Pseudobulb rot in Pot. Congaree Mendenhall?

[Chunky_Punk]

I hoping some of you can help with this issue, one of the latest showcasing my inexperience.

I purchased this plant, identified as Pot. Congaree Mendenhall and it appeared to be in good shape. Last week I noticed what appeared to be a discolored blotch on one of the pseudobulbs that I'm fairly certain wasn't there when I bought the plant. I kept an eye on it for a day or so, began to panic when I convinced myself the blotch felt squishier than the surrounding healthy looking portions of the bulb and the other bulbs.

Paranoid, I pulled the plant out of the pot and found nearly all the roots were dessicated. Why I'm not sure. I don't believe I overwatered. At the time I pulled the plant the roots and medium were bone dry, but I realize they could have died from overwatering at some earlier point and just dried out...

Ultimately, I panicked and cut off the suspect pseudobulb. I then cut into it to examine the splotch and discovered that it didn't appear, to me at least, to have existed in the bulb at any real depth. Almost seemed cosmetic, if that makes sense. I will try to include pics in the post below which will be my 5th...Thanks very much for any thoughts on this. Did I do the right thing or overreact, and how far does this set my plant back?

[Chunky_Punk]

Here are some pics (hopefully)

[Mandy2705]

I think you did the right thing, it might not have spread and then it might have. Why take the chance? You did the right thing in my opinion

[estación seca]

My observation has been that, during warm weather, underwatered Cattleyas can get spots like that.

[Orchid Whisperer]

Chunky:

When you say dessicated, do you mean instead that they felt papery, rather than firm?

The roots of orchids have a tough string-like center that is the true root, surrounded by a thick layer of cells called velamen. The velamen quickly absorbs, and then holds, water and nutrients to supply to the roots. Orchids are adapted to absorb their water quickly through this velamen; it is an adaptation that these tree-dwelling plants have, enabling them to use rainfall that may come during only short rain events (intense showers that last only a few minutes are common in many tropical areas).

That velamen layer in Cattleya-type orchids can rot easily if it never has a chance to dry out. If the velamen rots, it becomes soft rather than firm, and if it dries out after it rots, it feels dry and papery. Often the root (string) inside the velamen rots as well.

You can think of it like this - the velamen is sort of like one of those disposable diapers. Its job is to absorb water. With a baby, you periodically have to change the diaper to keep the baby dry & happy. With the velamen, allowing it to dry in between watering is analogous to changing the diaper. With the baby, if you constantly leave the wet diaper on, you will end up with diaper rash and a miserable baby (and a Cattleya type whose roots never dry will develop rot and also will suffer).

You did the right thing to cut off this pseduobulb; better safe than sorry. However, the dark areas may be just excess sun or some similar factor, and might not be rot. I think the wrinkled pseudobulbs may be because of the lack of healthy roots.

If you have not already done so, re-pot into new, coarse orchid medium (bark or something similar). Let the plant recover in a shady area, it should get new roots when the next new growth (leaf and pseudobulb) approaches maturity.

Losing one pseudobulb on a plant that has many other pseudobulbs should not set the plant back too much.

[Chunky_Punk]

Thank you both for your insights. Yes, by desiccated I mean papery and bone dry. I removed all those roots and repotted in a mix of bark, perlite, charcoal, and some broken up wine corks.

There already was some healthy new root growth beginning, so I made sure the plant is stable in the pot with a rhizome clip and put it in a shadier spot than it had been, under a tree. I've been misting it with some Superthrive but have tried to keep it on the drier side for a bit...

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