Baking Soda (sodium bicarbonate) has been found to have fungicidal properties. Researchers at Cornell University discovered that a combination of baking soda and Light Horticultural Oil applied to rose leaves infected with powdery mildew or black spot will significantly reduce the incidence of disease. Timing and rates of baking soda application are important as leaf burning can occur if the level of sodium bicarbonate is too high. No phytotoxicity occurs on roses with rates as low as 1 percent sodium bicarbonate (1 Tbl. baking soda + 2.5 Tbl. Light horticultural oil in 1 gallon of water) but experiments are still being conducted on timing of applications.
Remedy By Bonide
Powder Concentrate – Potassium Bicarbonate 85.0%
This is a reduced risk natural fungicide. This food grade bicarbonate provides outstanding control of many fungal diseases including powdery mildew, leaf spots, anthracnose, phoma, phytopthora, scab, botryrtis and other foliar diseases on woody and herbaceous ornamental plants. It contains a spreader – sticker which helps the material adhere to the plant's leaves. Only 1½ - 2½ Tblsp./gal.
Excellent for roses and vegetable gardens too
For more information go to www.bonideproducts.com