Question
WHILE PRUNING i notice powdery mildew on leaves also a thick white substance on main branches that you  can wipeoff with your glove hand. what product can I BUY TO CORRECT THIS PROBLEM

Answer
John:
Can you send a photo of this stuff?  It may be an insect infestation, but would need to see it.  You can also snap off a twig and carry it to your local garden center/nursery for an ID too. Best to get an ID so as to get the best control for it.

Steve