Issue with spotting on leaves spreading!

[NKOrchid]

Hello!

I posted here a while ago describing an issue with my dendrobium. It had some black spots and I was unsure whether or not they were spreading.
A couple of months later now I can say that they're definitely spreading and I'm scared for my orchids lives. The spots have gotten way worse on the dendrobium and they spread so much I cut down two canes. Now it has four canes left with not so many black spots on, but lots of yellow, dark green and even grey-ish spots! I have no clue what this is. Mites? Fungus?
I've come to terms with the fact that the dendrobium probably will die, but the condition has spread to other plants! As soon as I noticed the spotting a few months ago I took it away from the rest of my collection, but that was apparently too late.
I have another dendrobium who has the black spots now and my beloved masdevallia seems to be suffering too! I'm afraid this will spread or already has spread to all of the orchids and it's just a matter of time before they will all suffer like the dendrobium.
Please help! Any suggestions on what's wrong and what to do will be so appreciated. Thanks!

Dendrobium with grey-ish spots:
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Dendrobium with dark green spots:
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Dendrobium with yellow spots:
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The entire plant that seems to be dying:
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My poor masdevallia:
Imgur: The most awesome images on the Internet

[silken]

http://www.staugorchidsociety.org/PD...ySueBottom.pdf

If you haven't looked at the St. Augustine site, here is the link. It is an excellent source of photos to identify what your plants have and how to treat them.

Yours could be bacterial brown spot. Have you treated them with a good bactericide? If not, I would be doing so soon. The spot on the Masdie does look similar to the other spots.

Hopefully others will chime in too. good luck.

[NKOrchid]

Thank you for the link! Definitely helpful.
When looking for a bactericide/pesticide is there anything in particular I should be looking for? Does it have to be specifically for orchids?
Can all types of orchids be treated with the same bactericide/pesticide?
Does it have any negative effect on the plants and can I spray plants that don't seem affected? I'm just thinking that it would be the easiest to get rid of it all to spray all plants.

[Selmo]

Try Hydrogen Peroxide

[silken]

Physan 20 is a fairly safe treatment that seems to be used by quite a few orchid growers. I won't say it is totally harmless to every orchid because you could have an exception that doesn't like it. But if used at the correct dosage most orchids should be fine with it.

That link I gave you also has suggestions of what is best to treat each type of problem. I have used Cleary's systemic fungicide to treat plants with black spots and it never hurt a plant and did seem to help also.

I think your issue could be bacterial, but it is rally hard to know for sure.

[NKOrchid]

I will try to get both Physan and hydrogen peroxide. Should I just go ahead and spray all my plants?

[silken]

Originally Posted by NKOrchid

I will try to get both Physan and hydrogen peroxide. Should I just go ahead and spray all my plants?

I would probably only do the few worse ones first and make sure they survive. I don't like to tell someone yes, go ahead and spray everything. It is your risk. But I likely would as it seems to be spreading.

[NKOrchid]

Well, I'd never blame you if they all ended up dying. I'm the one doing the spraying! I think I will go ahead and spray the ones I'm not too attached to. Thanks for the help!

[Cdmcmonigle]

Repotme.com has very good instructions on using physan 20 under the description of the product.