really positive situation,” Esau says.

And his small parks department team aims at keeping it that way. It continues to monitor ponds and low spots around the city, armed with a bacterial control agent that prevents the larvae from hatching.

“We want to keep Lethbridge mosquito-free.”

That’s a tall order, and Esau remembers some recent years when Canada Day celebrants were not so lucky.

Storms in June, followed by hot days late in the month, created favourable conditions for hatching.

“It was ‘the perfect storm’,” he says. “So it was terrible.”

That scenario earlier in the season can cause even greater problems, he points out. Female mosquitoes – nourished by human blood – can lay a batch of 200 eggs every two weeks. Then the next-generation females do the same, and numbers multiply.

Around Lethbridge, that didn’t happen this year. And although thunderstorm warnings have been issued frequently, the city has received just a little rain. And it’s been very localized, Esau notes, with some parts of the city remaining dry.

“Things are looking pretty good,” he says.

But residents should still take precautions, especially in the evening.

That’s when females in the culex tarsalis variety come calling, he explains. They’re the ones that carry the danger of West Nile Virus, which can cause serious illness or death.

“They’re voracious eaters,” with just their bite alone causing distress.

“People should not start thinking that they’re safe.”

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