Cattleya percivaliana with black pseudobulb

[orchid94070]

I was hoping this rootless seedling would recover. What causes the black pseudobulb? Should I try to save it or it's beyond this world?

[estación seca]

Is it still firm? If so it might not be fatal.

It is dehydrated. It hasn't been getting enough water. What happened to the roots?

[orchid94070]

The black part feels a little softer, the green upper part feels firm. The second photo shows a second (smaller) pseudobulb that looks fine.

I didn't water this plant properly (too much water). When I checked the roots, most of the roots have rotted away, so I cut the dead roots and try to let the plant recover (and sprout new roots?).

Do you think it's a fungal/bacterial infection? Black rot?

[estación seca]

I don't know if it will recover. Black pseudobulbs on Cattleya seedlings are more often caused by underwatering than overwatering. I wouldn't cut roots off seedlings, no matter how the roots looked. Cattleya seedlings are very easy to kill with improper care.

What was it potted in? How did you water it?

[orchid94070]

Thank you so much! I will be careful not to cut roots in the future. It was on sphagnum moss but I soaked the moss and it was generally too wet. I will try to put a humidity dome thing around the seedling. I guess my only hope it's for it to sprout a new pseudobulb or root...) Thanks again!

[estación seca]

They try mightily to make new growth. You may only get one chance. The higher the humidity, the better. When tempratures are warm ( > 80 F / 35C) Catt seedlings usually don't mind fairly wet sphagnum. In fact, it is better wet than drying out.

Edit - scale insects can cause this, too. Do you see any white fuzz on the plant? Maybe down in the crevice at the top of the leaf?

[SouthPark]

ES is right about seedlings. They can certainly grow very well in sphagnum when given nice temperatures, and controlled amount of moisture in the sphagnum.

As for the black coloured pseudobulb - hard to say what it is. If it is soft, then that particular bulb might not make it. But at least the other growths are ok. Maybe copper spray on leaves and stems of all bulbs might be a good idea to start with. And also could provide some a mag-cal supplement every once in a while too ----- just in case.

Do you have some natural air flow in the growing area? And has it ever been exposed to relatively low temperature?

[orchid94070]

Thank you both for your responses! I have/had scale issues with other orchids, but this cattleya doesn't have the white fuzz. I live in Northern California, so it's dry here. I started opening the window a little at night, so the room temperature was maybe about 17-18 oC (mid 60s). It is not too warm during the day either. I also managed to burn some leaves on other orchids when I try to get them warmer in direct sun...

I put a cake dome over the plant. Hope it survives! And put a tray of warm water next to it. There are moisture droplets on the leaves now, hope that's ok...

[orchid94070]

Here's a photo of the current rescue station

[orchid94070]

And yes, I ordered physan 20 (is that an ok-substitute for a copper containing spray?), which will arrive in 5 days' time. I read somewhere that copper containing spray is not good for dendrobium? I also used imidacloprid for the scale problem (making a 1.5% solution and dunking the plants in the solution).

Last year I took a plant that was infested with the hard (shell like) scales onto the deck, and a ladybug laid a bunch of eggs on the plant. I didn't realize that was ladybug eggs, and I cut off the branch and tossed it away. Only later did I realize what I had done. I'm not sure if ladybugs will return again this year, so I am turning to chemical means (and feel bad about that).