We in the Pacific Northwest USA use potassium bicarbonate extensively for powdery mildew control in both organic and conventional sweet cherries.
Timothy J. Smith WSU Extension From: [email protected] [mailto:[email protected]] On Behalf Of Con.Traas Sent: Monday, February 15, 2010 1:18 AM To: [email protected] Subject: Apple-Crop: Other organic-approved chemicals 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
