What disease is this (on cattleya)?

[withoutid]

Hello,

I stopped by a local orchid nursery and found this really lovely catt (Lc. Irene Finney 'York'). After a careful look at the catt, I noticed some thing on it's leave but not sure what it is. I guess it's a fungus infection but may also be a virus. The first photo was under a leaf, the second one was on the surface of the same leaf. Anyway, I couldn't resist and take it home already. Please feel free to share your opinion

[Leafmite]

I would keep it isolated for a while from any other orchids that you own just to be on the safe side. That will give you a chance to see what is happening with your new Cattleya. It might be something as simple as being burned from the sun or, as you have suggested, a fungus.
I usually keep new orchids that are from certain vendors separate from the rest of my collection for a few months. I just tossed one of these a few days ago because it developed some signs that were very, very suspicious. If I had kept it with my other orchids, I would be panicking by now.

[withoutid]

Thank you, Leafmite. I'm pretty sure this is not a sunburn. I burnt many of my chids, especially catts, to make them bloom in the past ;-).
I just took a reference on the book "orchid pets and diseases" by AOS and felt it's very likely a Cercospora (fungus) infection. There are quite a few members in this family so I'm not sure the exact species. According to the book, "fungal leaf diseases are general cosmetic...When leaf spot becomes severe, use fungicide (systemic)". If it's true then, I can have relief now ^^

[Orchid Whisperer]

It looks pretty much like sunburn to me.

Keep an eye on it, keep it isolated for now, just in case. Try to see if the affected area is growing at all. If not, after several days, then I would say sunburn.

If it does show signs of growing/spreading, then I would say it is bacterial. It does not look fungal to me. It also does not look like any virus I have ever seen photos of.

[La Casa de las Orquideas]

It can be fungal... we always quarantine our new additions as a rule, but we also spray them with this:

Try it, it wont hurt:

MULTI PURPOSE SPRAY:

In a pint spray bottle, mix 2 tablespoons of powder cinnamon and 1 cup of rubbing alcohol. Shake well and let rest overnight. Filter the solution ti get rid of the cinnamon powder (a coffee filter works great), wash the bottle and return the solution to it. Add 2 tablespoons of liquid dish soap and fill the bottle with water.

We have it always at hand and we use it for everything! To disinfect cuts to roots or affected areas of the plant, when we add new plants to our collections as a preventive measure, to eliminate mild pests, bacterial infections and fungi. Works wonders!!

Hope it helps!!
**

Also, observe the damaged area and see if it changes color/grows. If so, cut the affected area with sterile scissors or cutter (use the spray for this also) to prevent the alleged desease from spreading.

[Orchid Whisperer]

L.C.d.l.O, that mixture might be OK on leaves and stems, but I would not be spraying it on roots! Cinnamon is too much of a desiccant.

This does not look like any fungus I am aware of that affects orchids. Probably sunburn, but if it is spreading, its bacterial. If it is bacterial, then yes, cutting out dead tissue is a good measure.