I joined for the same question. I have tons of comfrey with powder mildew on it, with the past advice that comfrey helps "burn out" or use up the mildew. But a year or two later, there is still a lot of mildew, and I begin to worry about chop and dropping the mildewy leaves. Some sources say it's no problem for the fruit being mulched by the comfrey, but I have it below a young peach that had leaf curl. Wondering if it's bringing the mildew back into the soil and should be removed instead.