Winnipeg begins monthlong tent caterpillar pesticide program

Winnipeg is beginning its caterpillar pesticide program as tent caterpillars and cankerworms have made their presences known this spring.

An entomologist is predicting it won’t be a particularly bad year for tent caterpillar and cankerworm activity.

“What tent caterpillars do, they usually go on a 10-15 year cycle of increase and decrease and we’re starting to see a little of it. So there are going to be hot spots out there,” said entomologist Taz Stuart.

Stuart says some areas of the city will see both tent caterpillar and cankerworm activity.

The city began spraying for caterpillars Sunday night in Fort Richmond, Deer Lodge, and South River Heights.

Stuart says the city’s pesticide program is a great way to protect Winnipeg’s elm trees.

“Right now, using the BTK to spray it is the most biologically and microbiology friendly program to control them,” said Stuart.

Winnipegger Chris Schmidt started a tree banding company 20 years ago when he was 10.

“Banding your trees is an indirect way to reduce Dutch elm disease,” said the founder of Schmidt Tree Banding.

“We can see the effectiveness of what we’ve been doing in the lack of cankerworms in the area that we’ve been banding for 20 years. This is working.”

On top of the city’s pesticide program, Schmidt says the environmentally friendly sticky bands are a great way to stop cankerworms from laying eggs in the trees. But it can’t stop tent caterpillars as the females fly.

“If her eggs aren’t in the canopy when the springtime comes and they hatch, those cankerworms won’t eat the leaves,” said Schmidt. “How this is related to Dutch elm disease, the disease actually lives on a flying beetle, and what that beetle will do is actually attack trees with reduced foliage and canopy. That’s a sign the tree is stressed out.

“So these diseased beetles go after these trees as they’re more susceptible to the disease.”

Both Stuart and Schmidt recommend banding on top of pesticides to control the caterpillar population. Banding should be done between August and September.

Spraying is scheduled to occur Sunday to Thursday evenings over the next four weeks.