Oncidium pseudobulbs seem to be rotting, can/should I do anything at this point?

[bateaux_mousse]

I've had this for just over a month, a few days ago I noticed some brownish yellow areas of the pseudobulbs that have since become darker and softer. I'm not sure if this is an infection or what, some sources have indicated this is normal for oncidiums that are depleting the old growth in favor of the new. Unfortunately the only new growth on this one isn't big enough to separate either way, so I don't know if I have any options besides wait and hope. I pulled a little media off the top and the roots look good. They were in a tight mass from being grown in a foam plug and I thought separating them might do more harm than good, but there are new tips branching out all over. The leaves still look great too, except for one of the small bottom ones that has a streak of brown near the base where it connects to the pseudobulb. Can anyone make a diagnosis or recommendation?

[WhiteRabbit]

Hmm ... I have had at times p-bulbs (1 or 2) turn soft and yellow with no cause I could discern, and the plant(s) went on to do fine, but I have also had 'mysterious' pbulb rotting that turned out to be from fusarium wilt. If you see more roots apparently rotting starting at the top (a symptom I noticed on a fusarium plant) I'd definitely be concerned. You may want to isolate this plant from others, as well as be sure any tools, pots used for this plant are well sanitized before use on any others.

I hope others have some ideas! Good luck!

[Dollythehun]

I've had something like this happen twice. Last year on a new Dendrobium growth and a few days ago know an Oncidium.

In the first case, I was advised to cut out that growth and treat with cinnamon. I used phyton 20 on the plant and cinnamon on the cut.

On the oncidium, I was unable to cut the bulb out, so I twisted it off and treated as above. It was smelly and soft. We'll see what happens. The roots in both cases looked great and I was glad I had been disinfecting my watering containers.

Someone with more experience will chime in soon.

[estación seca]

I've seen that happen when they didn't get enough water for a very long time. I've also seen it happen when they were too hot and too wet. The medium looks quite dry in the photos. How often have you been watering? How warm has it been, and what is the relative humidity?

[bateaux_mousse]

Humidity is usually 40-70% this time of year, temps mid 70s to mid 80s lately. For my oncidiums I do a good soak once a week and a top-off whenever I can't see any moisture condensed on the inside of the pot.

[estación seca]

I don't think you're watering enough. Oncidiums shouldn't get close to dry while in growth. They can die in the manner yours are when they don't get enough water while pushing new growth. A lot of people here on Orchid Board report watering them 3-7 times per week during the growing season, and some stand the pots in dishes of water.

[Dollythehun]

ES is correct. That does look dry. They are thirsty plants, my Sharry Baby needs watered every other day and it's in an 8" pot.