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Several palm plants have social and economic roles worldwide by providing drinks from their sap. In Côte d'Ivoire, management of the coconut sap is not yet practiced. In this study, parameters related to production of sap have been assessed from four coconut cultivars namely PB 113 + and PB 121 + hybrids and WAT and MYD varieties. From all the unopened inflorescences (spathes) studied into the coconut crown, whose ranks varied from 7 to 9, that of rank 8 yielded the highest volume of sap. From this spathe, the PB113 + hybrid provided the best yield of sap (61.81 ± 20.41 l). Most important proportion of that sap volume was recorded at the morning harvesting. The sap production duration of a spathe varied from 24 ± 1.87 days (MYD) to 46.78 ± 1.86 days (PB 113 + ). That duration depended on the length of spathes and regular sap flow allowed by them. Furthermore, the PB 113 + had the highest number of fruits (NBF = 174.33 ± 78.45 fruits). The results showed that volume of sap available is closely related to the length of production (r = 0.78) and the cultivar's nut yield (r = 0.82). The use of PB 113 + hybrid which provided highest quantity of sap is recommended for promoting the production of coconut sap in Côte d'Ivoire in order to improve the benefits derived from this plant.

Surveys for the Côte d'Ivoire lethal yellowing (CILY) phytoplasma were conducted in eight severely CILY-affected villages of Grand-Lahou in 2015. Leaves, inflorescences and trunk borings were collected from coconut palms showing CILY symptoms and from symptomless trees. Total DNA was extracted from these samples and tested by nested polymerase chain reaction/RFLP and sequence analysis of the 16S rRNA, ribosomal protein (rp) and the translocation protein (secA) genes. The CILY phytoplasma was detected in 82.9% of the symptom-bearing palms collected from all the surveyed villages and from all the plant parts. Trunk borings were recommended as the most suitable plant tissue type for sampling. Results indicate that the CILY phytoplasma may have a westward spread to other coconut-growing areas of Grand-Lahou. CILY phytoplasma strains infecting coconut palms in the western region of Grand-Lahou exhibited unique single nucleotide polymorphisms on the rp sequence compared to the strains from the eastern region. Moreover, single nucleotide polymorphisms on the SecA sequence distinguished the CILY phytoplasma from the Cape St. Paul Wilt Disease phytoplasma in Ghana, and the Lethal Yellowing phytoplasma in Mozambique. (Résumé d'auteur

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The diversity of culturable bacterial and fungal communities was assessed from leaves, trunk and rhizosphere of coconut palms infected and non-infected by the Côte d'Ivoire lethal yellowing (CILY) phytoplasma. Bacterial and fungal microbes were isolated from leaves, trunk and rhizosphere samples collected from two villages of Grand-Lahou, Braffedon and Yaokro, by using a high-throughput 'dilution-to-extinction' cultivation method coupled with PCR and sequencing with primers that amplified both the 16S ribosomal RNA and intergenic transcribed spacer (ITS) genes. The relative abundance was higher for Bacillus and Candida in Braffedon, and Burkholderia and Neodeightonia in Yaokro. Commonly genera identified from rhizosphere included Bacillus, Burkholderia, Pseudomonas, Streptomyces, Cryptococcus, Penicillium, Purpureocillium and Trichoderma. The most abundant endophytes identified were Pantoea, Candida, Cryptococcus, Bacillus, Pseudomonas, Penicillium, Aspergillus and Rhodotorula. Genera limited to symptomless palms included Arthrininum, Chaetomium, Phialemonium, Fusarium, Klebsiella and Candida. Results indicate that the CILY phytoplasma may be a factor determining the level of diversity of a microbial community in a given location. Our research provides the basis to investigate the possible effect of endophytic and rhizosphere microbes against the CILY phytoplasma to further effectively improve the management of CILY in Grand-Lahou.

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.

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