Cattleya leaves blackening and pseudobulb drying
 

Hi
I have a problem with my Cattleyas, the leaves of well grown plants are developing black patches and they are not soft and then proceeds to the pseudobulb and then the pseudobulb dries and spreads to the entire plant killing it. I live in Southern India and the weather is ideal for Cattleyas except between Dec-Jan to April when humidity is low. I have used systemic fungicide with little results. Anyone come across this problem with reasons and the control will be of great help.
sastry

That sounds like black rot. This link may be of interest to you. PP260/PP260: Black Rot of Orchids Caused by Phytophthora palmivora and Phytophthora cactorum
Joann

Agreed. aka Pythium.

Thanks for the info, i have a doubt whether the rot will have a soft portion on the leaf as the blackened portion is not soft.
sastry