Surrey man joins fight against invasive knotweed plant

Research looks at pesky plant’s ability to build up resistance to herbicide.

Surrey scientist Matthew Strelau stands in front of a knotweed outbreak on 60th Avenue in South Surrey. Strelau

Knotweed will not take over British Columbia if Matthew Strelau has anything to say about it.

The Surrey resident is studying whether the invasive bohemian knotweed plant will build up a resistance to the herbicide used to treat it.

Strelau is doing a month-long research project thanks to a $2,000 grant from the Weed Science Society of America.

Across the province, knotweed is treated with the chemical glyphosate, in the brand of weedkiller Round-Up, Strelau explained.

“You can apply it to so many plants, it breaks down easily in the soil, it’s cheap, it’s effective, but when you have only one herbicide you’re applying to one plant throughout the whole province, and this chance of resistance significantly increases,” said Strelau, who attends Trinity Western University.

The concern about resistance building is prudent, he explained, because of a hybrid that’s produced.

“There used to be giant knotweed and we had Japanese knotweed, but the issue now is the two hybridized together,” said Strelau. “Japanese knotweed was growing in local sites, it just couldn’t reproduce sexually, it couldn’t produce seeds, so it couldn’t travel far distances unless we moved it. The issue is that this new one has the ability to produce sexually, so we get aggressive local weeds…. Now, 70 per cent of the knotweed here is the bohemian knotweed.”

According to the Invasive Species Council of British Columbia, there are no bio-control agents available to control knotweed. While mowing and cutting it can be effective, it must be done repeatedly for five years to exhaust the plant’s roots.

When left alone, the weed spreads quickly along the banks of streams and other water bodies, easily growing to a height of four metres in just two months. It can grow four to eight centimetres a day.

The dangers are twofold, said Strelau.

“First, there’s the ecological side,” he said. “It’s killing out a lot of plants, it’s changing the soil, it’s definitely hurting invertebrates and other things like that. Then the economic standpoint: It’s costing us a lot of money to treat it and it definitely destroys infrastructure. If it’s found on your property, your property value significantly decreases. So it’s a big issue in that sense. It destroys buildings.”

He added the B.C. realty community is pushing for an effective treatment.

Neal Aven, Surrey’s urban forestry and environmental programs manager, said Surrey has a few hundred known invasive plant sites, and that list continues to grow.

The city also works to educate the community, seeing as residents are often the ones depositing invasive species in the first place, he explained.

“One of the ways invasive plants get into our forests are from dumping. People dumping yard waste…. They chuck it over the fence into the forest,” Aven noted.

Last week, the Now reported that some locals were shocked to learn the city was spraying invasive plants with glyphosate.

In 2015, the World Health Organization found it to be “probably carcinogenic” in humans.

Retired Surrey teacher Ken Borrie told the Now while invasive plants like lamium are a nuisance, they are easy to rip out by hand.

SEE MORE: City of Surrey herbicide linked to non-Hodgkin lymphoma

“We would be happy to volunteer,” he said. “No need for chemical warfare.”

But Aven noted that in 2016 the WHO did a follow-up study with the UN’s Food and Agriculture Organization that “clarifies” health issues concerning glyphosate, which is a key ingredient in Roundup, a weedkiller produced by Monsanto.

This latest study concluded the chemical is “unlikely to pose a carcinogenic risk to humans from exposure through the diet.” It did, however, find “some evidence of a positive association between glyphosate exposure and risk of NHL,” or non-Hodgkin lymphoma.

With files from Tom Zytaruk


Just Posted

South Surrey church members ‘praying for accused mother… for the whole process’

Lisa Batstone’s second-degree murder trial continues this week in B.C. Supreme Court

City will ask Fraser Health to remove pay parking at SMH, Surrey councillor says

Surrey’s new council has already made parking free on neighbouring city streets

Health and Technology District breaks ground on new building

City Centre 3 is the third of eight planned buildings: Lark Group

Spawning salmon returning to North Delta’s Cougar Creek

It’s early in the season, but the streamkeepers are hopeful it could be a good year for returns

Former Surrey gymnast shining on rugby pitch for Bayside

An injury forced Brady Reeleder to switch sports, and now he’s thriving at his new endeavour

Winter weather hits parts of Canada

As some parts of the country brace for cold, parts of B.C. remain warmer than 10 C

B.C. teacher’s Amazing Race takes students on Canada-wide adventure

Agassiz high school students say they had the experience of a life time

Don’t sign USMCA until LGBTQ language excised, U.S. lawmakers urge Trump

The trade agreement, forged after 13 months of tense negotiations between Canada and the U.S. is scheduled for Nov. 30

US official: US intel says prince ordered Khashoggi killing

Vice-President Mike Pence told reporters that ‘the murder of Jamal Khashoggi was an atrocity.’

Giants serve up major defeat to Pats at Langley Events Centre

On the ice, Vancouver G-Men wrap up home stand with a 10-4 win over Regina Friday night.

Canada’s health system commendable overall but barriers to care remain: UN

The United Nations says Canada’s health care system is “commendable” overall but vulnerable groups still face barriers to quality care.

Unique technology gives children with special needs more independent play

UVic’s CanAssist refined seven prototypes aided by $1.5M government contribution

Kelly Ellard’s boyfriend has statutory release revoked

Darwin Duane Dorozan had several parole infractions that found him ‘unmanageable’

Most Read