Let's clear one thing or two:
- all these are not viruses
- viruses are really tiny DNA/RNA protein encapsulated "living" (they are counted as living now) thingies. The largest viruses are as big as some small bacterias. Viruses infect a cell, replicate inside it using the DNA/protein replication factory there, then move outside and go on infecting.
- Bacterias are single cells, with free moving DNA inside, they live on or in cells or in the fluids like sap. A bacterial infection smells… stinks in fact.
- Fungus, are multiple cells organisms (save the likes of yeast for example) so of even higher organization. They push in multiple cell organization a mycelium (think "roots" but it's the fungus itself) inside the plant. And if you see a white/green plush thingie out, it's the "blooming" fungus dispersing spores.
All these are in 3 different Orders of the living stuff around, it lefts plants, animals and Archaea (leave this for now) out of the picture. But don't take a fungus for a virus or a bacteria, you don't fight viruses in plants (to make things simple), and it takes different means to kill fungi or bacterias, the bad one that is, as some are beneficial (not our case here), orchids in the wild even need fungus to grow at first or for some all their life.
Now to get back to our problem:
- Viruses are less common than you think, so first choice will always be something else that can look the same (fungus, bacteria), and only a test can tell if there's really a virus possibly at work.
- If it stinks : bacterias
- if it smells mushrooms : fungus
- neither, it can be either!
- if something oozes, it's infectious, don't touch it, remove the goo with something disposable and off to the trash and disinfect and wash you hands.
Simple means to care about fungi and bacterias are copper (but it works preventively, outside the plant only), cinnamon (can't be more organic), then the available systemic chemicals (read out the little lines, it's not friendly stuff, for you and wildlife).
Basic caring is to dispose of the affected parts (with disinfected tools before and after), cut them large at least an inch from the infected part. Treat on the spot with at least a systemic fungicide. Treat the cut itself with cinnamon.
You can follow up with a copper based product to altern. Don't use copper on blooming plants or dendrobiums.
You can use as a more general mean a cinnamon decoction:
- 3 teaspoons of cinnamon powder in a tea bag/pouch
- in half a liter of alcohol (isopropyl 70° if possible, else the 70° Cooper formula will do)
- leave 24 hours then remove the bag.
- spray
- bactericide, insecticide, fungicide, miticide
- organic but not systemic
- DON'T spray the roots or flowers!
- you can spray every few days if needed as a complement.
I don't have the habit of peroxyde… AFAIK it's 3% peroxyde alone, spray all over, insist if a zone is bubbling… (I'd take a complete course on this as I've never read it in full still
Can't tell for a copper/peroxyde mix…
(I strongly encourage to read the STAUG pages and at least Sue Bottom's and a few other pdfs, it's the best input you can have right now in the world for orchids)