Ascocentrum sp. Black Spots - Phyllosticta?

[gdupont]

Hi, everyone,

I just got this orchid yesterday. I've long been looking for Ascocentrum curvifolium, and the seller said he's quite sure this is one, even though it was mislabelled as miniatum. Anyway, I've noticed some black spots on it, and a blackish powder on a few of the leaves, which rubs off easily with a wet paper towel. One of the leaf tips has died and theres a weird thing on it. There are images below of all of these. There's also some black on the hanging basket. Does this look like phyllosticta? What should I do? Right now it's separated from all my other orchids... So bummed. I finally found Ascocentrum curvifolium and now it looks like it has some fungal problem

Thanks.

https://flic.kr/s/aHskDHuUc7

[Leafmite]

Are the spots remaining the same or increasing in number/size? If they are increasing in any way, it might be worth treating. If the spots remain unchanging, the spots just might be from the sun or other damage that isn't too concerning. To be on the safe side, I often will wipe everything but the roots with Isopropyl alcohol to disinfect. If you get any alcohol on the roots, rinse off immediate as it can damage them.

[gdupont]

Originally Posted by Leafmite

Are the spots remaining the same or increasing in number/size? If they are increasing in any way, it might be worth treating. If the spots remain unchanging, the spots just might be from the sun or other damage that isn't too concerning. To be on the safe side, I often will wipe everything but the roots with Isopropyl alcohol to disinfect. If you get any alcohol on the roots, rinse off immediate as it can damage them.

I just got it yesterday, so I'm not sure about size. I know some of the spots are a little sunken. Should I cut off the tip of that leaf thats all brown with the weird goldenish colored stuff? I'll try Isopropyl, thanks for the suggestion! Should I dilute it with water first?


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[Leafmite]

You probably don't need to cut anything as it seems dry and harmless. If you think it unsightly, you could trim it a bit.

I use the alcohol straight. It looks quite healthy, actually, so I do not think you need to worry too much.

[Orchid Whisperer]

Some of those spots look diamond-shaped which is common with Phyllosticta. It does not look too bad.

Treat with a fungicide, see recommended ones at St. Augustine Orchid Society - North Florida Orchid Growing. I also find that if you provide calcium to the plant, you will have more disease-resistant plants, including resistance to Phyllosticta.

[Ray]

Frankly, that looks more like mechanical damage to me. Nothing to be concerned about.

[gdupont]

Originally Posted by Ray

Frankly, that looks more like mechanical damage to me. Nothing to be concerned about.

Interesting, thanks! What exactly do you mean by mechanical damage in this case?


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[estación seca]

Mechanical damage can be bumping into things nearby, scraping on something sharp, bending a leaf too far, dropping something on it.