City targets caterpillars with Btk

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This article was published 29/05/2015 (4011 days ago), so information in it may no longer be current.

City crews will take aim at forest tent caterpillars Sunday night in the north part of the city.

Ken Nawolsky, Winnipeg’s superintendent of insect control, said the $100,000 effort will target Margaret Park, Templeton and Garden City, where the infestation is most severe, and then move to adjacent neighbourhoods.

Nawolsky said the forest tent moth population is mobile, travelling from 160 to 320 kilometres per season.

Last year, the Interlake was hit with the infestation, he said, adding the city wants to curtail the spread for next season.

“Next year, we expect them to be throughout all parts of the city,” Nawolsky said.

Forest tent caterpillars chew on tree leaves, with the tell-tale shot-hole appearance.

Nawolsky said the damage is unsightly but not fatal to trees, as leaves will re-emerge three weeks later. However, he said the loss of leaves does stress a tree and makes it more susceptible to disease and other insects in future years.

The infestation hits in cycles, every 12 to 15 years, Nawolsky said. The last infestation in Winnipeg was 2002.

He said the caterpillars favour elm, maple, ash and ornamental trees.

The city will spray boulevard trees with an organic product called Bacillus thuringiensis var. kurstaki, commonly referred to as Btk.

The forest tent caterpillars eat the Btk, lose their appetite for the leaves and die two to three days later, he said.

Homeowners can spray their own trees, Nawolsky said, adding the spray is sold at most home and garden centres.

Homeowners can apply to exempt their property from spraying by contacting 311. There is a 30-metre buffer zone.

 

aldo.santin@freepress.mb.ca