As spruce budworm numbers rise, so does the battle against them — except in Gros Morne

Nfld. & Labrador

A spraying program is expanding to try to lower the insect's numbers across western Newfoundland, but Parks Canada has opted out of the program and is letting nature take its course.

Spruce budworm can defoliate spruce and fir trees, and their numbers are rising in western Newfoundland.(Eric Moise/Canadian Forest Service)

A spraying program is quadrupling to battle rising spruce budworm numbers in western Newfoundland, but Parks Canada has decided to opt out of the effort and let nature take its course within Gros Morne National Park.

About 140,000 hectares of forest, from the Port au Port Peninsula northwards to Castor's River on the Northern Peninsula will be sprayed from the sky with biological insecticide BTK beginning in mid-June.

That's almost four times the area the provincial government sprayed last year when it began an early intervention spraying program against the insect, whose ravenous appetite for spruce and fir can ravage forests — a major outbreak in Newfoundland in the 1970s affected 90 per cent of the island's trees.

Scientists aren't calling the current circumstances an outbreak just yet, but the numbers of budworm in the trees is increasing — fuelled by moths that lay budworm eggs carried over on air currents from an outbreak in Quebec.

"A few years ago, there was barely an insect on a tree that we could find in the research that we were doing," said Eric Moise, a research scientist and entomologist with the Canadian Forest Service, based in Corner Brook.

Moise said researchers are now seeing branches with 30 to 40 spruce budworms eating away at them. It's too early to peg bug numbers at this point — populations are counted in the fall — but the trend, and warnings, are clear.

"Just looking at sort of the contemporary data that we're collecting now, we certainly have no reason to believe that it would be a light outbreak … we would be surprised if there wasn't a good amount of tree mortality in the coming years, if not for the [spraying] program," said Moise.

Eric Moise, a scientist with the Canadian Forest Service in Corner Brook, has been researching what natural predators spruce budworm has in Newfoundland.(Bernice Hillier/CBC)

Gros Morne a no go

But that early intervention program won't be going ahead in Gros Morne, an area estimated to hold about 10 per cent of the current budworm population of concern, according to Parks Canada's Roger Steadman.

The provincial government asked to include the national park in its spraying program for 2021, but after a public consultation process the park chose not to. BTK is a naturally occurring bacteria, approved for use in organic farming, that kills the budworm when they eat it and doesn't affect other species of animals, plants or humans, but it's too much of an intervention for the park's liking.

"When we look at the spruce budworm outbreak from a Parks Canada perspective, it's a natural process," said Steadman, a project manager with the western Newfoundland and Labrador field unit.

"It's really critical to the forest being healthy and renewing itself. So for a national park, that natural process really needs to be allowed to continue unless there's an overwhelming reason not to."

The feedback the park received "varied greatly," said Steadman. Forestry industry representatives sided with spraying, citing economic concerns for timber, while environmental groups weighed in against it. General public and Indigenous group feedback largely sided with the latter.

No spraying virtually guarantees spruce budworm will kill off trees, and Steadman said Parks Canada will be preparing to make sure visitors understand why parts of the park are dying in the coming years.

The provincial government's Department of Fisheries, Forestry and Agriculture declined an interview, but said in a statement it plans to conduct insect count surveys this fall "to determine the effectiveness of this year's program," including in spots around the park.

New Brunswick has seen success by adopting an early intervention spraying program against spruce budworm.

Spraying success

While Gros Morne will stay BTK-free, scientists will also continue to use the area to research spruce budworm, with the park acting as a control site for the sprayed forest around it.

"We'll be able to look at comparable sites within the park and then ask a series of questions about sort of the management versus no management scenario, and what that means for budworm dynamics, as well as various other aspects of forest ecology," said Moise.

Early spraying for spruce budworm has proven to be a success elsewhere, in terms of saving forests for their economic value. New Brunswick adopted the strategy in 2014 to protect itself from the Quebec infestation, a move that has been credited with protecting timber and keeping forests intact.

"By all accounts, it's been very effective in that jurisdiction," said Moise.

Scientists like Moise are working to better understand natural predators of spruce budworm in Newfoundland, such as certain wasps, in the hopes that those predators, instead of spraying, will be able to do the work in the future.

"It will certainly help us in the context of the early intervention strategy, because ultimately the goal is not to eradicate one worm, but to bring them down to a level where natural enemies can take back control of those populations."

With files from Newfoundland Morning

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Credit belongs to : www.cbc.ca

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