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Lethal Yellowing was detected in Florida in thr 1950s when it killed coconut palms that had dominated the South Florida landscape. A decline of sabal (cabbage) palm with symptoms similar to those of Lethal Yellowing was first observed in west central Florida in 2006. This disease was named Texas Phoenix Palm Decline, due to its initial discovery in Phoenix spp. palms in Texas in the 1970s but is also referred to as Lethal Bronzing. Lethal Bronzing affects some of the most commonly planted palm species in Florida, thus posing a threat to the Florida landscaping and nursery industry. Sabal palm is a native and iconic ornamental palm, and an important symbol in the identity of Florida as the official state tree.

CAUSAL AGENT

Uncultured bacteria called phytoplasmas. They are transmitted primarily by phloem-feeding hemipteran insects, including leafhoppers, plant hoppers and psyllids. There are at least 42 phytoplasma species within the genus Candidatus. Phytoplasma impact a wide variety of agricultural and ornamental crops.

DISEASE SYMPTOMS

  • Premature dropping of coconuts
  • Darkening of flowers
  • Fronds turn yellow
  • Death of the bud

HOST RANGE

  • 34 palm species

SPREAD of the PATHOGEN and CONTROL OPTIONS

Individual palms may be treated preventively or at the onset of symptoms with oxytetracycline HCl, which suppresses the pathogen. The vector of Lethal Yellowing is believed to be Haplaxius crudus, but the vector(s) of Lethal Bronzing is currently unknown. Phytoplasmas typically use herbaceous grasses as alternative hosts. Identification of alternative hosts is needed to reduce disease spread.

MORE RESOURCES

UF/IFAS Extension – Lethal Yellowing

UF/IFAS Extension - Texas Phoenix Palm Decline

 


Prepared by Marina Ascunce and Erica Goss, EPI and UF/IFAS Department of Plant Pathology Department of Plant Pathology.