It's time to check your trees for Black Knot. Arborist for the Town of High River Darlene Donovan says it's not hard to see if your tree's infected.

"It's a fungus, and you can't miss it. It's a black knot that's quite visible on the Prunus varieties, so that's your Schubert Chokecherries, Maydays, and that sort of thing. It's really easy to see the fungus."

She says it's important residents prune out the disease and dispose of branches properly.

"The problem with it is it's airborne, so it can spread from the wind, the rain, birds, bees, that sort of thing. So it's really important that residents prune that out of their trees and dispose of it by either sending it to the landfill or burning or burying it."

Donovan says the fungus can kill trees in the prunus family like chokecherry and mayday trees.

"It can actually kill the tree. What happens if it's left for too long it'll move from the branches and it can move into the trunk of the tree. And once that occurs, the tree is pretty much done from there."

Donovan says it's important for residents to prune away the fungus as soon they see it, as the disease spreads easily to neighboring trees.