Hello Dave and all, Here in Europe potassium bicarbonate is now used as an organically-approved mildew fungicide. It also appears to have some scab activity. I do not use it as my apples tend towards lower calcium, and I do not want to make that worse by adding Potassium, but I wonder if you use it in the US (and elsewhere in the World).
We also use potassium phosphite against phytophthora diseases, but I am neither sure of its organic status, nor its efficacy. Con Traas
