The rule of thumb, here, is the fruit is MOST attractive to the whitetails after the first frost.

That being said.......the fruit drops earlier than that....and they WILL be on them earlier than that.

Opening day, '07.....I noticed every deer that came near my stand was funneling through this one little area. When I got down......I walked over to that area. Persimmons. There were several on the ground. This was September 8th in NC.....and a LONG ways from our first frost.

I'd say.....if you can see the fruit.....they'll use it as a food source.