My apple tree has had what appears to be two different diseases (See pics). I suspect is cedar rust (lightly spotted leaves) which I understand is more a nuisance than anything. The other is that many of the new tips that appear turn silvery and then die. Both of these diseases have been with the tree for a few years, but this has not seem to have affected the production. The main issue has been coddling moths. Any insight on these pics?

Also, I have proceeded to reduce my apples to one per spur, which is a new thing. I did this because my fruit has been way too small, and I intent to use fruit socks and it doesn't make sense to put so many socks on fruit that becomes June drop. The question is what activates the apple maggots and/or when should I start to sock the apples? They seem a little small for the socks right now but what do I know?

Thanks in advance!