Natural Resources Canada, an organization that has taken on the destructive, invasive emerald ash borer, has successfully raised a parasitic wasp (Tetrastichus planipennisi) that preys only on the borer in an attempt to stop its devastating effects on North American forests.
The federal organization has been importing the wasp from the U.S. Forest Service in Michigan since 2013 and releasing them in 12 different areas of Ontario and Quebec.
“We’re hoping to raise about 10,000 for this summer,” Said Krista Ryall, lead researcher on the project. “That will be enough to do five or six more sites across Ontario and Quebec.”
The wasps are seen as a “bio-control” method for taking care of the invasive and out of control ash borer.
“The wasps will eat and kill the larvae and then you get more wasps coming out instead of the emerald ash borer,” Ryall said. “Over time the wasp population builds up and we hope that they will help kill a fair number of emerald ash borer out there.”
In the wild, the wasps will breed, lay eggs, and die within about a month, but multiple generations of the wasp can be born and breed in a single summer. They are not native and will need to be continuously reintroduced each summer.
While labor intensive, this means that Canada won’t end up with a “woman who swallowed a fly” type situation where the borers are gone but the wasps are a problem.
The wasps, like the ash borer, are native to Asia and will not target humans or other species. The emerald ash borer has been present in Canada since 2002.
“The spread is a major concern,” Ryall said. “We’re finding that 99 per cent of ash trees are killed within five to seven years of emerald ash borer getting into an area and causing extensive mortality.”
The beetle is slowly spreading east and north, but researchers hope that the wasp will help slow, or completely stop, that movement.