New study shows Emerald Ash Borer can survive extreme temps

Dr. Amanda Roe, a Natural Resources Canada (NRCan) forest research scientist based in Sault Ste. Marie, was part of a study of the Emerald Ash Borer that came up with a surprising outcome. 

It showed the insect can survive at extreme cold temperatures.

Dr. Roe said it means it can live through extreme winter conditions and attack ash trees anywhere they grow in Canada.

"Insects can do some really amazing things to avoid freezing because they're cold blooded so they don't generate heat," Dr. Roe said. 

"They actually manufacture compounds that act like anti-freeze and they store that in their blood," she added.

The new research on the Emerald Ash Borer, first detected in Michigan and parts of southwestern Ontario in the 1990s, shows the bug can withstand much colder temperatures than previously believed. 

The borer destroys these ash trees by eating it's way into their trunks.

It also means the ash borer could be more difficult to eradicate than anticipated. 

It could affect Elliot Lake and other Northern Ontario communities which have lost ash trees but had hopes of planting a new generation of them.

Dr. Roe noted the ash borer's ability to survive the most recent extreme polar vortex event.. 

"Winnipeg got very far down below the published freezing point for the Emerald Ash Borer, and yet they survived those conditions."

Fellow NRCan research scientist Dr. Chris MacQuarrie and research technician Meghan Duell also played key roles the study.

Published in the journal Current Research in Insect Science, it shows that the overwintering insect was able to survive the polar vortex that hit Winnipeg and other parts of Canada and midwestern United States, in 2019.

The group of scientists discovered that some of the bugs were able to survive when their body temperature dropped to -50 degrees Celsius.

The research team led by University of Western Ontario Biology professor Dr. Brent Sinclair had earlier found the insects, when located around Barrie, froze and died near -28 degrees.

"I was surprised they were in Winnipeg. The cold tolerance of those animals is incredible," Dr. Sinclair said

In Winnipeg, "they were freezing at -46 degrees celsius and some survived at -50 degrees Celsius."  

"Their blood had so much glycerol in it as an antifreeze that it was more like Jell-O than blood," said Duell, the postdoctoral researcher who made the measurement in lab-based experiments.

"Right now we know there was a population (Emerald Ash Borer) in Winnipeg. It hasn't been detected any further west," Dr. Roe explained. 

"But various cities such as Saskatoon, Edmonton, Calgary have a very high number of ash trees. If the ash borer ever got in they would lose a large number of trees. That would be devastating for those cities," she went on.

She also said that the bigger point that comes from this piece of work is that scientists have to be cautious.

"We do need to take into account that populations may be different because they're exposed to different environmental conditions," Dr. Roe concluded.

The work that produced the study was supported by a joint grant from the Great Lakes Forestry Centre of NRCan and University of Western Ontario's  Faculty of Science.