COVID-19 may have indirectly boosted mosquito numbers in one Fraser Valley neighbourhood. (Pixabay photo/File photo)

COVID-19 may have contributed to bad Fraser Valley mosquito season

Restrictions on helicopter occupancy may have resulted in less effective pesticide treatments

The COVID-19 pandemic may have played a role in making 2020 a particularly bad year for mosquitoes.

Weather and river conditions were the chief drivers of one of the worst mosquito seasons in recent memory. But occupancy limits in the helicopters that apply apply pesticides to mosquito breeding grounds may also have left some of the blood-sucking pests’ prime habitats under-treated.

A report to the Fraser Valley Regional District, notes that the season was shaping up fairly normally through June 5, when the river initially peaked. But instead of slowly receding over the summer, river levels dipped, then started to rise again, peaking once again on June 30 – above the level of the first peak.

Every year, the FVRD hires a private company to apply larvae treatments to mosquito breeding grounds along the river. In 2019, those wrapped up on June 21. But in 2020, the persistently high water required mosquitoes kept hatching through August. The last treatments were applied on August 17.

RELATED: Mosquito sites being monitored and mapped across the Fraser Valley

In all, just shy of 20 tonnes of one pesticide agent were used by Morrow BioScience, the company tasked with treating and eliminating mosquitoes. (The pesticides aren’t sprayed; rather a larvicide that the FVRD says is environmentally friendly is applied in granular or liquid form. The mosquito larvae ingest a toxic protein that kills them.) Even in 2012, another bad mosquito year, 14,489 kg were applied – 30 per cent less than this year’s total.

Each application of the pesticide kills about 90 per cent of larvae. But there were just too many mosquitoes in 2020.

“Based on the extremely high larvae abundance in 2020,” the FVRD report says, “despite the intensive treatment effort, the remaining 5-15% of surviving larvae that hatched into adults were enough to cause unfortunate annoyance in many lowland areas near the Fraser River.”

Last year, only four people called a mosquito hotline on which people can report the pests. This year, 130 calls were received. Of those, the vast majority – 99 – were from Chilliwack residents. And most of those were from Fairfield Island, the residential area of Chilliwack closest to the Fraser River and surrounded by sloughs.

The mosquitoes on Fairfield Island could be an indirect result of the COVID-19 pandemic.

Helicopter and boat crews were limited due to COVID-19 safety protocols. And while the report by FVRD staff said “these limitations are not believed to have significantly impacted the treatment efficacy,” a separate Morrow BioScience report suggested some potential effect.

“It is possible that sites were not treated as thoroughly as usual,” Morrow BioScience report said. “The high number of concern calls associated with Fairfield Island [in Chilliwack] indicate the possibility that sites on that island may have been over-looked.”

Do you have something to add to this story, or something else we should report on? Email:
tolsen@abbynews.com


Contact the reporter on Twitter at
@ty_olsen

Just Posted

FVRD surveyed public opinion on cannabis production and processing in the electoral areas. Odour and distance from residential areas were the top concerns. (Black Press file)
Cannabis production and processing rules being drafted by Fraser Valley Regional District

Data from public opinion survey will be used to guide cannabis-related land use

Robert Nelson, 35, died after being stabbed at a homeless camp in Abbotsford on April 7 of this year.
Mom pleads for information about son’s killing at Abbotsford homeless camp

Robert Nelson, 35, described as ‘man who stood for justice, honour, respect’

Police arrest the suspect in an attempted armed bank robbery on June 2 at the Scotiabank at Gladwin Road and South Fraser Way in Abbotsford. (Photo by Garry Amyot)
Abbotsford bank robbery suspect who was stopped by customers faces more charges

Neil Simpson now faces total of eight charges, up from the initial two

poster
Drop-in Covid vaccine clinic in Mission June 17-18

Neighbourhood clinics complement appointment-based clinics currently operating in Mission

Logo
Canadian Blood Service is adding additional donor clinics in Mission

New Sunday clinics begin June 20, donors can register online

Canadian Prime Minister Justin Trudeau participates in a plenary session at the G7 Summit in Carbis Bay, England on Friday June 11, 2021. THE CANADIAN PRESS/Adrian Wyld
Canada donating 13M surplus COVID-19 vaccine doses to poor countries

Trudeau says the government will pay for 87 million shots to be distributed to poor countries

Kelowna-Lake Country MLA Norm Letnick, assistant deputy speaker at the B.C. legislature, presides over committee discussions. The legislature is completing its delayed spring session this week, with most MLAs participating by video conference. (Hansard TV)
B.C.’s daily COVID-19 infections dip below 100 over weekend

Only 68 new cases recorded Monday, four additional deaths

The BC Ferries website went down for a short while Monday morning following a provincial announcement that recreational travel between health authorities can resume Tuesday. (Black Press Media file photo)
BC Ferries’ website crashes in wake of provincial reopening announcement

Website back up now, recreational travel between health regions to resume as of Tuesday

The Kamloops Indian Residential School is photographed using a drone in Kamloops, B.C., Monday, June, 14, 2021. The remains of 215 children were discovered buried near the former school earlier this month. THE CANADIAN PRESS/Jonathan Hayward
Communities grapple with what to do with former residential and day schools

Some tear them down as a tool to help healing, others repurpose them as tools for moving forward

FILE – Provincial health officer Dr. Bonnie Henry talks about B.C.’s plan to restart the province during a press conference at Legislature in Victoria, Tuesday, May 25, 2021. THE CANADIAN PRESS/Chad Hipolito
B.C. watching U.K.’s COVID struggles but don’t think province will see similar pitfalls

Studies show that one dose of vaccine is only 33 per cent effective in preventing B.1.617.2 spread

RCMP Const. Shelby Patton is shown in this undated handout photo. RCMP say that Patton was hit by an allegedly stolen truck that he had pulled over on Saturday morning in Wolseley, east of Regina. THE CANADIAN PRESS/HO, RCMP
Pair charged in Saskatchewan Mountie’s death make first court appearance

Const. Shelby Patton was hit by an allegedly stolen truck that he had pulled over Saturday morning

David and Collet Stephan leave for a break during an appeal hearing in Calgary on Thursday, March 9, 2017. THE CANADIAN PRESS/Todd Korol
Appeal Court rejects stay for Alberta couple facing third trial in son’s death

Pair accused in their earlier trials of not seeking medical attention for their son sooner

Highway notices like this come down effective June 14. Public health restrictions on non-essential travel and commercial operation have hit local businesses in every corner of B.C. (B.C. government)
Province-wide travel back on in B.C.’s COVID-19 restart plan

Gathering changes include up to 50 people for outdoor events

Calgary Stampeders’ Jerome Messam leaps over a tackle during second half CFL western semifinal football action in Calgary, Sunday, Nov. 15, 2015.THE CANADIAN PRESS/Jeff McIntosh
CFL football will be played this summer in Canada

Governors vote unanimously in favour to start the ‘21 campaign on Aug. 5

Most Read