looks like a mold, prune away crap with mold'diseased limbs, open up air, spray a all purpose fruit spray insecticide/fungicide (watered down) or watered down alcohol/water spray. Now your in Texas and maybe you should wait.....but pruning away diseased stuff can't be wrong clean up ground around plant

If you have a county extension agent you might want to check with her.. I don't know

That just looks like sooty mold on the leaf surface, It is a mold that grows on the honey dew from insects (aphids, mealybugs, and whiteflies). The black fungal growth is superficial and can be rub off. You can also first apply a horticultural oil to the leaves then spray it off with a garden hose. The worst thing sooty mold does is block photosynthesis. Insect control is the primary management control.

If you are referring to the black stuff, it's sooty mold. I have it too. I need to spray my trees with neem oil.

This is great news thank you. I have neem oil so I'll spray the trees tomorrow.

What does you area have for your problem? Can you bring a few leaves to your extension office or local nursery and ask what products they have that would fix the issues you are dealing with. I would for sure since your trees are defintley salvagable!

Mike