Question: The leaves of my cotoneaster are stuck together in clumps. There seems to be a worm inside each cluster. What is it, and how do I stop it?

Answer: That’s a leaf-tying insect, and you’ll need to use a systemic insecticide next year. Make note of when you first saw the damage this year, then treat a couple of weeks earlier next year. It’s not life-threatening to the plant.