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Close watch for spruce budworm in Newfoundland

A sixth-stage spruce budworm larva. - Joe Bowden photo
A sixth-stage spruce budworm larva. - Joe Bowden photo - Contributed

Research hopes to develop clear picture of budworm predation on island

To the spruce budworm, for much of its life, tree needles are tasty, and buds for new growth are particularly delicious.

A rapid uptick in the local spruce population will damage evergreen forests, as the budworm larvae eats, leaving behind patches of rusty and dead trees. It’s a serious concern for the forestry sector, given the loss of timber as a result.

An adult spruce budworm. — Joe Bowden photo
An adult spruce budworm. — Joe Bowden photo

An “outbreak” generally happens when natural population controls, such as temperature and natural predators, aren’t effective or are overwhelmed. And there is work ongoing to better understand what exactly that looks like on the island of Newfoundland.

“We don’t fully understand yet how different forest stands or different climatic conditions (…) might influence the survival of the local budworm populations. So we have a couple of experiments going on where we are studying budworm across different elevations,” said Joe Bowden, a research scientist with the Canadian Forest Service working out of the Atlantic Forestry Centre in Corner Brook, speaking with The Telegram this week.

As for predators, he said the researchers are working to better understand, as an example, the degree to which certain predators — species of spiders, wasps, flies — kill the budworm.

“There’s some fly species and wasp species (…) that lay their eggs or larvae inside the caterpillars, the spruce budworm caterpillars, at various life stages. So one of the fundamental questions is we still don’t fully understand that assemblage in Newfoundland. So, how many different kinds of predatory species are out there in the forest, and does this differ between different forest stands?,” he asked.

And would it be possible to encourage these predators in a natural way?    

Outbreaks of spruce budworm can run more than a decade and have cycled through the region every three to four decades, with the last major event in Newfoundland in the 1970s and 1980s. As The Telegram was told by the province’s supervisor of forest protection back in 2017, that event resulted in the loss of about 50 million cubic metres of wood, equivalent to about a 25-year wood supply at the time. The build-up started on the west coast and worked its way east.

Monitoring of spruce budworm populations is helped by community-based volunteers, citizen scientists, throughout Newfoundland and Labrador. This map shows trapping efforts on the island as part of the Budworm Tracker program. - Natural Resources Canada
Monitoring of spruce budworm populations is helped by community-based volunteers, citizen scientists, throughout Newfoundland and Labrador. This map shows trapping efforts on the island as part of the Budworm Tracker program. - Natural Resources Canada

Then and now, provincial and federal researchers and forestry officials have been watching for a re-emergence of those damaging numbers.

Officials are keenly aware spruce budworm populations have picked up and damaged stands in recent years New Brunswick and Quebec, while expensive spray campaigns have been trying to knock back the numbers and minimize the damage. These provinces were also affected by outbreaks before Newfoundland and Labrador in the 1970s.

“We know that the outbreak is ongoing in Quebec,” Bowden said, when asking about movement in the last few years there. He said they’ve pushed into new areas.

He explained the insect’s lifecycle includes time as a migratory moth, with the ability to travel great distances. “So we could be getting some of those migrants into the west coast of Newfoundland,” he said.

Newfoundland and Labrador has monitoring in place for spruce budworm. It has advanced with the Budworm Tracker citizen science program, where volunteers get a package to count, collect and ship back to researchers, giving a better view of budworm numbers, cycles and movements, including migratory budworm.

“The project was started to engage the public to help us, because we can’t be everywhere at the same time,” Bowden said. “We do rely heavily on the public to help us.”

Bowden said apart from the research, the citizen science work is ongoing. More on the Budworm Tracker program is available at budwormtracker.ca.

Twitter:@TeleFitz


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