'Made in Canada' wasps next step in battle against ash borer

Tetrastichus will join other parasitic wasps — both American and Chinese — released in 2016 to combat the emerald ash borer.

Tiny ‘Tetrastichus’ feed on borer’s larvae before killing hosts

Natural Emerald ash borers, native to China, were accidentally introduced to North America two decades ago, likely through unsecured shipping crates involved with international trading. (Minnesota Department of Natural Resources via AP)

This week the first batch of 'Made in Canada' parasitic wasps will emerge in the fight against the emerald ash borer.

Researchers at the Great Lakes Forestry Centre in Sault Ste. Marie  hope to rear between 10-12,000 of the tiny wasps, which go by the name Tetrastichus.

These wasps will join other parasitic wasps — both American and Chinese — released in 2016 to combat the borer.

Tiny, parasitic, all-Canadian wasps being reared to combat invasive emerald ash borer 0:59

Wasps target borer grubs hiding under bark

The Tetrastichus inserts its eggs through the bark and onto the ash borer grub feeding underneath.

Dr. Krista Ryall of Natural Resources Canada hopes the presence of these new wasps can help stem the spread of the borer, which so far has killed millions of ash trees in Canada and the United States.

"What we're hoping is that, over the long term ... it could be decades ... that as you have new ash regenerating, hopefully you'll have these wasps present and keep the emerald ash borer at a lower level," Ryall said.
The emerald ash borer's larvae will be hosts to a 'made in Canada' parasitic wasp, reared to combat the invasive borer. (Ed Czerwinski, MNRF)

The wasps will be spread across six new release sites in Ontario and Quebec, she said.

But the presence of this parasitic army shouldn't alarm anyone.

"They don't attack humans," Ryall said. "They don't bite or sting or anything like that. They're not like wasps that most people would think of."

"And this one in particular is very specific. It only likes to eat emerald ash borer. So really, that's its only host that it's out there looking for."

Hear more about Tetrastichus on CBC's Up North

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