Adding redwood chips/fibers to bark based mixes goes a long way to stopping
snow mold. If you follow Ray's recommendations and repot with a mix
containing 5 -10 % redwood you should not see the nasty again.

Pat

"Wendy7" wrote in message
...
My Oncidium Twinkle 'Red Fantasy' seemed to be struggling then I noticed
the
white
stuff through the clear plastic pot.
To be cont. . . . . . . . .