Is this fusarium on my oncidium? Or?

[meliana]

One of my NOID oncidiums-- when I bought it, it looked like mechanical damage, but it's spread quite a bit and the purple makes me worried. Right now it's confined to one of three bulbs and the rest of the plant is doing well, good roots, just finished flowering and sending out a new growth right on schedule.

From the same nursery, a phal that I bought has a sickly yellow-grey caste to it and the leaves are just starting to show signs of wrinkling. The rest of my phals are rather dark in color as my lighting situation is not optimum, so there's definitely something going on...

[WhiteRabbit]

When I have had fusarium, pbulbs started to rot, for no reason I could discern until I cut the rhizome and found that purple ring that indicates fusarium. Yours does not look like that, but like a wound (perhaps from mechanical damage, or something chewing on it). I'd treat the area with 3% hydrogen peroxide and cinnamon, and watch it - also check well for pests.

As to the Phals, I'd first check the roots.

[meliana]

The roots on the phal are nice and green, but you'd never know it from the leaves...

I'll treat the oncidium wound with peroxide and keep an eye on it. Thanks.

[Orchid Whisperer]

If only some of the Phal leaves are showing the yellow-gray, it might be time to cut them off. If possible, photos would help with a diagnosis.

[james mickelso]

Along with the peroxide I would paste cinnamon on it to help dry the wound off. It cauterizes the wound and dries it off. The phals lose the bottom leaves as it starts to grow new leaves. leaves are where phals store their load of starch and sugar for the next growth cycle.