There are many different problems people have asked questions about through the course of this thread.
The first one was regarding what appears to be some kind of egg cases on a mango plant. I also noted that in the close-up pictures, it looked like some of the egg cases may have already hatched out. Before applying any kind of spray I think it is important to determine: is it friend or foe? Since no one seemed to recognize what was in the picture, I suggest the following course of action. Get a one quart canning jar (a clean Classico spaghetti sauce jar will do nicely). Pick up some plastic window screen scraps from your local hardware store. Carefully remove some un-hatched egg cases and deposit them in the canning jar. Screw on the canning jar screw cap, minus the lid and some place where you won't forget it or the sun won't cook it. Watch and see what hatches. If they are a friend of the garden, release them. If they are a pest, add a little dish soap, fill with water and dump them down the drain.
As for the fungal diseases, where there is a minor infection use Kop-r spray. For more severe infection, like the nasty looking black one, I suggest cutting the tree back to healthy material and discarding the infected part in the trash or burn it. Make sure the clippers are then disinfected with Clorox so you don't transfer the problem to other plants.
