yellow pigment on roots

[K.Veren]

Hi everyone, I have a question about a root on my phal. I think it's an aerial root, even thought it looks more like the other roots in the soil rather than the aerial roots on another one of my plants.
I noticed a few weeks ago that it was starting to turn a bright shade of yellow, but aside from that it looks really healthy.
I also noticed that I could wash the yellow off completely by using a spray bottle to mist the root and the root returns to its normal pale green color. when the condensation drips off the root, it is a bright neon yellow.

any idea what this might be? is my plant dying? is it sick? or is it just some sort of natural mineral buildup/metabolite? should I keep trying to wash the yellow off the root or not?

thanks!

[King_of_orchid_growing:)]

Powder mildew perhaps? At least that's what it sounds like. If you have a pic, it'd be better diagnosed.

If it's powder mildew I'd try to get rid of it using Phyton 27, which happens to be safe on all surfaces of the plant. Phyton 27 is a bactericide and fungicide. It consists largely of copper sulfate.