Curled-up leaves on some trees in Okotoks have sparked calls of concern to the town recently.

Town of Okotoks Urban Forest Specialist Gordon White says the culprit is the leaf roller, a type of caterpillar. Although the leaf roller will eat through leaves, he says the damage is considered cosmetic and otherwise healthy trees can be expected to recover.

"The name describes what it does to the tree," White says. "So, it rolls itself up in the leaf and feeds on the leaf and then will lay eggs and emerge into a moth afterwards."

He says the pest, which generally only has one life cycle, seems to have emerged earlier in the season than usual this year. He says lilacs, green ash and aspen are commonly affected, but the good news is the damage is cosmetic and otherwise healthy trees should be able to recover.

"Many of our deciduous trees, they put out a flush of growth in the spring and then as the summer goes on, they continue to put on new growth and new leaves," White says. "Any leaves produced after the insect has completed its life cycle won't be affected."

Because the damage to trees is considered cosmetic, the town doesn't treat for the pest. However, White suggests homeowners should keep their trees well-watered and mulched to give them a fighting chance against pests.

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