The rest of Revelstoke's summer could still buzz with biters subject to weather, despite the region's mosquito contractor dropping more than four tonnes of larvicide, it shared in a report.
Setekwe Environmental Inc., a Barriere, B.C., company specializing in mosquito control that the Columbia Shuswap Regional District hires to mitigate bug activity in Area B, answered the City of Revelstoke's request for an update in a letter Thursday, July 17.
Biologist Cheryl Phippen wrote that Setekwe treats mosquito habitat with a bacteria that larvae ingest, but that doesn't harm other insects and animals, with technicians initially wading through the Columbia and Illecillewaet rivers' floodwaters to target nesting grounds.
"As the water rises in the Columbia floodplain, extensive habitat becomes activated with larvae and it becomes necessary to apply the larvicide by helicopter," Phippen said.
By last Thursday, Setekwe's technicians had made 467 site visits this year, treating 95 hectares of land in the Revelstoke area on foot. The company further sprayed 800 hectares by helicopter, releasing 4,308 kilograms of larvicide 鈥� the weight of about three Honda Civics 鈥� which Phippen said more than doubled its aerial treatment in 2024.
Despite more intensive application this year, and "very little mosquito annoyance" up until the Canada Day long weekend, she reported Setekwe has received many local complaints since the start of July. Floodwater mosquitoes often don't make it past two or three weeks when it's hot out, Phippen explained, but Revelstoke's lush greenery 鈥� "mosquito harbourage area" 鈥� helps expand their lifespans.
"As long as there are moist, cool areas for adult mosquitoes to avoid the sun during the day, they can continue to live for a few additional weeks, although their numbers will steadily decrease," she said. "It has been noted that mosquito annoyance is much greater in the morning and the evening, and this is to be expected as the adults are active when it is cooler."
Setekwe strongly recommends Revelstokians protect themselves with mosquito repellents that use DEET as their active ingredient, which are also effective at deterring ticks.
Ultimately, "the biggest challenge for this mosquito reduction program is the proximity of the City (of Revelstoke) to hundreds of hectares of habitat south of the airport," Phippen noted. "Depending on the year, billions of mosquitoes can emerge from this untreated habitat and depending on winds, many can reach the city."
Tight densities of hundreds of larvae can still persist within treated areas, even in just a 300-millilitre water cup, and millions of bugs will still emerge each year, "even with an exceptional mosquito control effort," she added.
Whether residents can look forward to some late-summer respite from these buzzing biters depends on the weather. For now, the good news is Setekwe isn't finding any more substantial larvae populations and has treated fewer than 10 hectares since early July, Phippen said
"We are expecting very little larval development, and therefore, the temperature will determine how long the annoyance will last," she added. "If Revelstoke gets some hot, dry weather, mosquito populations should decline rapidly."
