"P" wrote in a message;
I have brought my Olive tree indoors to avoid frost damage during the
winter. I have noticed on the bark small brown/black mounds, that when
touched crumble to dust. Does anyone know what this could be?
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Possibly Olive Knot (Pseudomonas savastanoi). There's plenty of info.
available on the Internet for this disease. Check out:
http://axp.ipm.ucdavis.edu/PMG/r583100411.htm#SYMPTOMS

MC