Black patterned spotting on leaf and subsequent yellowing on Phal. Mini Mark

[FranningtonBear]

Originally Posted by estación seca

I still think it might be cold damage. Consider putting a thermometer next to the side of the plant close to the window to see what the temperatures are.

I agree. I was gifted two Phal’s a couple of years ago, both with yellowing leaves just like yours. Previous owner told me the affected leaves had been near a north facing window. I haven’t experienced any further abnormal leaves since they arrived and were placed in a warmer location.

[cousky]

Update: Cut the first leaf before it yellowed all the way. The part around the stem is still green. The second leaf that had marks on it yellowed the same way. It yellowed and dried all the way down to where the leaf wraps around the stem, without affecting any other leaves or the stem. Tried to remove it, but had to cut it off as well. Orchid is still flowering and looks fine, other leaves look stable

Considering that the second affected leaf started rotting later than the first one, I assume it has something to do with the black marks. These marks appeared and remained static for more than 6 months. I don't believe it is cold damage (however, I do agree that it looks similar to it and it is a probability due to being near a window), since it happened on two leaves facing different directions and the other leaves are fine. Or perhaps it is cold damage on already damaged areas of the leaves, which resulted in yellow rot. But then again, the yellowing on the second leaf didn't start until after the first leaf was already removed.