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.
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!
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.