Brassavola seedling leaves got blackish lines along midrib

[Roberta]

I think now just warm and dry.

[sweta]

Yes it is warm and dry but do you think its erwinia or just discoloration due to stress? Do I need to treat it with physan?

[Roberta]

I think just stress. ES may have further thoughts on the subject, but I would not jump to more treatment.

[sweta]

thanks Roberta

[estación seca]

I am almost 100% certain it is not Erwinia. Erwinia in orchids is a bacterial disease of hot, humid and very stagnant air. Think 90 degrees, 99% humidity and almost no air circulation. Cattleyas, especially Brassavola, are not very susceptible to it.

This is likely damage caused by water entering holes made by the scale. Some of the leaf may die. Don't cut it off; let it develop its own demarcation line. It was a severe scale infestation and the plant still may not survive.

I would unpot this plant, let it dry for a few days, and pot it again. As I mentioned earlier, keeping a sick Brassavola at a maximum of 70 degrees is a problem.

I personally would never use acephate, nor other organophosphate insecticides, inside a home. It is supposedly less toxic to mammals than to invertebrates, but long-term effects of low doses have not been studied. Plants are not worth harming yourself. I don't even know if it's approved for use on orchids.

[sweta]

Glad that its not erwinia, seemed like water soaked areas on the leaf thats why I was a bit worried. Did you mean that it may not survive because of the scale infestation or is there a chance for it to survive? Btw I havent actually used Acephate on this seedling since I got it, in fact I havent used any insecticides on it. I just soaked the seedling in water with little bit of dish soap to form bubbles and then let it dry and repotted it. I did order for imidacloprid granules which I got just today but I havent still used them on the seedling yet. So do I need to remove seedling from the media and just let it dry, wont the roots die?