Low yield on cherry tree?

Question:hello, i just discovered that this tree in the backyard of my new house is actually a cherry tree. i really did take care of it for that last 6 months i have been here. they yield is really...about 40-50 cherries in total and now i am seeing that the leaves have developed some kind of a disease...most of the leaves have holes in them. any idea what i should be doing to improve future yields and also get rid of this leaf disease?

Thanks
rrr

Answers:
I HAVE A CHERRY TREE AND IT IS 4 YEARS OLD AND IT STILL HASNT MADE CHERRIES, IT IS ALL ABOUT IF IT GET CROSSED POLLENATED OR NOT AND USE FUNGICIDE TO PREVENT DISEASE