The City of Edmonton is ending aerial-spraying to control mosquitos, in favour of natural alternatives such as using mosquito-eating dragonflies and bats.Ian Jackson/The Globe and Mail
Ahead of mosquito season this summer, Edmonton is permanently ending its aerial-spraying control program in favour of natural methods to manage the pest population.
At a meeting on April 4, Edmonton City Council voted 9-4 to reallocate the $507,000 budget for the aerial program to techniques such as the use of mosquito-eating predators, including dragonflies and bats.
The aerial program, which used low-flying helicopters to spray larvicide on pooling water on the outskirts of the city, has been the subject of debate for the past two years owing to environmental and financial concerns.
“We’re not stopping treating mosquitoes, but we are also going to be working on bridging to more sustainable, nature-based solutions which in the long term will help save all of us money,” said Councillor Michael Janz, who brought forward the motion to prioritize natural methods.
The Decibel: How Edmonton hopes to get mosquitos to buzz off
Across the country, municipalities are struggling to strike the right balance between tightening their budgets and limiting the use of pesticides for environmental reasons, while also responding to demands from residents to control mosquitoes and the nuisance they cause.
At the recent meeting, several Edmonton councillors expressed reservations about cutting the aerial program too abruptly, arguing that the city staff should be given more time to develop a robust alternative plan.
Mr. Janz and other councillors who pushed to end the aerial program questioned its effectiveness. When city staff were asked about metrics at the council meeting, they pointed to resident feedback and the relative increase or decrease of complaints being logged to measure program efficacy.
“It is not financially sustainable, let alone environmentally sustainable, to keep doing the same thing year after year, with no real metrics,” Mr. Janz said.
The plan moving forward this summer includes using permaculture and landscaping techniques to modify potential breeding sites, working with the Alberta Community Bat Program to install and monitor an additional 50 bat boxes, and developing habitats to allow dragonflies to flourish. The city also proposes to invest in enhanced collection and data analysis tools to better measure and evaluate mosquito population dynamics.
Local conservation and health groups have been calling on the city to stop using pesticides altogether, citing negative human-health risks and effects as well as the threats chemicals pose to the local wildlife and ecology.
Sean Prager, who leads the University of Saskatchewan’s newly funded Insect Research Centre, said that while mosquitoes are a nuisance, they are also a vital part of the ecosystem. The insects are a food source and a pollinator, and he argues that spraying is not a solution.
“Just because they are annoying doesn’t meant they don’t serve other purposes or have other roles,” Dr. Prager said in an interview. “This country has insects, and rural environments can’t be antiseptic so that cities don’t have mosquitoes.”
He said the natural methods proposed by the city will help keep mosquito counts low, but nothing will ever eliminate them.
Dr. Prager also argues that if Edmonton residents want relief from mosquito bites, they also have a role to play themselves.
“The local solution of removing standing water in your yard, wearing protective clothing or bug spray is going to be significantly more effective in the long term.”
Edmonton City Council previously voted in the fall of 2020 to eliminate the $507,000 budget for the aerial-spraying program as part of a series of deep cuts in every city department to keep property taxes frozen. The cuts didn’t affect ground-based mosquito mitigation measures, including application of larvicide in ditches and other local breeding-ground areas, which is budgeted at $650,000 per year.
Council reversed course in the spring of 2021 in response to outcry from local residents who, after being stuck inside because of pandemic protocols, wanted to be able to enjoy the outdoors bug-free. One-time funding was approved for that season.
During budget deliberations in the fall of 2021, council voted to restore funding to the pest-management program, while opting to hold off allocating the money to aerial spraying until city staff delivered a report to committee with their plan for 2022, including details surrounding the method. That report was delivered in March.
The budget of $507,000 for aerial spraying in the staff report was based on the price of fuel and materials in 2020 for three or four applications per season. According to the report, the budget would only be enough for two of the four recommended aerial applications in 2022.
In previous years, the actual cost of the program has also changed throughout the season with little to no warning, as mosquito population is driven by the amount of rain and stranding water.
In 2020, which was an extremely wet season, city staff appealed for more money to cover four extra treatments, amounting to eight in total. That year, the aerial program cost the city $905,000.
In 2021, the driest season on record because of extreme heat across Western Canada, the city only used the aerial program once at a cost of $497,000.
Investing in natural predator solutions is a step in the right direction, according to Mr. Janz, and creates opportunities for local community leagues to “get active in our own rescue,” and support the efforts of city staff.
And before Edmontonians start to panic, Philip Herritt, director of infrastructure operation for the city, reassures residents that city staff have a rigorous pest-management control program that is already at work this season.
“The city’s existing robust and targeted ditch and ground mosquito programs target roadside ditches and other ground habitats in our control area where mosquito larvae will be developing,” he said.
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