First instance of black rot

[Nanook 2010]

Been growing for 3+ years...first instance of black rot

Sterilized cutting tool, cut out affected area, soaked plant with 70% isopropyl alcohol solution mixed with water

[WhiteRabbit]

good you acted quickly!

[james mickelso]

Cut off everything below the black rotted area, dust the cut liberally with cinnamon, and pot it in the smallest pot you can fit it into. Or wrap the roots in sphagnum moss and put it into an empty pot. Water it every other day. What you are trying to do is get the roots and what's left of this orchid to push another pbulb from the base of this. It will take time so be patient. Or if you want you can send it on it's way to the compost heap. Your choice. I have saved many orchids with black rot this way.

[Leafmite]

Increase calcium for cattleyas and plant them on top of medium so that only the roots grow down into the medium (you will probably need to stake it). I had a plague of this that took out most of my mature and nearly mature cattleyas and I have not had a case since I did quite a bit of research and discovered where I was going awry (planting too low, not enough calcium).
Don't put alcohol on the roots...kills them. Alcohol, however, really works well. I used it at full strength. I ended up saving two but one eventually was discarded while the other made an amazingly complete recovery. Good luck!

[Nanook 2010]

Don't put alcohol on roots.... But alcohol works very well.... Not quite sure I understand your advice

We'll see if it recovers.... I doused the entire plant with alcohol solution( and a few close by too)

[tucker85]

Unfortunately cattleyas are very susceptible to black rot and other fungus problems this time of year. I'm amazed that you went two years without experiencing any problems. I lose a few pseudobulbs to black rot every rainy season. I always cut the infected part off but it can still affect the plants overall growth for the season. Some years I've used Thiomyl (a systemic fungicide) every three weeks, starting in April. It seems to do the trick but often (like this year) I don't get around to using it. Good luck.

[Nanook 2010]

Tucker....
What about physan 20 every 2 weeks?

[Leafmite]

I doused everything but the roots with alcohol. The roots are sometimes sensitive to alcohol.

[james mickelso]

The fungus that causes black rot (I think it is more than just one) are always around. They are like cold viruses. It is when the plants are stressed that they succumb to it and develop symptoms. Plants are pretty good at taking care of themselves or they wouldn't be around. It's when they are cold or otherwise stressed that they get the diseases. Forget the area above the blackened part. What is important on this plant now is the area at the base of the former pbulb and the roots. Next seasons potential is what is important.

[Nanook 2010]

Looked like infection was spreading...

Trashed it