Do I need to take this huge tree down? And, what probably caused this? So sad as this tree has produced so many fruit for 10 years I've lived here.
Avocado Tree Has All Brown Drooping Leaves After Years of Great Production
Certified GKH Gardening Expert
Contacting your local university extension service is the best option, since they have information on the pests and diseases present in your area.
One possibility is buildup of salt, fertilizer, or other toxins in the soil. In this case, the leaves would turn brown starting at the tips and edges, moving in toward the center. Harsh weather, especially high heat and drought can cause these problems as well.
Another possibility is laurel wilt disease or another wilt disease. Unfortunately, these diseases are not curable and will kill the tree. Laurel wilt can infect avocados and is present in Florida. Please see the below articles for more information: