How bad is this situation

[Mark V]

I have never run into this (these) problem(s) before. There may be more than one malady but it has progressed from one blc. I got to several chids of different types. It starts off as a translucent, silvery spot on a leaf progresses to tan , then brown then black and finally dead and papery through the leaf. Soon after the air roots dry and die and all the leaves and P. bulbs shrivel. The plants continue to put out new growth but they are all going terminal. The disease is attacking Catts., Onc. Psychopsis, Milts. Phals. Pots. and zygos.