Whatis:

I am not sure why the leaves are so tattered. The blotchy marks on the skin of the apple is sooty blotch and fly speck. They are each caused by a fungal pathogen. The good news is it only cosmetic as the flesh of the apple will be fine. In fact if you polish the apple with a cloth you will notice that 75% will come off. Or peel the fruit before using it.

To prevent you, need to be sure tree is pruned with a loose open canopy to promote sunlight and air flow thruout. Often this disease issue is more common on home grown apples because most home growers do little to no pruning nor spraying. You can also preventatively spray your apple tree with a fungicide registered for use on apples such as

Captan 50 WP or Immunox (active ingredient is myclobutanil). Both these fungicides should work at prevention but not eradication.

Most often sooty blotch/flyspeck seems to appear later in the growing season when the apple is more developed. Where I am in SE WI it can occur late July-early September.

Thank you Spartan for such wise advice and so much appreciated. There are a lot of apples on that tree and it so good to know that it just affects the surface.