Dendrobium Blight?

[ampaud]

Hello everyone! I need a little help.

Every time I have purchased a Dendrobium, they have always looked great, nice and green, pseudobulbs plump, and no signs of pests. I always check existing blooms (if there are any) for streaking so as not to bring viruses into my home.

However, every time I bring them home, they seem to be affected by the same disease. I have now lived in two homes and make sure to keep my plants quarantined if they are newcomers. The first time this happened, I had acquired a Little Atro Dendrobium that was just beautiful and had lots of blooms - and the leaves just started showing yellow areas and spots. The spots quickly spread from leaf to leaf, and eventually killed the plant, as well as the Bruce Gordon that I stupidly kept nearby at the time.

Now, I am smarter and generally a better cultivator, so I was brave when I picked this one up last week. She was gorgeous, had nice, tall flower spikes and everything looked ok, her leaves just needed to be washed. And what do you know - - but the spots are here! This time I was wise enough to take a picture.

What is this?? Is there any way to identify it on a plant before I purchase it? Is there anything I can do to stop it from spreading? I am including pics of the flowers, the most recently impacted leaf top and bottom, and the leaf above it (the infected leaf looked like this healthy leaf just a day ago, then last night I saw the spots!)

Thank you!!

[Dollythehun]

I don't have a clue but, I'll be interested to find out with you.

[estación seca]

How warm is the growing area? How are you watering?

This kind of Dendrobium does not like cool temperatures, and does not like drying out for very long. The leaves with spots look wrinkled. When Den phalaenopsis types don't get enough water, their leaves can die like this. The fungal spots are attacks on weakened leaves.

[ampaud]

I will try to put her in a warmer spot if that is the case - she should do well with my paphs upstairs then. Fingers crossed!

[Selmo]

Dendrobiums don't like it when their environments are changed. Many plants drop their leaves when stressed by changes in their surroundings. What ever the spots are,where there unseen and as the plant stressed it became visible. The yellowing of the leaves is normal acclamation to your environment. As the growing conditions at the nursery are different than yours. The spots look odd because of the darker green halo around the sunken black spot. Usually the halo is yellow or lighter green. Darker green would suggest the presence of nitrogen. Either the fungus/bacteria are producing nitrogen as they multiply or this could be from fertilizer water droplets setting on the leaves to long causing burn spots, like dog spots in the lawn. Just a guess, as you say this spreads from leaf to leaf and to a different plant. If this is fungal/bacterial it would be spread by splashing water. I just don't know about pseudomonas or one of the leaf fungi having darker green halos. Any way, I would remove the infected leaves as soon as possible and isolate the plant from others. Give it more light and air movement, water from below minimizing leaf wetness.

[camille1585]

My experience with the Dens I've had (and killed until recently!) is that they are very prone to spots of all sorts and yellowing if the air movement isn't sufficient and they are left too dry between waterings. Ever since I improved those 2 aspects my Dens have stayed healthy, and alive!

[estación seca]

Little Atro is a Latouria group Dendrobium. They can't dry out for any length of time, especially tiny plants. If they dry out entire growths quickly turn yellow and die.