black sheaths or leaves on my cattleyas

[james mickelso]

Hi all, I have a question for the knowlegable of you. Some of my catts throw out nice new growths and these come out quite far and then when the second leaf on the growth comes out it is black like it is rotted. I wish I could show a pic but have no digital anything. I would initially suspect it is too much water but that isn't the case. If anything, I underwater my plants. I have always been very careful about watering too much because I live at the beach and cool is the rule. I've never had the problem of black growths before. Anyone else have this problem? Anyone else live down here by Oceanside Ca?

[Ray]

Black growth in cattleyas is often the result of a fungal disease caused by fungi in the phytophthora or pythium genera. It is most common in cool, humid environments, so it sounds like your climate is "perfect".

You are lucky it hasn't progressed down into the rhizomes, or they'd be toast.

Remove all traces of blackened tissue, and treat with a good systemic fungicide (I vote for Cleary's 3336 WP).

Be VERY careful with watering. letting no splashing between plants occur, and water only early in the day so liquid on plant tissues can evaporate quickly.

[Orchonubee]

Great question James. I am glad Ray posted an answer to your question, one that I have had, but not asked. I spray with Consan 20 or Physan 20 and at the same time peal off the black sheath, trimming with sterilized scissors. I have had mixed results. Now to find a reasonably priced source for The Cleary3336 WP.