Azalea branch die-back
I've got a garden bed with 5 azaleas about 4 feet tall. One I've been pruning each year for the past couple of years as the branches are dying back. I took it to a garden center, and they said that it has some fungus that develops a triangular look on the branch flesh and becomes woody. Is this problem going to spread to the other azaleas or can I control it with something?