Toronto

Mississauga using helicopters to battle tree-killing pests

Low-flying helicopters will be spraying for cankerworms and gypsy moths for the next few mornings in leafy areas of Mississauga.

Aerial spraying program takes aim at cankerworms and gypsy moths

A helicopter sprays Btk, a naturally occurring bacterium, over a leafy part of Mississauga as part of the city's aerial spray program on Wednesday. (CBC)

Low-flying helicopters will be spraying for cankerworms and gypsy moths for the next few mornings in leafy areas of Mississauga.

The city's aerial spray program aims to control the insects in areas where trees have had 90 to 100 per cent of their leaves eaten in the past.

Cankerworm caterpillars — also known as loopers or inchworms — are known to emerge in the spring and fall and are most commonly found on hardwood trees such as oak, maple, and elm.

Jamie Ferguson, who is leading the city's efforts, says while trees can often recover and grow a second set of leaves, it puts them under tremendous stress. Last year, some Mississauga residents said it looked like trees were being eaten alive.

"That really uses up a lot of their energy and their stored resources, which means after a couple of years they really start to deplete and weaken," Ferguson told CBC Toronto.

"We obviously want to protect our tree canopy. It's very valuable for a whole suite of reasons."

Mississauga has struggled with infestations of worms in recent years. (Nicole Martin/CBC)

Wednesday morning — the spraying took place between 5 and 7:30 a.m. — was the first of three straight days of scheduled sprays for private and public land in specific parts of Wards 1, 2, 6, 7, 8 and 11.

The trees are being treated with Btk, a naturally occurring bacterium found in soil. Ferguson says Peel Public Health has studied the research on the treatment and provided assurances it won't harm humans or pets (unless your pet is a caterpillar).

A second round of spraying is being planned for next week, however that depends on the weather.

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