Pseudobulb rot

[coli0157]

Hello,
I have a large oncidium sharry baby that has one pseudobulb that is rotting. There are two new growths on the plant as well. My initial thought was to remove the entire rotting bulb and treat the remaining plant with phyton 27 and hope for the best. Its odd, the plant looks healthy everywhere but the one bulb. What do you think I should do? Thanks for your help.
Jeremy

[canadacarol]

That sounds like a good idea.
What I use is Original Listerine full strength, but the phyton (or is it Physan) might work even better.

[Ross]

Treat the good part of the orchid after you cut off the rotting pseudobulb. Also soak the potting medium in Physan 20 as well. The bottle should have the 5 to use to soak the medium. Rinse the medium off with plain water then repot the orchid. I would leave the orchid out of pot for a few days to let the cut area heal or treat with cinnamon (see article on main part of the board.) Good luck.

[coli0157]

Thanks for the suggestions...everyone seems to use Physan 20 for their orchids but I got Phyton 27. I heard from the locals here that it is much better. I assume that its basically the same thing but the Phyton says its systemic and stays in the plant. I havent used it yet but I will let everyone know what happens. Thanks again.

[Ironwood]

Older pseudobulbs do die off, it may be just natural aging occurring.

[Ray]

Assuming things can get you in trouble:

Physan is a solution of quaternary ammonium salts - basically a hospital disinfectant that is an effective topical bactericide, fungicide, algaecide and virucide. It's a good wetting agent and is biodegradable. No gloves are needed when handling the diluted solution, and there is no restricted entry interval (waiting period) before going back to where it was sprayed.

Phyton 27 is a copper sulfate pentahydrate solution, and as such can be absorbed by the plant to provide bactericidal and fungicidal protection. However, copper sulfate is also a very effective herbicide and has been show to be damaging to thin-leaved plants. It is a corrosive and can cause irreversable eye damage and skin burns, according to the MSDS, and requires protective eyewear, gloves, long sleave shirts, etc., as PPE, but I suspect that all applies far more to the concentrate than to the dilute solution.

[Ross]

Thanks Ray. You are absolutely right about assuming.

[justatypn]

Originally Posted by canadacarol

That sounds like a good idea.
What I use is Original Listerine full strength, but the phyton (or is it Physan) might work even better.

Never heard of listerine being used...do they gargle it or what ... Share in this use, sounds interesting..what a great

[ScottMcC]

for this problem, I have a few quick questions. is this one of the oldest bulbs, and what exactly does it look like? black, soggy, smelly? rapid onset? or has this been a more gradual progression of an old bulb getting the dwindles, and eventually getting yellow and shrivelled?

if it's the first, especially if it's a newer bulb, take off all affected tissue immediately, followed by a margin of healthy tissue. then treat the plant with something big and bad, like phyton (just be sure to use precautions like Ray suggested).

otherwise, you may be ok leaving the old bulb, or just pulling it off and giving it a little hit of physan.

I had a similar problem with fungal rot on one of my favorite cattleyas, that I first tried to treat conservatively, but it ended up failing miserably, and that plant has now died, after repeated attempts to whittle away at the damage. so be warned!

[ScottMcC]

oh and by the way...to the original poster, nice user name. E coli O157:H7 is one of my favorite strains of nasty bugs, and luckily one that we don't see too much.