Scientist Uncovers Chilling Side of Deadly Avocado Disease

Laurel wilt-damaged avocado tree leaves

Photo courtesy of UF/IFAS

Florida avocado growers have been struggling to put their arms around laurel wilt, a problematic pathogen that’s been decimating their crops. However, new research findings from UF/IFAS might shed some light on when to best scout for the disease.

According to Nemat Keyhani, a UF/IFAS Professor of microbiology and cell science, the disease grows faster in the fall and winter months, so regular scouting should take place from October to March.


To find this out, Keyhani grew laurel wilt at different temperatures in his lab in Gainesville. Though his data are preliminary, Keyhani found the pathogen (Raffaelea lauricola) grows best between 68°F and 79°F, but it barely grows between 86°F and 89°F.

In addition, Keyhani suggests growers might want to change how they eliminate wilted branches so they don’t leave contaminated trees in the area next to healthy trees, as the fungus can spread rapidly as temperatures cool.

“For growers, as a tree presents symptoms, cutting off wilted branches may temporarily result in little to no infection of the rest of the tree during hotter months,” Keyhani stated. “Sometimes that works, and they don’t see the spread of the disease, and they say, ‘OK, things are great.’ But what happens is that, for some reason, the disease will come back after a few months.”