I use the same Physan treatment on my bark, so I doubt that's the problem. I
have heard of some bark being treated with herbicide to enhance the value as
a mulch to keep down the weeds. I don't know this to be a fact but certainly
sounds like it could be a possibility. There have also been accidental
spills of pesticide on other products. I'd recommend repotting in new bark,
CHC + sponge rock, or what ever your choice may be, but do it now before the
pbulbs lose all their vitality and you lose your collection. I've had shoots
come from rootless, yellow bbulbs but I hate to tell you how long it takes
to get blooming size plants again, but you probably already know that. Best
of luck in the chore ahead.
Gary
"TRAINMAN9" wrote in message
...
I repotted my greenhouse back in September. This is an annual event unless
a
particular plant outgrows it's pot. Most of the plants potted in the fine
bark
mixture wether paphs, cattleya seedlings or other types that like smaller
media
seem to be doing fine.

Most of the plants potted in medium bark mix are doing terrible. They
start new
roots for the most part and they seem to die off when they touch the bark.
A
number of plants have not even made any new roots at all. In fact a number
of
the mature plant with pseudobulbs have shrunken (this is common when
repotting
mature catts but they usually recover).

I treated the bark with a Physan and water mixture by soaking the bark in
the
mixture in a twenty gallon container for about twenty minutes. This was to
kill
any snow mold spores that might be on the bark, it was Sequoia bark since
I
could not get any other since Kensington closed. I have been treating the
bark
this way for years without any trouble like this.

Any ideas? Could the bark have been contaminated with an herbicide?