Extreme weather could impact invasive insect species, says Winnipeg forester

Winnipeggers love to complain about the harsh winters, but prolonged periods of extreme conditions might have an unexpected effect on certain pests.

City forester Martha Barwinsky told 680 CJOB Monday that researchers are looking into the cold hardiness of invasive insects like the emerald ash borer and elm bark beetle.

Extended cold snaps, she said, have the potential to impact over-wintering pest populations, although it won’t be clear how much until things warm up.


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“There has been some research done for the emerald ash borer, for example, and that research is continuing for cold hardiness of the pest,” said Barwinsky.

“What we see so far from the research is that a good portion of the pest population can be killed with sustained temperatures of -34 Celsius.”

That temperature, however, has to be reached under the bark, so even with recent windchill values near -50, it may not necessarily be cold enough.

“Even if there’s larvae that are lower down in the trunk and that trunk is surrounded by snow, that’s also insulated,” she said.

“It’s important to note it isn’t necessarily the extreme cold during the winter months, but it’s also the time leading into the winter and the time coming out of the winter that have an impact on hardiness.

“I’m hoping this extreme winter will have an impact on beetle populations, but I’m looking really at what’s happening with the transition of the seasons, which will likely have a bigger impact.”

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