Is this a virus on my Cattleya?

[Mirabelle]

I had an outbreak of black rot a few months ago. I was able to save some Catts but had to throw out quite a few.

This is a Blc Mme Roselyn - Reismann "Mendenhall". I lost a quadruple bud to black rot in September but the rest of the plant seemed to be surviving.

Last week a leaf turned yellow and black. I removed it. This week, another yellow leaf, and all the green leaves have a long black stripe down them.

What is this? Is it too late for the plant?

[orchid-man]

Hi Mirabelle.sorry to haer about the bud loss.To me it looks like the plant is going the same way.Its not a virus that I can assure you.To me it resembles frost damage,which I suffered badly from last winter.The plant can be treated with a good fungacide which will also cover bacteria,but the outlook is very bleak.If the plant survives it would be years before it will flower again.

[Mirabelle]

Orchid-Man, thanks for your help. This plant has been indoors since October. IT did see some temperatures down in the low 40's prior to coming in the house. Would that be considered frost damage to a Cattleya? Or perhaps I damanged it by messing with it out of desperation?

About 2 months ago the sheath in bud sheath turned jet black, and when I cut it off, it was slimy and smelly underneath. I did some trimming and scraping trying to get the black stuff off. There was also major root loss. It's now in s/h.

Here's another Catt - but this one has raised thick black spots on 2 leaves -- almost like callouses, and it has light black streaks. Is this the same problem?

This is a terrific forum -- I've been going through the postings for the past 3 hours. There is so much to learn from you experts!

[Korxi]

To me it all looks like fungus! I got the exact same as you described on pot. burana beauty and had to throw it out.. Could be caused by lack of air movement around your plants in these dark and cold months!
If you have all your plants huddled up together it might be good to spread them out a bit

Christian

[Brutal_Dreamer]

Any white stuff under the leaf? I think Christian is right about air movement and you could have some pest. Look under the dark leaf and see if there is dry white stuff. Sorry that you are having trouble.

Cheers,
BD

[Gin]

Sorry for the trouble
I have had the same on a few over the years . I think it is a systemic rot inside the plant don't know how it enters unless thru the top when the buds rotted out . When I cut one up there was a streak thru the center of to Pbulbs kind of yellowish looking . A sneaky miserable thing . Gin

[Mirabelle]

My catt is definitelyh dying if not already dead-- it's down to 2 leaves now - both with huge black swaths. I soaked it completely in Physan 20, and there was no trace of any pests. The other leaves turned yellow and the p-bulbs got soft so I cut them off. The roots are completely gone and there's white mold growing where roots used to be. It's a pathetic sight.

[Becky15349]

It sounds like its been eaten alive- I'm so sorry!!

[mohi]

Wow thats Awesome!... Cool!... (From a plant pathologist's point of view!)
One way to find out if its fungus:
Cut a small piece of the leave, rinse it for 10 mins under running water, rub with alcohol, put on PDA medium... thats 200 g potato (cooked), 15 g agar and 15 g dextrose... put them in a beacher and add water until it reaches 1 lit. put some in petri dishes and after sterilization, insert the prepared pieces under a laminar flow... I've done this 1000 times in our university... I study plant protection... If the black fungus grows and expands its micellium then you must use some fungicide... Good luck...

[ischel1]

If it's smelly I think it's most likely bacterial. Dump it!