Azaleas with Discolored Leaves

Hello, I have 3 mature Encore Azalea's that have little black specs underneath leaves, probably mites. I started seeing them last year. Now ALL the leaves are discolored but they are not falling off. Last year the Azaleas bloomed even with this problem. Since its almost spring, I would like to trim. How much should I trim? Can I just remove the discolored leaves and or trim branches? Also what can I use to make sure these mites don't come back?
Thanks! From Delaware

 

Yes: they are buggy. Take samples to an independent garden center and ask what pesticides they have that would be suitable for this particular issue. Instead of cutting them back and adding insult to injury. (Also if they haven't bloomed yet this year you will be preventing flowering if you prune right before they bloom - because the flowers each year come from terminal stem buds formed the previous summer).

 

It looks to me as though your azaleas are infested with Azalea lace bug, Stephanitis pyrioides (not to be confused with the beneficial lacewing).
Compare to: http://oregonstate.edu/dept/nurspest/Azalea_lacebug.pdf

Various species of Lace bug (Stephanitis) also attack Rhododendrons and Pieris. They have a reputation for being difficult to eradicate completely. It sounds drastic but I know some people remove afflicted plants before the insects move to healthy ones nearby.

I would take Ron's advice to consult with someone knowledgeable to confirm identity and suggest ways to at least control it.