Mosquito larvae are showing up in higher concentrations this year than they did in this 2017 sample. Western News file photo

Floods create ideal breeding grounds for mosquitoes

After the floods, pestilence

You can add mosquitoes to the long list of problems caused by the flooding the South Okanagan has suffered over the last month.

Standing water, like the pools left over from the floodwater, is an ideal environment for the larval stages of the mosquito’s lifestyle.

“During this flood time we are being inundated, as we were last year with folks that are asking us to come and look at their properties, and if they meet the criteria, to treat them,” said Zoe Kirk, who oversees the RDOS pest management program.

“We definitely have ramped up our program a lot. Last year was a learning year because we had lots of flooding from the lake. This year a lot of our waterways, rivers and creeks, were adding to the mix and pooling in people’s yards and orchards and such.”

Related: Mosquito control sucks up budget

Not only are there more places to treat, Kirk said the number of larvae has increased. Mosquito eggs, she explained, can last for up to a decade until conditions are right to hatch into larvae.

Crews in the filed have to assess locations before they apply the bacterial larvicide, using a dipping tool to see how many larvae they collect. Kirk said if there are more than three in a dip, they can proceed.

“We haven’t had to worry this year, because most of the time, when they dip, it comes up and its black,” said Kirk, adding there were so many larvae in one of the samples the crew brought back to her from the Willowbrook area that she could hardly see through the glass.

The sample also contained a surprise. This time of year, the larvae are for the Aëdes Vexans mosquito — “Those big, fat mosquitoes that love people,” Kirk said.

But the sample also contained Culex mosquito larvae, which usually appear in August.

“It’s a much smaller mosquito, and it doesn’t really like people, but it is the West Nile carrier,” said Kirk. “To have them come out early must have been because of that extreme amount of heat we had and the flooding.”

Related: Simple steps for mosquito safety

Kirk said it’s a significant find, though it may not mean as much to the public since we’re not on the Culex’s regular diet.

“Things are changing. If we get this heat early and there is water on the ground, we may get more than one variety of mosquito,” said Kirk. That can change management plans — here are more than 50 varieties of mosquitoes in the area, including one that isn’t affected by the bacteria.

The larvicide is very effective though. Kirk said she dropped just two grains of it into the Willowbrook sample, and the larvae were all dead within three hours — except one that managed to hatch and she then had to hunt down.

BTI is a naturally occurring bacteria, Kirk said, which is mixed with the ground up remains of corn stalks. it spreads through the water

“Until you get to a certain density the same amount of bacterial larvicide is going to work,” said Kirk. “They (mosquito larvae) pull it in.

“It is exceedingly effective. We have gone through more larvicide because there are just simply more sites.”

Research has shown the larvicide is harmless to humans and other animals, but Kirk said they are still exceedingly careful.

‘We do not treat (nature) conservancies, we do not treat any water that is moving toward a creek, a river or the lake,” said Kirk. “It has to be landlocked.”

The mosquito control crew has been working 10-12 hour days trying to keep up, Kirk said, adding they also use a helicopter to spread the larvicide.

“We will probably be flying the helicopter a more because there are areas that it is just not effective to treat by hand,” Kirk said.


Steve Kidd
Senior reporter, Penticton Western News
Email me or message me on Facebook
Follow us on Facebook | Twitter | Instagram

Just Posted

B.C. premier says Greyhound replacement news could come shortly

Province is working with the private sector to find a solution, says premier

Okanagan-Shuswap weather: mix of sun and clouds

Environment Canada is calling for a chance of rain and risk of thunderstorms across the Okanagan tonight

Mellalieu running for Greens again in Central-Okanagan-Similkameen-Nicola

Robert Mellalieu ran for federal Green Party in 2015 election and provincial Greens in 2017

Memorials set up to honour Antarctica explorer

In 1913, two memorials in Summerland honoured Naval Officer Robert Scott

Multiple crashes slow traffic on Coquihalla south of Kamloops

Drivers are expected to be stuck for up to 90 minutes

VIDEO: Tributes flow on 10th anniversary of Michael Jackson’s death

Jackson received a fatal dose of the anesthetic propofol on June 25, 2009. He died at age 50

VIDEO: Killer whale steals fisherman’s catch off North Coast

Fishing duel results in eager orca snagging salmon in Prince Rupert

Big changes to food services at UBC Okanagan

Healthy, high-quality food on the menu as UBCO staffs up for in-house operations

Tolko donation helps build new Okanagan daycare

The Early Years Daycare Centre is scheduled to open at the end of summer 2019

COSAR rescues hiker from Okanagan Mountain Park

The woman hurt her ankle and was unable to walk out without the help of the team

40 cats, kittens surrendered in apparent animal hoarding at Vancouver home

Officers found the cats living among piles of garbage and feces, suffering from fleas

Collision closes Highway 1 west of Salmon Arm

A motor-vehicle accident has closed Highway 1 in both directions west of… Continue reading

Vancouver Aquarium drops cetacean ban lawsuit in new lease agreement

Ocean Wise CEO Lasse Gustavsson called the updated lease an exciting new chapter for the aquarium

New river channel shuttle service in the South Okanagan

Company launches this Friday and offers services within City of Penticton limits

Most Read