It's alive: Crews find 1st emerald borer beetle baby in Winnipeg ash tree

The knotted signs of an infestation were discovered last fall, but this week Winnipeg forestry crews found their first live emerald ash borer beetle larvatucked beneath the bark of a St. Boniface tree.

Crews confirmed a fourth infected tree on Wednesday and uncovered the first documented borer larva under its bark,said borer expert KristaRyall.

Ryallworks for Natural Resources Canada's forestry branch andis in town training city crews this week on how to spot infected ash trees through a bark-shaving method she devised.

The firsttree in Winnipeg confirmed to be housing the invasive beetle species from China was located on Cote Street, in the Archwood neighbourhood, in November. Crews have since found three more in the area.

In Ontario,Ryallhas watched the beetle chew through "99 per cent or more" of municipal ash populations within a decade of its arrival, spreading out a few kilometres every yearfrom the first site of infection.

"It's a very devastating insect," she said. "You may have one per cent [of the trees]lingering for a while and then the beetle gets them, too."

It was first spotted in North America in Detroit and Windsor, Ont., in 2002. It's since popped up in Montreal, Toronto and Hamilton, where it has costmunicipalities millions of dollars to fight.

It's possible Winnipeg could lose all of its roughly 350,000 ash trees 202,000 of which line city boulevards andstreetsideswithin that decade timeframe, too. Researchers with Natural Resources Canada estimate it could cost about $200 million for the city just to cut down and replace those 202,000 trees.

It's still early days, andRyallsaid there's a chance Winnipeg's cold winters could slow the developmental stage of the beetles and thereby delay the spread.

The city also has more tools at its disposal for stemming the spread thanks to the trials and tribulations of eastern Canadian communities that were caught even more unprepared.

City gears up to fight emerald ash borer

7 years ago

Duration 1:54

The invasive beetle has devastated ash tree populations in parts of Ontario and the U.S. but Winnipeg might have some advantages.

Female borers can fly 10 to 20 kilometres, Ryall said. After landing and depositing eggs on an ash tree, the larvae eventually carve out "serpentine" galleries as they develop and eat their way through the tree, Ryall said.

That's theexplanation for the short-distance spread. It's humans hauling firewood or other lumber infected with borers that are likely to blame for the bug making its debut in Winnipeg.

"I would suspect that maybe what we're seeing here, somebody brought some camp firewood from an infected area, brought it here," she said.

Apart from chopping down and destroying infected trees, one management option on the table is injecting so-called "high value"trees with a vaccine-like insecticide.

City of Winnipeg forester MarthaBarwinsky said the injection would helppreserve some trees and slow the spread.

That method has the advantage of protecting trees deemed special, although such trees need to be injected every couple of years to maintain immunity. Those costs add upeach injection runs about $165 for an average-sized tree.

Homeowners with ash trees should keep an eye out for increased woodpecker activity (they eat borer larvae) and external signs of damage to bark, Barwinsky said.

"It's tough to detect," she said, encouraging anyone who suspects they know of an infected tree to report it to 311.

The 2,000 dots on the map below are a random sample of Winnipeg's green ash trees, the second-most common tree in the city. The data reveals although the tree was widely planted across the city, there are high concentrations in newer neighbourhoods, whichexperts say are likely to become the problem areas with the appearance of the emerald ash borerin Winnipeg.

View the map on mobile here.