Forest tent caterpillars cover a tree trunk in Saskatoon. (JT Marshall)

By CKOM News - Will Mandzuk

Cankerworms

Summer pests return to Saskatchewan

Jun 24, 2023 | 4:32 PM

Cankerworms are slithering their way back up trees, but what can people do to prevent that?

According to the owner and manager of Dutch Growers, Rick Van Duyvendyk, there’s a certain product that will help people out.

“There’s this product called BTK and you spray it on the leaves. The caterpillar then eats it, they get a tummyache and they die,” said Van Duyvendyk.

According to Van Duyvendyk this isn’t the only way to stop cankerworms either.

“In September the male moth will fly around the tree and the female will climb up the tree, but if you put a plastic covering around the trunk of the tree, you can put a sticky product called tango foot and it catches the moths climbing up the tree,” said Van Duyvendyk.

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The city provided this statement in regards to the cankerworms:

“Cankerworms are an aesthetic pest that are an annual issue for Saskatoon’s urban forest. These insects are a common defoliator and one of the many organisms that co-exist with our trees. While they may change the appearance, these pests do not have a significant effect on overall tree survival. Trees wrestling with cankerworms may experience heavy defoliation but, unless there are underlying issues, the trees will recover and produce new foliage.”

The fall and spring cankerworm species often feed during June and July.

Cankerworms aren’t the only insects that can be a nuisance to people in the summer months. Leafrollers are also making their presence known on trees.

Like the name says, leafrollers roll up leaves to make a cocoon.

“Once they roll up the leaves, there’s nothing you can do,” said Van Duyvendyk. “But you can spray them with the BTK before they start to roll up the leaves to stop them.”

These insects, just like the cankerworms, do not harm the trees in any way.

“Eventually what will happen is a parasitic wasp will climb inside the leaf and kill them that way but that’s a natural way that happens over time,” said Van Duyvendyk.