Dendrobium Nobile, Yellowing Leaves with Black Blodges
 

Please can anyone tell me what is ailing this Dendrobium I am loking after which I think is a Dendrobium nobile? In bloom it has masses of white flowers up the stem and when I was given it to look after there was only the one thick central stem. One leaf has yellowed and has black blodges on it. Another leaf is starting to go yellow and has a small black spot on it. To be on the safe side I have moved it away from my other orchids but it is in the same room. I hope there is no danger of the ailment spreading to the other orchids in that room.
Thank you for helping.

It may just be shedding foliage - nobile types are deciduous, dropping leaves from matured canes this time of year.

I hope other members will be chiming in with their opinions, as I cannot be positive that's all that's going on.

Like White Rabbit says-Nobile type Dendrobiums drop their leaves in the fall when mature.Check up on their culture and be sure you are not using any fertilizer containing nitrogen and give it cool nights and we hope you will get flowers!

Mine are dropping their leaves also at this time, getting ready for the winter rest!

Mine too.

Thank you everyone for answering. I have put it out on my glazed balcony where I try to keep a temperature of 10 C until 1 December because I have tomatoes there. I hope that is cool enough. After my tomatoes are finished I can let my balcony get cooler.