Here are my avocado leaves from both sides. Can anyone please tell what kind of fungus or thing this is? It's causing all the leaves with those dark spots.
This is a 30 feet tall "don't know how many years old" avocado tree in a small town in the Gulf of Mexico. It's shaded by bigger mango trees in the back of my yard.
There looks to be a scale insect on the right hand leaf, and the top surface of the leaf looks infected with sooty mold. Treatment can be with a horticultural oil to smother the insects which secrete the sweet honeydew that gets infected with molds. Such insects include scale, aphids and mealy bugs. Look for ants in the latter case as ants farm these bugs for the honeydew and if you treat the ants nature might take care of the bugs.