Why do the leaves of a magnolia tree have gray areas?
A sign of gray on the leaves of a Magnolia tree signifies mildew (mold). It can be caused by hot days and cool nights. Also if you water your tree during the hot, sunny days and it cools off during the night. I live in Canada so don’t know if you get catipillars there, but, if you do, look for web-like cacoon (gray) and spray with the proper environmentally insecticide. Your hardware store would have the correct brand for that particular tree. My bet is mildew (mold.
