possible fungal infection

[santiago]

hello.
i've been having a problem with a purple-black spot that's been appearing on my plants


in this case is a leaf from a noid plant (possibly polycycnis), it is one of the most affected plants, and this leave had most of the lessions. it has also infected a couple of bifoliate cattleyas, two xylobiums, an oncidium fuscatum, a cyrtopodium, and some pleurothallids

[WhiteRabbit]

Good luck!