Increase in Mosquito Population in Winnipeg Attributed to Wet May Weather
Winnipeg’s notorious bloodsuckers are on the rise due to a wet and rainy May, with some parts of the city experiencing more severe infestations than others.
“They have come out and are very active right now,” said David Wade, entomologist and superintendent of the insect control branch, during an interview with CBC Up to Speed host Faith Fundal on Monday.
Wade mentioned that city workers are finding an increased number of mosquitoes in their latest surveys. This surge is unsurprising given the significant rainfall in May, which creates ideal breeding conditions for mosquitoes.
As of Friday, the city’s insect control branch has set its Adulticiding Factor Analysis (AFA) level at “medium,” indicating moderate mosquito activity based on various factors, including trap count averages and rainfall.
To justify mosquito fogging, several criteria must be met, including an AFA level of “high” and mosquito trap count averages of 25 or more for at least two consecutive days. On Monday, the citywide trap count average was 25.
Another trigger for fogging is if a quarter of the city’s trap counts average 100 or more mosquitoes, Wade explained.
Fogging targets adult mosquitoes already on the wing, but most of the city’s mosquito management program focuses on larviciding. This involves treating standing water with a mixture that kills larval-stage mosquitoes before they can fly, Wade said.
Wade mentioned that approximately 80-85 percent of larvicide application in the city is conducted by helicopter. However, recent conditions with strong winds have sometimes complicated this process.
Currently, trap counts are higher in certain areas, such as North Kildonan and Charleswood, where the averages were 110 and 72, respectively, as of Monday. This is not necessarily abnormal, Wade explained.
For instance, Charleswood has many low-lying areas and roadside ditches, which do not drain as quickly as other parts of the city, he said.
Wade indicated that it is too early to predict how significant the mosquito nuisance might become later in the summer, though long-term forecasts suggest a drier summer with periodic rainfall events.
He advises homeowners to help mitigate mosquito populations by draining any standing water on their properties or treating those areas with insecticide. Additionally, he recommends covering rain barrels, regularly changing bird bath water, and clearing out eavestroughs to prevent water from getting trapped.
