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The only fungicides currently acceptable for use within most organic programs are elemental sulfur, lime sulfur, Bordeaux mixtures (copper plus lime), and basic copper sulfate.Sulfur is highly effective for control of powdery mildew. It is "at best" only fair for control of apple scab and summer diseases and provides minimal or no control of rusts. A major problem with the use of sulfur as a fungicide is the lack of residual protectant activity. Sulfur only provides about 3-5 days of protection without any rain washoff. When sulfurs were the only fungicides being used in the past, up to 25 applications per season were necessary to obtain satisfactory control. It should be noted that sulfur is toxic to many beneficial insects, spiders and mites. These beneficial insects are natural predators of harmful insects and mites that affect fruit crops. Killing these beneficial insects may increase certain insect problems, especially with mites. Hope this helps. Dennis Norton
Royal Oak Farm Orchard, Zone 5 http://www.royaloakfarmorchard.com http://www.theorchardkeeper.blogspot.com http://www.revivalhymn.com
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