Q.Azhalea Plants have Black powdery Sooty mold on Leaves and on stems
At home I have all Azhalea Plants have Black powdery Sooty mold on Leaves and on stems and dendralions DYING DUE TO WHITE FUNGUS ON STEMS

Certified GKH Gardening Expert
Yes, this is a bad fungal issue. I would recommend putting, both wettable sulfur in the soil, and dolomitic lime to bring the pH back to where it should be. The wettable sulfur will kill of any infection in the soil so that it will come back healthy. Here is an article for more information on the care:https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azaleas-noteworthy-shrubs-for-any-garden.htm