Prepare for cankerworm ‘population boom’ in Saskatoon: Entomologist

Cankerworms are abundant in Saskatoon trees this year.

Entomologist Sydney Worthy tells 650 CKOM that we will see the cankerworms in high numbers for at least another year and that city residents can expect an outbreak to occur every decade.

“After a long period of low population number or dormancy, they kind of just more or less explode into this population boom.”

Cankerworms are primarily found on elm trees and can often be seen hanging from silk threads underneath infested trees. Worthy explained that we will see changes in the trees as the worms try to keep themselves alive.

“The worms will compete heavily for (those) elm resources, and they will defoliate a tree trying to do that. At the same time, there is going to be a lot that can’t get any food, and those ones will die off, (and) that’s when we start to see the cycle repeat itself.”

Worthy said the elm trees will recover in July as the outbreak winds down.

The City of Saskatoon recommends tree banding to deter the number of cankerworms in one’s yard. Bands can be placed on private trees in March or September to help prevent females from laying eggs in host trees.

The bands should be removed in summer and winter to prevent the trunk from rotting.