Cankerworm population lower than previous years

The weather is getting warmer, and creepy crawlers are back.

Cankerworms hatch at this time of year. The worms are defoliating insects, which means they consume leaves and damage trees. Russell Eirich, manager of open space services with the City of Regina, said the city keeps an eye on the cankerworm population to determine when and where to apply pesticides.

“We do monitoring counts throughout the city and we try to determine or predict where we think the worst areas are, and then we’ll respond if they exceed a threshold,” he said.

According to Eirich, one neighbourhood in particular has a high population of cankerworms this year.

“What we saw from our counts earlier on in the year was that we knew that the General Hospital area would be impacted, so we set up a spray program to spray approximately 1,000 trees in that area,” he said.

“Most other areas were well below the threshold, and for that reason we’re not doing the rest of it.”

Eirich said areas with low cankerworm populations do not get a treatment, even though the pests can damage foliage. Eirich said trees can grow back their leaves and avoid major damage.

“There may be a tree or two or three in a very focused area, but we don’t do a single tree spraying,” he said.

“It’s not financially viable for us. But we do it when we’re talking like large-scale areas.”

READ MORE:

• Early reports of Ticks, but they’re not on the rise says expert
• City of Regina begins banding trees in war against cankerworms
• Bugs: what to know and how to deal with them

He noted that population numbers are much lower than previous years.

“There’s been way way worse years where we’ve seen the entire city defoliated,” he said.

“We’re built so that we can spray up to 30,000 trees in a season, so 1,000 trees really isn’t a whole lot. We didn’t spray any trees in 2023, and I think it was in 2022 – going off memory – I think we were in around the 5,000-tree mark, so we’re kind of at the bottom of what it could be.”

The cost of the spraying depends on the size of the area being covered.

“Typically, I think we’re probably in around $10 a tree when you work in your staff time and product usage and things like that,” Eirich explained.

“We’re capable of doing it on a large scale, but right now its a low-to-moderate sort of response that we need to do this year. It’s just responsible pesticide use to try to keep the spraying to a minimum at this point.”

Spraying in the General Hospital area cost around $10,000, according to Eirich.