Yellow spot getting bigger by the day
 

I have a huge leave on a Phal. that started a few days
ago with a small dot on the leave and everyday
it grows. It is round in size and today it is about the size of a silver dollar. The area is yellow and the leave feels mushy.
I put some ground cinnamon on the area yesterday, but looking at it today, it has grown past the area I treated.
I'm new to the Orchid world. I've only had these plants
for about 2 1/2 weeks. At first I thought it might be
stress, but now I'm calling for the experts (you) for
help.

John

Without a picture its hard to say. I don't consider myself a "pro" but I usually have good luck with "phals". If it was me I'd monitor it closely and make sure it doesn't spread. If all the other leaves are healthy I wouldn't be overly concerned. Hopefully one of the many experts on this site will help you with better info.

If it is growing it is probably fusarium fungus.

Cut it off at a point past the growth so that the cut shows good healthy color.

If the fungus gets into the stem and roots the plant will die.

It is a very common fungus, it spreads easily by hand or even splashing water. Be careful when working on a plant like this to sterilize your instruments (bleach is sufficient) and wash your hands.

Ok, I did surgery. I think that was the right call, because I think it was going to spread. My other leaves and plants look fine. What can I do to insure further problems. I've read where spraying
the plant with Listerine will help.