Black marks on Phalaenopsis

[Aleksa]

I bought this phal few weeks ago in bloom. I choose it very carefully and it had very green, hard, and healthy leaves. But now, I noticed that those marks have started to appear on bottom leaves, and they softened also. Leaves on top are still healthy. What is this? I suspect on bacterial infection but I hope it isn't because I had some bad experience with bacteria.

I cutted off the flower stalk and repoted plant. Roots are in excellent condition and top 3 leafs are also very healthy. Should I cut off these infected leafs? I know that cutting phal's foliage is not recomended but this looks to be something bad.

[digitalgate]

look like mechanical damage. cut off if it get worsen. If it stay brown and did not spread
then it is still mechanical damage. The plant can handle and bloom with this damage.

[mayres]

I'd keep a VERY close eye on that - if you see it start to creep towards the crown of the plant I'd remove it immediately. No use to risk the health of the entire plant.

[Aleksa]

Originally Posted by mayres

I'd keep a VERY close eye on that - if you see it start to creep towards the crown of the plant I'd remove it immediately. No use to risk the health of the entire plant.

This thing is spreading. I'm not a phal novice, I have some experience with diseases. I'm sure that this is not a mechanical damage. I will cut off all infected leafs. I removed flower stalk, It is too risky. Crown is still healthy.

[11Orchid126]

You might consider pouring some full strength 3% hydrogen peroxide in the crown and the axils of the leaves. Leave it there for a while then pour it off. Do this again in a few more days. This may stop whatever it is from spreading.

[Cynthia, Prescott, AZ]

You should probably look for mites to be on the safe side.
Checking For Mites

[Aleksa]

Thanks Cynthia, your advice is very useful. I think that there I had bacterial infection... I hope I don't have it anymore because i cuted off the infected leafs. But sometimes happens that infection starts to spread again, even cinnamon doesn't helps. I'm affraid of those infections because there is virtually no cure for them.

[Cynthia, Prescott, AZ]

Well, it doesn't look like a bacterial problem to me. Bacterial infections have a clear or watery character. Yours may be from some kind of bug, fungus, OR, cold water on the leaves. Watch out for cold water. I had some damage from cold water, then moved my RO water tank beside the GH, opened the wall, and insulated the tank/GH area. Then recently added the largest aquarium heater they make. Works great. After that, the only damage I saw on my Phal leaves I have attributed to neem oil use.