Fungus on azaleas
Look at photos of lichens on our website to see if this is what you are referring to. If so, no control is necessary. http://extension.umd.edu/hgic/lichens-trees-and-shrubs
Otherwise, please send photos of the fungus that you are noticing. Send photos of the whole shrub, around the base, and affected foliage/branches so we can see what you are dealing with.
I think this does look like a lichen but I had a neighbor who is a landscaper tell me it is a fungus that should be treated with oil, or the azaleas should be removed. I believe this is a Kickapoo azalea but my other deciduous azaleas also have the same growths. Help!
These are definitely lichens. They don't hurt anything.
He may be thinking of scale insects, but we don't see them here.