Mites

Without a picture I suspect Diaprepes root weevil or little leaf notcher. Fortunately the weevils are said to prefer to feed on weed (grass) roots, so they don’t damage the tree roots. The best solution (if you can do it) is to get rid of any grass, which not only takes away the food source of the grubs but also frees up nutrient resources that would have been consumed by the grass. You can lay down heavy layers of (free) mulch which then attracts beneficial creatures (worms, millipedes, etc) and adds to the quality of the soil. I wouldn’t worry too much though, damage is mostly cosmetic. On the other hand, however, you also have a serious spider mite infestation. Spider mites commonly infest mangoes in Florida. Feeding and is first confined to the upper leaf surface, along the midrib, and then along secondary veins. The areas along the veins become reddish-brown. Infested leaves often abscise prematurely. Horticultural oils and neem oil work by smothering immobile insects such as scales, aphids, and mites and are applied fall, winter and spring. Do not apply when daytime temperatures reach 85 degrees.