Identify Azalea Disease

Question

I have noted a light bluish-green, algae-type deposit on the branches of my very mature azaleas in southern New Jersey. I planted these over 30 years ago and do not want to lose these specimens.

Answer 1

It actually sounds like they have developed a lichen, which is not harmful to the plants. This article will explain more about them:
https://www.gardeningknowhow.com/ornamental/fungus-lichen/treatment-tree-lichen.htm