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

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

gdffdg
Mission’s Fraser Valley Music Award winners credit hometown with fostering musical talent

Rebecca Sichon won the pop-category award; Roads Unknown took home the roots-category award

BCCDC photo.
16 school exposures in Abbotsford schools in 2 weeks

Fraser Health’s list grows by 11 for 2nd week of 2021

Ron Restrick lives with mild cognitive impairment, but has worked to stay active and engaged in his community.
Abbotsford residents invited to Alzheimer Society webinar

Session on Wednesday, Jan. 27 looks at dementia and long-term care

The route of the pink parade. The Record has blackened out the name of the teen. Facebook photo.
Pink-vehicle parade to be held Sunday in support of transgender teen assaulted in Mission

Teen and family to watch parade drive single file along waterfront at 3 p.m., Jan. 17

The Anti-Racist Coalition Vancouver started a petition calling on B.C.’s education officials to make Black Shirt Day official. The inaugural event in solidarity with Black and racialized Canadians takes place on Friday, Jan. 15. (Screenshot/Change.org)
Mission School District holding first-ever Black Shirt Day in support of anti-racism on Friday

Growing calls to designate Jan. 15 a day devoted to ongoing civil rights struggle

Keith the curious kitten is seen on Nov. 4, 2020 at the Chilliwack SPCA. Friday, Jan. 22, 2021 is Answer Your Cat’s Questions Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of Jan. 17 to 23

Answer Your Cat’s Questions Day, Pie Day and International Sweatpants Day are all coming up this week

(Photo by Kevin Hill)
40 cases linked to Surrey Memorial Hospital COVID-19 outbreak

Fraser Health says two death are associated with the outbreak

JaHyung Lee, “Canada’s oldest senior” at 110 years old, received his first dose of the COVID-19 vaccine on Thursday, Jan. 14, 2021. He lives at Amenida Seniors Community in Newton. (Submitted photo: Amenida Seniors Community)
A unique-looking deer has been visiting a Nanoose Bay property with its mother. (Frieda Van der Ree photo)
A deer with 3 ears? Unique animal routinely visits B.C. property

Experts say interesting look may be result of an injury rather than an odd birth defect

Sooke’s Jim Bottomley is among a handful of futurists based in Canada. “I want to help people understand the future of humanity.” (Aaron Guillen - Sooke News Mirror)
No crystal ball: B.C. man reveals how he makes his living predicting the future

63-year-old has worked analytical magic for politicians, car brands, and cosmetic companies

Terry David Mulligan. (Submitted photo)
Podcast: Interview with longtime actor/broadcaster and B.C. resident Terry David Mulligan

Podcast: Talk includes TDM’s RCMP career, radio, TV, wine, Janis Joplin and much more

Seasonal influenza vaccine is administered starting each fall in B.C. and around the world. (Langley Advance Times)
After 30,000 tests, influenza virually nowhere to be found in B.C.

COVID-19 precautions have eliminated seasonal infection

Prime Minister Justin Trudeau listens to a question during a news conference outside Rideau cottage in Ottawa, Friday, January 8, 2021. THE CANADIAN PRESS/Adrian Wyld
Trudeau says Canada’s COVID vaccine plan on track despite Pfizer cutting back deliveries

Canadian officials say country will still likely receive four million doses by the end of March

Jobs Minister Ravi Kahlon shared a handwritten note his son received on Jan. 13, 2021. (Ravi Kahlon/Twitter)
Proud dad moment: B.C. minister’s son, 10, receives handwritten note for act of kindness

North Delta MLA took to Twitter to share a letter his son received from a new kid at school

Most Read