Identification of Nedotepa curta Dmitriev as a potential vector of the Côte d'Ivoire lethal yellowing phytoplasma in coconut palms sole or in mixed infection with a 'Candidatus Phytoplasma asteris'-related strain

Over 360 Hemiptera specimens were collected using sweep nets and hand-made aspirators from coconut palm fronds in six villages of Grand-Lahou. Eight families were identified including Aphrophoridae, Achilidae, Derbidae, Flatidae, Membracidae, Pentatomidae, Tropiduchidae, and Cicadellidae, the latter being the most abundant throughout the surveyed villages. PCR assays with primers targeting the 16S rRNA and the secA translocation protein genes yielded PCR amplicons from 216 out of 296 (73%) of the tested specimens of a newly identified cicadellid leafhopper, Nedotepa curta Dmitriev. PCR amplicons were purified, cloned and sequenced. The 16S rDNA and secA sequences from N. curta showed a 99% of sequence identity with those of the Côte d'Ivoire lethal yellowing (CILY) phytoplasma, member of subgroup 16SrXXII-B 'Candidatus Phytoplasma palmicola'-related strain, previously identified in coconut-growing villages of Grand-Lahou. This suggested N. curta as a potential vector for the CILY phytoplasma. Four symptomatic coconut palms (7.4%) were found infected by a phytoplasma of group 16SrI, in mixed infection with the CILY phytoplasma (16SrXXII-B) in two palms, and alone in the other two palms, where the CILY phytoplasma was not detected. The 16SrI phytoplasma was also found in two N. curta specimens, and in the weeds Dalbergia saxatilis and Baphia nitida. Results indicating that mixed infection of both 16SrXXII-B and 16SrI phytoplasmas occurs in coconut palms affected by CILY in Grand-Lahou, and may impact disease management and control.