My mango and orange trees have lot of black fungus on the leaves. I tried to spray Neem fungus treatment and clean the leaves individually also as much I could but seems like it's an unending job. Also, I can't succeed at growing the Loquat tree. It just dries and dies. PLEASE help. I love my little fruit garden. I don't have the images available at this moment.
Here are some articles to help you.