City's annual mosquito fight takes full flight

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This article was published 20/5/2015 (2322 days ago), so information in it may no longer be current.

HEAVY precipitation over the long weekend has created the perfect breeding ground for mosquitoes, says the city's bug man, Ken Nawolsky.

The newly hatched mosquitoes are expected to appear in the next seven to 10 days, particularly in the Assiniboia and Charleswood areas.

With the forecast looking sunny and rain-free for the next week, the city is hopeful it can manage the number that become adult mosquitoes.

"This is a very significant rainfall that we had," the superintendent of insect control said Tuesday. (Environment Canada reported 36.4 millimetres fell on Winnipeg Saturday through Monday.)

"So we are putting all of our resources into this, our crews are working 16-hour days, our helicopters are flying."

Nawolsky said the city's spring larviciding program was successful, with the latest traps on May 15 showing a city-wide average of zero, and even until Thursday, there were only small pockets of mosquito hatchings.

"What happened on the weekend, with that additional rainfall, triggered more eggs to hatch, so we have a very significant emergence," he said, adding 180 staff members are monitoring the situation and treating about 74,000 acres of land where larvae could be developing.

Currently, city crews are using a biological larvicide known as Bti in standing water (which kills larvae within 36 hours) along with methoprene, a longer-lasting, slow-acting insecticide.

Residents in Charleswood and Assiniboia are especially encouraged to remove any standing water that has been on their property for more than seven days.

If required, the city will continue to be use malathion this summer, despite a statement by the World Health Organization that it is possibly carcinogenic. Nawolsky noted the federal government has approved its use and Manitoba Conservation has issued the city a permit.

However, buffer zones will remain in use and residents can find out how to register as "anti-pesticide registrants" for both forest tent caterpillar and mosquito-control programs by calling 311.

After concerns were raised last month the city was running out of malathion, Nawolsky reaffirmed a local firm has been found to keep the city supplied throughout the summer.

The city is hoping to test alternatives to malathion but it would take more than 18 months to bring any successor into larger-scale use.

Taz Stuart, the city's former bug man and now director of technical operations for Poulin's Pest Control Services, says it always comes down to two factors when predicting how many mosquitoes Winnipeg will face: rainfall and temperature.

"A lot of rainfall, a rainfall event of more than an inch usually produces reasonable conditions," he said. "A lot of those sites that are dried up after the winter now would potentially be seeing an egg hatch and larvae developing -- and as it gets warmer it goes faster."

kristin.annable@freepress.mb.ca