Physan, Phyton or Thiomyl??

[Bayard]

Physan and RD-20 are quaternary ammonium compounds and are commonly used as disinfectants.

Phyton 27 is a copper based fungicide/bactericide.

Thiophanate-methyl and Thiomyl are systemic fungicides used for certain leaf and stem rots (fungi).

I've used all three, but be aware that many fungal and bacterial infections can be prevented by changing cultural conditions. Increasing air circulation, decreasing humidity, decreasing frequency of watering, or using a faster drying medium are all strategies that will reduce or prevent fungal and bacterial infections.

Also, if you have a persistent problem, I would highly recommend sending off a sample to your state agricultural extension for a definitive diagnosis. I'd been having a problem with "stem rot" on my Cattleyas. Turns out it was Pythium, a fungus that commonly causes root rot. The way it manifested itself was the destruction of rhizomes and pseudobulbs. I'd been using the wrong fungicide! I was using thiophanate-methyl (Cleary's) when I should have been using etridiazole (Terrazole) or mefenoxam (Subdue).

I've found ground cinnamon to be an excellent spot treatment for all kinds of "rots".