About lethal bronzing
Lethal bronzing, a fatal disease of palms, occurs throughout central and south Florida. Found in popular palms like the Canary Island date, queen, and pindo, the disease infects twenty-one known palm species. A bacterium without a cell wall, known as a phytoplasma, causes the disease. This phytoplasma resides in the sap of infected palms. The leafhopper insect, Haplaxius crudus, which carries the disease in its mouthparts, transmits the disease by feeding on palm sap and infecting the vascular system.
Previously known as Texas Phoenix Palm Decline (TPPD), the disease now goes by lethal bronzing, reflecting its occurrence outside of Texas and its impact on more than just Phoenix palms. It shares a close relation with Lethal Yellowing, a disease that devastated coconut palms in South Florida in the 1970s.
Lethal bronzing symptoms
Symptoms first manifest on the fruit and flower stalks, leading to fruit drop and the blackening or distortion of flower stalks. A bronze discoloration occurs on the lower leaves. Ultimately, the disease kills the spear leaf and the main bud, resulting in the palm’s death. The progression from infection to death is relatively quick, typically around four to five months, although the timeline can vary by species. Many times, symptoms may not appear until weeks to months after the initial infection.
Submitting samples
If one suspects lethal bronzing on a palm, they should submit a sample to a UF/IFAS lab specializing in diagnosing this disease. To avoid contamination, it’s crucial to follow the sampling instructions precisely. Sample collection requires special tools, such as a 5/16 six- to eight-inch-long drill bit and a propane torch. Complete step-by-step instructions and a list of tools are available at https://edis.ifas.ufl.edu/in1197.
Management and Treatment
Following UF/IFAS research-based recommendations, if testing confirms a positive sample, the best course of action involves removing the affected palm as soon as possible. Testing asymptomatic palms close to the infected one is also advisable; any that test positive should also undergo removal. Once a palm contracts the disease, it is fatal with no cure available. Despite this, there is some hope for palms through the administration of an antibacterial treatment called oxytetracycline HTC. This treatment requires administering injections three to four times per year for throughout the palm’s lifetime. It’s critical for central and south Florida municipalities, arborists, and other landscape industry professionals to understand how to effectively treat palms for lethal bronzing disease. UF/IFAS provides a comprehensive guide outlining the treatment process.
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Grammarly assisted with grammar and spelling corrections, which improved this blog post.
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