Q: How can I prevent powdery mildew on my magnolia tree? Last year the leaves were infected, mostly on the lower branches and fell off. The tree was completely covered with flowers this past spring.
Sylvia, you need to get an on-site inspection from a tree doctor, a certified arborist. The problem with your tree goes beyond the powdery mildew. It is under stress and so you need to call a doctor. Best And Happy Yardening, Nancy.