I noticed Gage mentioned Listerine, which is a good option if you can't find a fungicide. But do not use the mint variety. It needs to be the regular brown stuff. The mint type would be hard on the plant. Physan 20 is usually available in the U.S. and is a good fungicide/bactericide. Also hydrogen peroxide should not harm the roots and will help kill any bad organisms.
I noticed Gage mentioned Listerine, which is a good option if you can't find a fungicide. But do not use the mint variety. It needs to be the regular brown stuff. The mint type would be hard on the plant.
Neem oil won't suffocate your vanda, just check online for application methods. Also when you do get a fungicide/bactericide also get a sticker solution to mix w/ it. It was recommended to me by the farm store, and it makes the mixed solution adhere to leaves so the solution cannot be washed off easily when water splashes the leaves.