Persimmon Fruit drop

I have a "Coffee Cake" Persimmon, about three years old. This is the first year it has really set a fair amount of fruit. The fruit is about the size of a marble, now all of a sudden I'm having a lot of fruit drop. I'd say at least 1/3 of the fruit. Any ideas about what is causing this. I'm in zones 24 and 9.

I'd appreciate any help.
Thanks