Photo: http://www.growingproduce.com/fruits/avocado-tree-killer-on-the-move-in-florida/
Avocado Tree Killer On The Move In Florida
This appears to be the equivalent of citrus greening only in avocados. The vector (insect that transfers the disease) is the Redbay Ambrosia Beetle.
Great video here of symptoms to look out for:
https://youtu.be/2x7vgFWLHkY
Pictures and more information here:
http://www.freshfromflorida.com/Divisions-Offices/Plant-Industry/Agriculture-Industry/Pests-Diseases/Laurel-Wilt-Disease
https://edis.ifas.ufl.edu/hs379
