Phalaenopsis - Black spot on leaf
 

One of my phals has a black spot on just one of its leaves. This developed more than a year ago now and does not seem to effect the overall health of the plant. Many new roots have developed, a new leaf has grown over the summer, a second leaf developing now and a new spike is beginning. Also, a node on the old spike that I just cut is swelling and it looks like it may send out new growth. My question: what is the cause of the black spot and should I cut that leaf off the plant or leave it alone?

My first time posting a photo so hoping that I did it correctly so you can see it.

I'm new so I may not know what I'm talking about. One of my phals has a similar lesion. I'm suspecting some kind of past fungal infection. It's been about a year now and the lesion hasn't spread and all the new leaves are fine. The diseased leaf is finally starting to yellow so hopefully it'll drop and the plant will be blemish free. I'm leaving the leaf on mine sine it still seems functional.

Due to either past bacterial infection, or past sunburn (or similar environmental damage).

If it has not grown in a year, leaving it alone will not harm the plant. The remainder of the leaf is green and is still photosynthesizing, therefore is feeding the plant. I would leave it alone.

I'm in total agreement.

As long as it's not spreading, and the leaf is still green, it is contributing to the wellbeing of the plant.

Wait, and let the plant decide when it's ready to drop it.