I have a fungus (black spot) on my ficus tree. It is potted in a well draining bonsai soil and I water it from the top with a fine mist only when the soil begins to dry out. I have purchased and applied an organic fungicide (EcoSmart garden fungicide). The tree is losing some leaves and it seems to be getting worse instead of better. My other trees (another ficus, 2 Chinese Elms and a Trident Maple) seem unaffected. Does this tend to spread to other trees? Can this eventually kill the tree? Anyone have any other methods for curing this? Any thoughts or advice would be greatly appreciated. Not sure how I got into this mess, but I'd love to be rid of it.