I had seen a fungal spot on the top leaf of my healthy growing vanda, and while removing (sharp knife) the fungal spot, I damaged the active growing portion.
Anyway, I treated the cut portion with mancozeb, but worried about the growing portion.
It is really good ..I have learned new things from the link. I have dendrobium plant.The root has brown rot,,leaves turn to red color... I guess it might be Bacterial Soft and Brown Rot......am not sure physan 20 is the same as physan ?