Calcium and silica rev.hodl been a persistently awful summer here so I have been battling it all season. 😠I have been using potsil and water soluble calcium as a foliar (diluted crushed egg shells in cider vinegar as a foliar spray) which works well when used consistently.
However for next years potential grey weather I am starting to gather horsetail (equisetum arvense)for an fpj as looking at it's mineral profile it has boat loads of both which should prevent the mildew from forming.