I have been noticing my Rhyncholaelia digbyana has not been looking quite right so I inspected it today. It has the dreaded black rot but only on one side of the plant. So, I pulled it out of the pot, sliced off everything that looked infected and washed away all of the potting medium. I filled a bucket with rain water and added a heaping tablespoon of Dithane-M45. I soaked the root ball in this solution for more than an hour. I then sprinkled cinnamin all over the roots and repotted it in fresh bark. If that wasn't enough, I poured the remaining fungicide solution over the plant. I hope this works as I love that orchid.
Jim
