Question
Hi Ms Kathy,

 I found some black patches on my orchid leaves. At times,
I would mist the crown of the plant. Is this fungal/viral
infection? Would it go away with the application of
liquid fungicide?

Rgds

Answer
HI Alfredo, Hope this helps I found on a website for you....kathy
What should I do about the blacked area on the leaves of the plant?
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.

What causes the tip or ends of the leaves to become blackened?
Blackened leaf tips may be caused by hard water, overfeeding with orchid nutrients or fungal disease. Remember that the potting mix needs to be flushed out thoroughly with plain water in between feeding. Cut off any black tips on leaves to prevent the die -back from continuing to run back down the leaf. Use a sterilized pair of scissors.