I have five apple trees for about five years. They have been unsuccessful, in the sense that each year the leaves become blotched and the apples are scarred. I noticed this year when the blossoms came on the trees the presence of black flies. I sprayed them with soapy water, but feel it was already too late. I am uploading before photos of a typical blotched leave and a scarred apple.

What advice can you give me to solve this problem.