Hello, I've recently noticed these black lines on my mini cattleya. I don't know how long they've been there, but my other orchids haven't shown similar symptoms.
Lesions like that are common. If they're firm and don't spread they're nothing to worry about. I think it represents old damage from many potential causes like underwatering, excessive light, heat, scrapes and scratches.
Soft spreading lesions are likely to be fungal or bacterial infection.
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