City needs new weapon in skeeter battle: report

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This article was published 22/11/2024 (303 days ago), so information in it may no longer be current.

The best option to battle Winnipeg’s mosquitoes is to find a new fogging product, city officials say.

The city currently fogs adult nuisance mosquitoes with DeltaGard, but has been studying options to replace the fogging agent after the company stopped selling it in Canada in 2023.

While the city has stocked enough of the product to cover two to three years of mosquito control, depending on weather, the issue led it to explore other options, a new report notes.

“Of all the options presented, the easiest to implement and least costly control method is to find a new adult mosquito control product. Failing this, the recommended course of action would be to invest in improving the larviciding program,” the report notes.

While another pesticide company plans to introduce a new adult mosquito control product within five years, which could replace DeltaGard, that hasn’t happened yet, the report adds.

Replacement product not yet available in Canada

In an interview Friday, the city’s superintendent of insect control said it’s difficult to determine how likely the city is to run out of the fogging product years before a replacement is available.

“I wouldn’t say it’s a high risk. We are also still trying to work with the supplier (of DeltaGard) to see if they would change their mind (about selling their product in Canada). We’re still looking at other options,” said David Wade.

Wade said the possible replacement product, which he did not name, is used in the United States but is not yet regulated for use in Canada.

“There is a risk, obviously, of running out and not having another option available, so that’s why we want to bring this information forward,” he said.

Wade noted the city could also stretch out its DeltaGard supply by raising the threshold to trigger a fogging operation, though that option hasn’t been approved.

Other options: larvicide changes, sterile males

The city could also ramp up larviciding resources or switch to longer-lasting larvicides and reduce mosquito larval development sites, among other options, the report notes.

“Potential alternatives to traditional mosquito control include introducing natural predators, a backyard mosquito trapping program, and releasing sterile males,” it states.

The report doesn’t recommend a specific action but notes council’s community services committee could order another report to cost out the options.

Longer lasting methoprene-based larvicides cost about three times more than a more basic option Winnipeg’s insect control branch uses in mosquito abatement zones beyond city limits, Wade said. However, the pricier option lasts 21 days, whereas others are only effective for a day or two.

Whether the more potent product pays off in fewer mosquitoes largely depends on how often it rains, he said.

No fogging option ‘makes me nervous’: councillor

The report notes Winnipeg has fogged adult nuisance mosquitoes on an as-required basis since 1950 and used DeltaGard as a less toxic option since 2017.

Coun. Vivian Santos, chairwoman of the community services committee, did not respond to a request for comment.

Coun. Evan Duncan, a former community services chairman, said he’s been impressed by how effective Winnipeg’s larviciding program is in warding off mosquitoes, especially in dry years.

However, Duncan said it’s important for the city to ensure it is never left without a fogging product.

“Going without any option for fogging makes me nervous… If we have a super wet season… where there’s no other option but to fog and we don’t have anything to fog with, that’s trouble,” he said.

The report lists options the committee could consider:

• Increase larviciding resources to inspect all known mosquito development sites within seven days, which would require a new mosquito control facility to accommodate more staff, vehicles and equipment.
• Expand the use of methoprene-based larvicides, which are effective over a longer period but are more expensive.
• Reduce the amount of mosquito larval development sites, such as by reducing standing water sites through drainage, which would require support from the province and rural municipalities. This could also include education for private landowners to reduce standing water.
• Introduce natural predators, such as adult dragonflies, certain birds, and bats, though that may not be cost effective.
• Add a backyard mosquito trap program, which could be subsidized, though this wouldn’t have much impact on parks and natural areas.
• Create sterile lab-grown insects to release into the environment and reduce numbers of viable eggs.
• Obtain a new fogging product.
• Explore novel control options developed by academics, including new “sterile insect techniques,” though this research is not expected to be ready for at least 10 years.

joyanne.pursaga@freepress.mb.ca

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