AHH!! I looked between two leaves on one of my phals today and saw this! The leaf that is on the top only has it on its underside and the leaf below that only has it on its top. It is on the same spot on both leaves, in a sense that when I am not holding the top leaf up the "infected areas" touch each other. Other than this the plant seems healthy.
Hard to say what it is. Maybe someone else can help. But you could put some Physan on it if you have it. Cinnamon is another option. Was it outside? Possibly an insect was on it?
I've had this happen on rare occasions to a couple of my phals that are kept out during the spring summer and fall and spend the winter in the sunroom. It seems that outside of being cosmetically not pleasing to look at the leaves that have had it continue to grow and the spots stay the same. I wish I had an answer but the plants that this happened to are 6 years old and outside of the blemish on the leaves produce flowers every year.
Almost looks like something has been munching on the leaves, like a small snail for example. Keep an eye on it, as long as it doesn't spread or get worse I don't think there's something to worry about.
__________________ Camille
Completely orchid obsessed and loving every minute of it....
Great! Thanks, other than that the plant seems healthy. It has recently grown a new leaf and is working on a new spike. Other than the cosmetic aspect I am not worried about the plant and you can only see the spots when you lift up the leaf.