Orange rings on Bulbophyllum bulbs ?
 

I thought I should post about these orange rings that are on almost every bulb of my Bulbo medusae. They have become soft spots on a couple of the bulbs and I am guessing that this is a fungus.

The questions are: how serious is it, should/can I intervene, and if so, what should I do?

https://farm9.staticflickr.com/8612/...32870757_z.jpg

https://farm8.staticflickr.com/7524/...33c7bb7e_z.jpg

I have not seen that before. Hopefully someone can help you. Good luck!

Might be past insect or snail/slug damage, idk.

First photo is likely damage from a burrowing insect. That pseudobulb may be a goner, if the insect is still inside. Second photo shows human-caused mechanical damage - you can see old knife marks at the edges of the blemish. Maybe a previous owner was a little careless with a razor blade.

Edit: second photo is damage from the same type of insect, but someone had tried to cut out the spot, not realising the futility of that course of action.

I've had occasional problems with rodents getting into my Bulbophyllums. Sometimes they just bite or nibble leaving marks like your first and second pictures, respectively, but sometimes they tear plant scompletely to shreds. If these marks are new I suggest putting out traps in your growing area ASAP, Bulbos have been the rodent favorite in my collection and they destroyed a few before I got rid of them.

If you're getting opportunistic infections where the plants have been chewed, cut out any infected spots and disinfect with peroxide. Fungi and bacteria can spread fast in Bulbos so you may need to cut back along the rhizome if a pseudobulb is already heavily infiltrated. Good luck!