What is it?
Ash Leaf Roller is a moth that affects ash trees. As the caterpillar grows, it rolls the leaf into a cone shape, where the larvae continue to grow until they reach the pupal stage. The adult moths emerge from the leaf cones, typically starting around mid-July.
Symptom
- Leaves are rolled up into cone shape.
Damage
- The insects do not cause harm the tree health, it is mainly aesthetic issue.
What to do?
- Keep your tree healthy, watered and fertilized.
- Encourage natural enemies like parasitic wasps can control caterpillar.
Other resources:
https://www.calgary.ca/parks/pests/ash-leaf-cone-roller.html