I called into your radio show with a question about massive leaf drop on a section of a 15 to 20 feet Crepe Myrtle Tree. Before you wasted time on research, I wanted to let you know that the issue has been resolved.
We cleaned up the area and no more leaves dropped and none dropped off a larger Crepe Myrtle about 30 feet away. My wife remembered she had a crew pressure-wash the house about 7 to 10 days ago and the problem appears to be from the over spray of the bleach solution.
The area of leaf drop was maybe 5% of the tree. Hopefully, leaves will come back on that area but it does not appear that we have any damage on the rest of the tree.