I live in Puerto Rico and I have a sick old mango tree. It has fungus in the root and some of the leaves are covered in black spots. I don't want it to die . What can I do?

 

Hi Soath,

I'm not familiar with what insect pests and diseases you would have in Puerto Rico, but Florida is close so I searched the Florida Extension Service for info.

You mention a fungus in the root of the tree but there aren't any pics of that. What do you see that makes you think you have a fungal problem in the roots? Is the tree wilting? Do you see mushrooms or conks at the base of the tree?

In your first picture it appears you either have some oozing from inside the tree or sooty mold that has formed on the honeydew from an insect pest. I suspect it's the second one. Look at the info for scale, ambrosia beetles and thrips at the link below. You can google for these pests and get pictures and more info. If you think it's thrips you could search with terms such as:
thrips + mango
redbanded thrips
redbanded thrips + mango

You can also click on 'Images' at google.

The second pic appears to either be a poorly healed pruning cut or the beginning of a burl. If my id is correct, there's not much you can do about either one at this point.

The pattern on the leaf reminds me of Anthracnose. Leaf spot is also a possibility. Read about these problems here to see which better fits the pattern you see. The second site has some pictures.
http://edis.ifas.ufl.edu/PI052
http://edis.ifas.ufl.edu/VH048

Let me know what you think you find or if you need more help.

Newt