Most gardener websites from people with limited knowledge about both fungicidal chemistry and biology offer simple solutions that may work with decent results for fungicide prevention and in some rare cases for fungicide disease curing. These remedies also carry some problems of their own, for example, the use of milk containing solutions over plants is proved to encourage the growth of molds and sometimes even stimulate the gathering of ant or similar insect populations. Using alkaline solutions containing bicarbonate or carbonate ions may prove beneficial for prevention but it's effects are readily lost due to rain (which inevitably washes away bicarbonate ions).
In the light of this situation, I have decided to publish the recipe for a fungicide I have been using for sometime, based on US patent No. 6767562 (you can google the patent if you would like to further improve your knowledge on the matter). This mix was designed with both the chemistry and biology of fungus diseases in mind, taking into account that most fungus are sensitive to tannic acid and other chemicals naturally present within certain plant species.
This organic, natural fungicide is quiet simple to make. First, add two thirds of a cup of sage leaves to 1/2 gallon of water and boil it down to 1/3 gallon of water. After this has been done, add 2/3 gallon of red wine (the patent says "fermented grape solution" to make it a little bit harder to guess !") and that's it ! The solution has been proven to prevent and even cure fungus diseases in a variety of crops (as stated in the patent). Now, this information is merely educational and freely available within the patent, if you do not commercialize it you are free from patent infringement. I hope you use and enjoy this excellent organic, natural fungicide that will keep your garden free of those nasty, crop ruining fungus pests !