|I have a very larage orchid that has done very well for years. It was professionally repotted a few months ago and has been doing well. This past weekend I noticed the new growth is turning black. some of it has yellow areas with black areas. Help. Please help.|
|Blackened area on leaves may be caused by either sunburn or bacterial or fungal disease.|
The appearance of black areas on the surface of the leaves, following a hot sunny day may be the result of sunburn. Exposure to direct mid-afternoon sunlight during the late spring through early fall will scorch the leaves of some orchids. Increase the shading or move the plant to a less sunny location.
If the blackened area increases in size, this is an indication of bacterial or fungal disease. Cut off the diseased area with a sharp, sterile tool(i.e., razor blade or knife). Then treat the plant with a fungicide like Physan 20.
Good luck with your orchid.