Posted: 13/08/2017 at 20:48
One of the many forms of Scab or Blackspot. Some varieties of Cydonia are very prone to it. I have tried pouring a systemic fungicide into the roots of ours, but it still makes no difference. As said collect up and burn the fallen leaves.
As far as fruiting is concerned, does it flower? They actually need a very warm Spring to produce fruit. If no flowers then the Blackspot is reducing the amount of food the tree needs to produce flowers. Try feeding heavily.