Occurrence of Phytoplasma Diseases on Coconut (Cocos nucifera) in Bayelsa State, South South Nigeria

Coconut (Cocos nucifera) palms form an integral component of coastal agroforestry systems in Bayelsa State, providing food, oil, and income to rural communities in the Niger Delta. Phytoplasma diseases, including lethal yellowing variants, have been identified as serious threats to coconut palms in West Africa and are associated with progressive decline and palm death. This undergraduate study investigated the occurrence and distribution of phytoplasma-associated diseases in coconut palms across five communities in Bayelsa State during 2023. Symptomatic palms displaying premature nut drop, yellowing of older fronds, rotting of inflorescences, and general decline were recorded and sampled. Polymerase chain reaction amplification using universal phytoplasma 16S rRNA primers confirmed phytoplasma presence in 78 percent of symptomatic samples, with sequencing identifying isolates clustering with the coconut lethal yellowing group (16SrIV). Disease incidence varied between 15 and 42 percent across surveyed communities, with higher prevalence in older palm plantings. Planthopper vectors were observed on symptomatic palms, consistent with the documented transmission biology of coconut lethal yellowing phytoplasmas. Affected palms were not removed in most communities, facilitating continued vector feeding on infected sources. The study recommends urgent community-level awareness campaigns and vector control programmes to slow the spread of phytoplasma among coconut palms in the Niger Delta zone. Keywords: coconut, phytoplasma, lethal yellowing, Bayelsa State, disease occurrence.