Well, it was really only a matter of time before lethal bronzing found its way to Leon County, and that time has arrived. In the last couple weeks, symptomatic palms were sampled in western Leon County and were confirmed to contain the phytoplasma responsible for the disease called lethal bronzing. As many of our fellow Floridians to the west and south have been battling with this disease of palm trees, we now have yet another potential palm disease to be on the lookout for in our area.
Lethal bronzing is a disease capable of infecting several species of palms. It is caused by a phytoplasma, which is a type of bacteria that only occurs in a plant’s phloem cells, the part of a plant’s vascular system that moves the products of photosynthesis. The disease is spread from an infected palm to an uninfected palm with the help of an insect, specifically the American palm cixiid. Unfortunately, once a plant has lethal bronzing there is no treatment and it is recommended to remove the palm as soon as possible after confirmation of the disease. Quick removal of the infected palm or palms reduces the chance that nearby healthy palms will pick up the bacterial disease.
While a lab test is the only way to confirm the presence of lethal bronzing, there are a few tell-tale symptoms that can be indicate disease. The main symptom of lethal bronzing is in the name – browned, or bronzed, leaves. The lower leaves of an infected palm quickly brown out. It is also common to have premature fruit drop or flower clusters that die back before the fruits are able to mature. If you see these symptoms, especially if they develop quickly, then it is recommended that you contact your local UF/IFAS Extension Office to get instructions for a plant disease sample to be assessed at a UF/IFAS plant disease diagnostic lab, located in Quincy, at the North Florida Research and Education Center (NFREC), or at the main campus in Gainesville.
Again, only nearby palms can be proactively treated with an antibiotic, oxytetracycline (OTC), to try and prevent infection. Another option that green-industry professionals can assist with is treatment with insecticides to control the insects that spread the bacteria. It is important to note that the insecticides used to control the palm cixiid will also impact other insects and pollinators, so follow all label precautions.
More detailed information on lethal bronzing is available on the AskIFAS website.
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