Thanks for the replies. I'm in Venice, south of Sarasota. The Beaumont suddenly started showing brown leaves, and every day there were more of them. In a week the entire tree was covered with them, not a green leaf to be found! I read somewhere it was a fungus infection and highly contagious to the other trees, so I pulled it out and burned it. The shame of it is that it was a very productive, fast-growing tree. Broke my heart!