Ringed spots on cattleya leaves

[Chatbud]

Does look like ORSV/CMV which is orchid AIDS.
The literature I read says there's no cure and the only recommendation would be to dispose the orchid.

[mooburr]

Thank you all for your input. I've decided to throw the plant out. I don't think it's worth the risk if it could be ORSV/CMV, which seems to be the general consensus. Just another reason to buy another orchid I'll keep an eye out for another chocolate drop.

[silken]

Originally Posted by mooburr

Thank you all for your input. I've decided to throw the plant out. I don't think it's worth the risk if it could be ORSV/CMV, which seems to be the general consensus. Just another reason to buy another orchid I'll keep an eye out for another chocolate drop.

At least that hybrid might not be too hard to find another one of. Good luck. It did look pretty sick whatever it was!

[Roland Brooks Cooke]

No, this is NOT a viral infection, even though it closely resembles one.

This is a relatively new disease, caused by bacteria. The agent has been identified as Acidovorax avenae, formerly known as Pseudomonas avenae. It appeared in Cattleyas in Brazil and elsewhere in 2009, and is spreading throughout orchid nurseries and collections sinceramente that year. As ofertas presente, I have not seen any official studies published about it, and so the following is personal experience. Lesions start as discolored pinpoints on young leaves and other growing tissue, and grow rapidly in concentric circles. Eventually, the whole leaf is destroyed. The infection is prevalent during hot summer months, disappearing during the cold season. It spreads rapidly throughout the greenhouse, and will compromise the whole season's new growths. It is NOT systemic, and affected plants will produce healthy leaves the following season if the infection is stopped. Control involves elimination of all affected partes (leaves and pseudobulbos, if affected) and application of bacteriocide. Casugamycin (Kasumin) os effective in stopping the spread of the disease throughout the Orchid collection, but applications must be done frequently (twice a month) during the summer.
Hope this info is useful to you.

[Orchid Whisperer]

Very old thread (???)

Acidovorax is hardly new. I have never seen it as ring spots like this.

[Roland Brooks Cooke]

No, it's not new. Pseudomonas is an old acquaintance of Phalaenopsis growers. What's new about this strain is that It doesn't attack Phalaenopsis, just Cattleyas, and causes these unsightly virus-like symptoms. I personally tested 5 affected plants for ORSV/CyMV, and all resulted negative. After applying Kasumin, the lesions stopped expanding and no more leaves were affected.

[estación seca]

Pseudomonas is a waterborne bacterium that will not spread well in low-humidity environments. It also prefers warm weather. Moving an infected plant to a cooler and drier area for treatment should help prevent spread. After removing infected tissue I would consider spraying green parts of the plant with hydrogen peroxide 3%, which will kill bacteria on the surface, but not inside the plant.

Pseudomonas acquire antibiotic resistance rapidly, so I would not treat repeatedly with just one antibiotic.