Certified GKH Gardening Expert
Unfortunately, your photos did not come through. I am unable to see the damage in question. This could happen for a few reasons, though.
Wet soils, or tightly packed soils, will lead to disease. This can lead to improper nutrient uptake, as well. The additions of earthworms and mulch can help with this.
Another thing to consider will be how long it takes for them to fruit properly. It can take up to eight years to see any fruit production from the tree. If it is still young, then I would give it more time.
Here is an article for more information: