millions of white somethings on bark of weeping cherry
I was going to some pruning and noticed the underside branches were all dead. Then I noticed the entire branches were white. Millions upon millions (no exaggeration) covered the branches completely around. There were not on the leaves at all, only the bark.
They were smaller than a pencil point. Searching google didn't help me.
What are they and how do I get rid of them?