Treating the orchids in my sickbay: Zygos, a Phal, and an Angraecum

[Ray]

Looks to me like you're dealing with acidovorax, a bacterial infection closely related (synonymous, to some) to pseudomonas infections.

It is very easily spread by water splashing, but may also easily be prevented by use of a topical disinfectant like Physan.

It may be treated with the use of copper compounds, like Phyton 27 or Southern Ag Liquid Copper.