As has been said, need more info...
Can you show a piccie of the plants, and also more fruit? Also, we need to know if this is just skin-deep or if it's affected the flesh.
When did signs first appear & is it spreading?
What %age of them is affected?
Where are you growing them? (in or out?)
A description of taste & a cross-section photo (going through the brown bit) would help too.