Oobius agrili, parasitic wasp, introduced to Ontario to fight emerald ash borer

There's a tiny new weapon being used in the fight against the destructive emerald ash borer in Ontario.

Benefits of introducing parasitic wasp 'greatly outweigh the risks,' entomologist says

Barry Lyons, a forest entomologist for Natural Resources Canada, stands next to two "oobinators" full of oobius agrili eggs. (CBC News)

There's a tiny new weapon being used in the fight against the destructive emerald ash borer in Ontario.

The federal government recently approved the introduction of a foreign breed of parasitic, non-stinging wasp that destroys ash borer eggs from within.

The oobius agrili parasitic wasp is very small and doesn't have a stinger. It lays its eggs within emerald ash borer eggs, killing the host egg. (Houping Liu/Michigan State University)
Scientists are now starting to release them into the National Capital Region.

In their native China, the Oobius agrili wasp is the natural enemy of the emerald ash borer.

The wasps lay their eggs inside the eggs of the emerald ash borer.

The wasp larvae eat the contents of the emerald ash borer eggs and then burst forth from the destroyed eggs as fully formed wasps to search for new eggs.

There are two types of the wasps approved for use in Canada: one type attacks emerald ash borer larvae and were approved two years ago, while the second type attacks the eggs and were approved last month.

'Not going to eradicate emerald ash borer'

"We don't expect we're going to get 100-per-cent control, we're not going to eradicate emerald ash borer," said Sean Barker, director of Eastern Ontario Arborists Inc., which works to stop the spread of emerald ash borer in Ottawa.

Sean Barker, director of Eastern Ontario Arborists Inc., says he hopes the wasp will help control the emerald ash borer population. (CBC News)
"I don't believe that's even in the realm of possibility but keeping it at manageable numbers and controls would be considered a success. ... Just having the opportunity to save trees is what we're hoping for."

Barry Lyons, a forest entomologist for Natural Resources Canada, worked to bring the wasp to Canada.

He said the Canada Food Inspection Agency is concerned the wasps could target a few species very similar to the emerald ash borer, but that the "benefits greatly outweigh the risks."

Lyons has been installing "oobinators" full of Oobius agrili eggs across areas affected by the emerald ash borer.

His department will now have to monitor the effectiveness of the wasps to see if they start cutting into the emerald ash borer population.

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