I have 5 persimmon trees: 3 Fuyu (one 4-yrs. and two 2-yrs. old) 1 Tanenashi (one 1-yr. old) 1 Eureka (4-Yrs. old) Except for the Tanenashi, they all bloomed and set fruit this year. The 4-yr. old Fuyu has bloomed and set fruit each year but most fell off. The 2nd year it held 2 fruit. The 3rd year it bloomed profusely and set most all but one fell off. This year it did the same thing and every last one fell. The 2-year olds are still very small. This year they bloomed and set one tree seems to be holding 2 but the second tree has dropped all fruit. The Eureka has held fruit every year I have had it and each year it holds progressively more fruit, although it also drops fruit. What might the problem be? All trees seem very healthy, especially the 4 yr. Fuyu which has extraordinary growth.
Premature fruit drop is likely due to water stress and or pollination issues.
Too much nitrogen in the soil can also cause premature fruit drop.
A soil test can help you determine the amount of nitrogen in your soil.
Here is an article to refresh you on the care requirements.