Mosquitos and West Nile Virus
Each summer, mosquito larvicide is dropped into roadside catch basins, targeting the standing-water spots where mosquitoes typically breed. The goal is to help minimize the mosquito population and prevent the spread of West Nile Virus. For optimal efficiency, the product is distributed by people riding from basin to basin on bicycles or scooters.
The larvicide used is in a pellet or tablet form, and requires three treatments a few weeks apart. The substance used is not a poison, rather it interrupts the mosquitos' growth cycle so they do not become adults. It degrades rapidly in water so it does not accumulate in the environment. According to Health Canada, in the small amounts used, studies have shown it's safe for humans and animals.