Did I Get an Orchid With a Fungal Infection?

[LunchBox]

Hey all,

Picked up a Bnfd. Gilded Tower 'Mystic Maze' yesterday from a local grower. Some of the leaves have black spots on them, and two of the leaves have turned yellow around the black spots. The grower suggested this particular plant to me, so I figured it was perhaps some burn from being too close to light, but I did a bit of research and now I'm concerned. Is this a fungus that could spread to my soon-to-arrive orchids? Help!

Pictures:

[zainal abidin]

I'm thinking is fungal if I were you I will cut the affected leaves is common for the soft leaf. The rest of the leaves looks better and you can spray with fungicide.

[cakedaddy]

Yeah...it's likely fungal. Oncidium alliance plants are very susceptible to "black spots" fungus. They need lots of air movement. I use a fungicide on mine regularly.
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[LunchBox]

Crud. Thanks for the quick responses guys.

It’s about to bloom - do I wait until afterward to cut the leaves?

And what fungicide should I use? How quarantined from my other plants should this be? I’m in an apartment so it could be kinda tough...any ideas?

---------- Post Merged at 11:36 AM ----------

Crud. Thanks for the quick responses guys.

It’s about to bloom - do I wait until afterward to cut the leaves?

And what fungicide should I use? How quarantined from my other plants should this be? I’m in an apartment so it could be kinda tough...any ideas?

And while I'm at it...just about every leaf on the plant is showing some amount of these spots. If I cut them all off, It may just have 2 leaves. Should I just return the thing? I'm really disappointed that they'd sell me the orchid like this.

[jsehorn]

I wouldn't cut anything. Treat it with fungicide and make sure there's plenty of air movement first. That should take care of it. If it continues to spread even after that, then you might considering removing some of the affected leaves, but I'd save that for last resort.

[raybark]

Using Sue Bottom's guide to orchid pests and diseases at the Saint Augustine Orchid Society website, I'd say it was a pseudomonas bacterial infection.

I highly recommend folks download and keep a local copy of Sue's Guide

[LunchBox]

Using Sue Bottom's guide to orchid pests and diseases at the Saint Augustine Orchid Society website, I'd say it was a pseudomonas bacterial infection.

That's a great guide, thanks.

Does it change anyone's opinion that it's an oncidium? I posted in another forum and the response there was, "those spots always happen to oncidiums unless they're in perfect conditions, it's not fungal, and it is unlikely to spread to your other plants." Is there a test or any way to confirm?

[jsehorn]

Oncidiums, with their soft, thin leaves, are especially susceptible to various things which cause spotting on the leaves. I don't think the spots on your leaves are the blacks spots which appear in high light. They are too large and irregular. I do think it is the result of some type of infection, but I don't think you need to worry too much about it, because I think with proper culture, the problem will resolve naturally. The spots won't go away, but I don't think it will spread aggressively. I think treating it with a bactericide or fungicide would be a good thing to do just to make sure, but I don't think it is strictly necessary at this point. If you choose to do this, I think Physan 20 would be a good choice. It's a good idea to keep that on hand, because it is useful in a variety of situations. If you don't have that and don't want to buy it, treating the leaves with hydrogen peroxide might be helpful. It is true, however, that Oncidiums and their relatives just tend to have spotty leaves, and I don't think you need to be terribly worried.

[LunchBox]

Oncidiums, with their soft, thin leaves, are especially susceptible to various things which cause spotting on the leaves. I don't think the spots on your leaves are the blacks spots which appear in high light. They are too large and irregular. I do think it is the result of some type of infection, but I don't think you need to worry too much about it, because I think with proper culture, the problem will resolve naturally. The spots won't go away, but I don't think it will spread aggressively. I think treating it with a bactericide or fungicide would be a good thing to do just to make sure, but I don't think it is strictly necessary at this point. If you choose to do this, I think Physan 20 would be a good choice. It's a good idea to keep that on hand, because it is useful in a variety of situations. If you don't have that and don't want to buy it, treating the leaves with hydrogen peroxide might be helpful. It is true, however, that Oncidiums and their relatives just tend to have spotty leaves, and I don't think you need to be terribly worried.

Makes sense. Thanks for the input. I’ve got a bottle of Physan 20 on the way, and I’ll be taking your advice. Very much appreciated.

[Mike H]

it's now a year later LunchBox, how's that Oncidium doing today?

---------- Post Merged at 11:29 PM ----------

Using Sue Bottom's guide to orchid pests and diseases at the Saint Augustine Orchid Society website, I'd say it was a pseudomonas bacterial infection.

I highly recommend folks download and keep a local copy of Sue's Guide

Great resource Ray, just found this thread and downloaded Sue's Guide immediately.