Translucent leaves having discoloration, in oncidium shoot! Help ☹️

[Constanciancy]

Hello lovely people!!
It has been more than 2 months since I've been trying to keep an oncidium plant alive & boy, oh, boy - it's hasn't been easy. Had to cut off most of the leaves coz they were turning blackish brown. A shoot developed which was doing just fine, until this evening when I noticed a translucent, discolored part in the newly growing leaf 😥 It looks quite like a bacterial rot but I'm not getting any smell yet. I'm attaching a few photos here... If anyone can tell me what in the earth just happened with the new shoot and which step should I take immediately, then it will be a HUGE help!! Thanks in advance!!

[SouthPark]

It could be a bacterial issue there. Is the orchid growing indoors? I grow some oncidiums, and the growing area has nice gentle air-flow.

And my strategy for watering is to have adequate drainage for the media ----- and nice air-movement, and also avoid spraying any water over the top of the plant. Water getting into the pockets in between leaves can probably lead to some bacterial activity, or plant cell-killing conditions.

Hard to say exactly what led to that rotting activity for that leaf. Maybe a systematic fungicide (eg. a phosphorous acid fungicide) sprayed into that region and allow for a dry-out could halt the rotting activity.

[Constanciancy]

Thank you!!
Yes, it has been growing indoors. Fungicide is quite uncommon around here 😅 But I'll try to find some. Moreover, it's actually hard to say abt the smell so perhaps it can be bacterial as well. I have another question - can hydrogen peroxide help in this rot situation?

[Ray]

It is likely erwinia.

If you can get a copper-based treatment, use it right away.

[estación seca]

Many Oncidiums and hybrids are cool to intermediate growing plants. If the growing space is quite warm, these become very susceptible to a lot of various bacterial and fungal rots. Species or hybrids of warmth tolerant plants may do fine in these circumstances.

What are temperatures in your growing area, day/night? Which plant is this?