Very fine powder on base of two of my orchids

[meliana]

I just noticed something like a fine, off-white/ light brown powder on a phal and oncidium. It wipes off easily with my finger, and I tried to get a good picture of what was left. It's concentrated on the base and the tops of the roots, and so far is only appearing on one side. I repotted the phal a few days ago and didn't notice it before that, could it have hitched a ride on my potting mix? The oncidium is the next closest plant.

I couldn't seem to find reference to anything like this, does anyone have any idea what this could be and how to treat it? My resources right now are unfortunately limited to original listerine.

[meliana]

Forgot to upload the image...

[jemckinney]

Meliana, I logged on to ask this same question... I will add to your question if that is ok. I also have a white powder substance on one of my phals and I wonder what is the best measure to deal with the problem. First, should I isolate the phal like I already have? Second, what causes this white powder/fungus: too acidic or alkaline - too much or little lighting? Third, what treatment would be recommended?

I will also add that I moved my plants indoors and they are under lights. My orchids have been under the lights since mid October and most are thriving while a few are more dormant with the exception of this one phal that has the white powder. I usually water when the potting media is completely dry and I haven't fertilized in close to 2 months. Hopefully this question can be answered and I hope that it also helps Meliana.

[jeremyinsf]

jemckinney - you appear to have an outbreak of mealybug.

meliana - I can't tell what you mean in your picture. does it look the same as jemckinney's picture, before you wiped it off?

[meliana]

Jeremy-- no, it's not at all like what I have. Unfortunately that was the best picture I could get, and you can see it a tiny, tiny bit at the very base of the plant, but I agree it's rather poor quality.

The powder is in a very even and thin layer, almost like the plant just got dusty or something, but it's not in places dust would normally accumulate. It also does not appear on any of the leaves (or hasn't yet), just at the base and roots. On the oncidium, it's on the part of the pseudobulb closest to the potting medium. Hope that helps!