City completes treatment of ash trees

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This article was published 27/07/2018 (2977 days ago), so information in it may no longer be current.

The last of the ash trees the city hopes to save from the emerald ash borer this year were injected with insecticide Friday.

Crowded under the shade of a leafy green ash tree in St. Vital Park, city councillors and representatives from the emerald ash borer control program announced 1,100 of Winnipeg’s urban ash trees had been treated in the lst two months.

Thanks to a donation from Trees Canada and BioForest Technologies, the city was able to inject 100 more ash trees with the TreeAzin product — a natural insecticide made from seeds of the neem tree that kills off the invasive, wood-boring species when it munches on the canopy — than it originally planned to. The donation of 12 litres of insecticide is valued at $6,800.

“Every bit helps,” Ken Nawolsky, superintendent of insect control in Winnipeg, said during an interview Friday.

“It’s really important that we inject as many trees as we can because that means one less tree is susceptible to the emerald ash borer, and if the beetle happens to attack that tree, they won’t be able to reproduce and then spread.”

The 1,100 trees, which the city hopes will now be fully protected from an ash borer threat, make up about 0.3 per cent of the city’s total ash canopy. The city plans to treat about 28,830 (eight per cent of Winnipeg’s total ash canopy) trees over the next decade because saving the trees is both difficult and expensive.

The emerald ash borer was first discovered in Winnipeg in November 2017. When the insect lays its eggs, the larvae embed themselves into the tree bark and block the flow of nutrients and water to the rest of the tree; they essentially “strangle” ash trees, said Dorothy Dobbie, a Tree Canada board member.

The insect can destroy an entire forest in 10 to 15 years, Nawolsky said. “What we’re trying to do is slow down the progress and movement of the emerald ash borer, so that we’re able to manage it better and then replace the trees that are dying so that we don’t lose them all at once.”

This year marks the start of the long-term fight to protect Winnipeg’s ash trees, he said, comparing the beetle battle to the city’s decades-long fight against Dutch elm disease.

Up to 800 ash trees will be removed by the end of the summer. Those trees, mostly in the Archwood neighbourhood, have been marked with purple dots.

Along with tree removals, the city will also continue doing “beetle surveillance” throughout the second half of the summer, by sampling tree limbs to see if there is any insect activity, Nawolsky added.

maggie.macintosh@freepress.mb.caTwitter: @macintoshmaggie