Brassia with rotting pseudobulb?

[VeoVerde]

Hi guys,

I was gifted a very small Brassia Rising Star a month or so ago. Either when I recieved it or shortly after (I thought I inspected well but now not sure), the smallest pseudobulb had begun to discolour. Now the leaf on top seems to be dead.

I'm guessing that being the smallest, it's the oldest bulb, but I'm not sure? If it is, I suppose the loss of it wouldn't be catastrophic, but any ideas on what it is, whether it's likely to spread to the healthy pseudobulbs, and what I can do to help it would be very welcome!

Attached are photos of the browning progress (worst is the most recent). We're in winter here in Sydney, Australia, but it hasn't been so cold. the plant receives bright morning light through a window on the opposite side of the room, and medium shade from about 10:30am onwards. It's in a tiny pot, so I water maybe twice a week, when I feel the pot lighter (and dryer).

Thanks for any thoughts!!

[fishmom]

It's good that the browning is proceeding from top to bottom. You still have some green left on that bulb, so you can cut it off with a razor blade, all the way to the green part, and dust it with cinnamon. If it were mine, that is what I'd do. I wouldn't want that browning to reach the base of the plant.

[gngrhill]

I agree with fishmom. I would cut that thing off before it spreads down any farther. Remember sterile blade.

[estación seca]

Seedlings often drop the oldest growths when they move from a humid seedling greenhouse to a new, less-humid spot.

[VeoVerde]

Thanks for the advice everyone! I've cut it below the brown and dusted with cinnamon. Thanks fishmom for the suggestion!