Sphagnum is god to mix in with the bark. it is antiseptic helps to keep the
injured orchide from geting attackt when it is down for the count.
Mattias
"Diana Kulaga" skrev i meddelandet
.net...
That's happened to me a few times. Could be overwatering, bacteria, or
fungus (that's what started mine). Don't forget to treat the plant before
you repot. A good dousing with peroxide, roots and all, and a dusting of
cinnamon works wonders.

Diana

"K Barrett" wrote in message
news:dBW%a.173640$Ho3.22673@sccrnsc03...
Yeah, some sort of rot. Best you can do is to cut the rhizome before the
rot
spreds to the other pseudobulbs. Oncidiums can tolerate not having many
back
bulbs. So if you can, cut the front 2-3 bulbs away from the infected
portion
and toss the infected portion out. Heck, even if you end up with only
one
healthy bulb its better than nothing. It may get set back by such heavy
surgery, but still its better than losing the plant. Oncidiums are
relatively tolerant as far as orchids go.

Make sure you repot in fresh medium. Medium should be chosen in
proportion
to the size of the roots. Oncidiums have fine roots, so a fine bark
should
be used. Use a new or clean pot so pathogens aren't transmitted from the
old
pot. The size of the pot should just hold whatever good roots remain,
even
if this makes the plant sort of top heavy. If it is top heavy after
repotting you can then slip the plant and its pot into a second larger
heavier pot (like a clay one) so it doesn't tip over. and so you don't
jostle it as it makes new roots and grows.

Whatever pseudobulbs you have left should be firmed up in the pot so the
plant doesn't move in the pot. You should be able to lift the pot by the
plant, it should be that firm in the medium and pot.

K Barrett

"west" wrote in message
...

It's sort of a tan brown. Starts at the base, gets about half way up
the bulb, and the bulb just falls off. New growth next to it goes
next,
in the same manner. The brown area smells just like a rotten Bearded
Iris root. Rancid. Mushy. I know if I don't get control of it soon,
I'll
lose the other five bulbs.

west