Garlic can be a fungicide if you know to make it properly, but it really isn’t that difficult. When garlic is mixed with mineral oil it can make for a very effective fungicide. You will want to make sure to use very finely minced garlic with mineral oil and put it in a glass jaw, letting the mixture steep for around 24 hours. Then you will need to strain out the mixture, completely discarding all of the garlic. The next step involves pouring the garlic oil back into the jar.
Make sure that you stir a couple waters of water in with the fish emulsion, adding castile soap. After that you will need to pour the fish emulsion mixture into the garlic oil, but make sure to do it slowly. Add around 2 tablespoons of fungicide with a single pint of water, putting it in a spray bottle so you will be able to use it on your plants.