First report of ‘Candidatus Phytoplasma katsepyensis’, a new species involved in palm lethal yellowing disease in Madagascar
Lethal yellowing disease of coconut (also known as Palm lethal yellowing disease, PLYP, or Palm lethal yellowing type syndromes, EPPO A1 List) has been shown to be associated with different phytoplasma species in different areas where the disease was observed.
In Madagascar, sporadic coconut trees (Cocos nucifera) showing very severe wilt were observed in 2016 in three localities of the western and northern coast of the island: Katsepy, Antsohyhi, and Ambaritsatrana. The causal agent was identified by Pilet et al. as a phytoplasma species closely related to Tanzanian lethal decline phytoplasma (Candidatus Phytoplasma cocostanzaniae’) and later considered as a distinct species, named ‘Candidatus Phytoplasma katsepyensis’.
Surveys were conducted in 2024-2025 to identify the vectors of ‘Ca. Phytoplasma katsepyensis’ in Madagascar. The phytoplasma was detected in asymptomatic Bismarckia nobilis, which are native palms in Madagascar. Three species of Nesomyndus (Hemiptera: Cixiidae) were found associated with palms and tested as potential vectors. The phytoplasma was detected in the salivary glands of N. maculatus and the authors conclude that it is a competent vector of ‘Ca. Phytoplasma katsepyensis’.
Sources
Bahder BW, Ratsimbazafy MR, Randretsiferana SA, Hasinjaka RH, Bloch M, Lane J, Helmick EE, Swale DR, Rakotomalala MR, Pilet F (2026) Detection of Palm Lethal Yellowing Phytoplasma in the salivary glands of Nesomyndus maculatus and asymptomatic Bismarck palms from Madagascar. Phytopathology 116(9), 1414-1423
Pilet F, Rakotoariosa E, Rakotomalala M, Sisterson S, Razakamanana HN, Ravemiafara L (2021) First report of strains related to the phytoplasma associated with Tanzanian lethal decline on Cocos nucifera on the western coast of Madagascar. Plant Disease 105, 4146. https://doi.org/10.1094/PDIS-03-21-0623-PDN