Crep Myrtle tree
I have a young crepe myrtle tree in full sun. It has developed a white moldy looking substance only on upper most new leaves. We live in zone 9. I have a drought resistant garden. There are small stones under tree that acts as a cover to retain moisture. No flowers yet. I sprayed it with deer defense.??? Thank you for your help! Genevieve
It sounds like your tree has Powdery Mildew.
These links will help you.