I have a problem with my Black Mondo Grass which I keep in a pot. I leave it outside much of the time because there's no place within the house with sufficient light, in my estimation. But I do bring it inside occasionally. I water about every three days or so. It has developed some kind of disease which is white, apparently concentrated at the base, and doesn't wipe or wash off as you can see in the photos below. Can anyone help me with this?... identify the disease? ... know the cure? etc.
I live about 30 miles south of San Francisco - Mediterranean Climate
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