Tell me about black rot

[Rothrock42]

I'm not sure if I have black rot or not.

I have a Stanhopea warscewiczii. It has a few pseudobulbs and leaves. A couple of weeks ago I moved it to a bit higher light levels and two of the leaves turned yellow and fell off fairly quickly. I assumed it was because of the change in light and that they are the leaves that came from the nursery more than a year ago. I wasn't too worried because it still had two larger healthier leaves and was growing a third.

Then I noticed that the old pbulb had changed to solid black color. I was thinking that it was just from the higher light, but now I'm not sure. It is way darker black than the usual "high light purple."

Some of the other bulbs have a bit of dark mark on them, but they seem fine and it hasn't progressed in a couple of weeks.

I pressed on the bulbs and they are firm and not squishy at all. That is why I hadn't quite put it all together. Isn't black rot supposed to be squishy and, well, rotten?

[estación seca]

These plants often drop many older leaves each year. Catasetum relatives usually are deciduous. I have noticed dying Stanhopea pseudobulbs often turn dark, but remain firm.

Plants affected with black rot usually develop mushy pseudobulb bases.

I suspect your plant is losing older growths; why I cannot say. During the growing season I think this usually would happen due to a too-small root system or not enough water.

[Rothrock42]

Thank you ES. So without the squish it is likely not black rot? That is good news. I'll keep an eye on it. But it hasn't spread or gone squishy in a couple of weeks.

I think it could be the change in light and air that is shocking it a bit. It is the smallest least established of my 5 stanhopeas. I'll keep an optimistic eye out, but I'm feeling a lot better now.

[Roberta]

Originally Posted by Rothrock42

Thank you ES. So without the squish it is likely not black rot? That is good news. I'll keep an eye on it. But it hasn't spread or gone squishy in a couple of weeks.

I think it could be the change in light and air that is shocking it a bit. It is the smallest least established of my 5 stanhopeas. I'll keep an optimistic eye out, but I'm feeling a lot better now.

You might try just increasing watering... I have a bunch of Stanhopeas, that in spite of my best efforts, lost most of their leaves. I just put in an RO unit, moved them to where they get the RO water... and they are also just plain getting more water. New leaves suddenly poking out from all of them. So better water might have helped, but I think it was more the case of more shade and more water that kick-started them.