Worms On River Birch Trees

Q: We have a great river birch that is about 16 years old. About 10 years ago, we began fighting worms on the leaves. This year the leaves are nearly yellow. What is causing this? Dick – Ames

A: I think you have tent caterpillars. They live in a web. You can use the Ortho Max or any systemic insecticide. Maybe give the tree a little shot of iron. It’s not too late for the last application of iron. [early September]