In October 2008, coconut plantations in the villages of Tobenam, Pupun and Dugumor, located in the Bogia district of the Madang Province in Papua New Guinea (PNG), exhibited lethal yellowing-like symptoms in both newly planted and old palms. Symptoms started with premature nut fall, followed by leaf yellowing and collapse of the crown leading to the death of the plant. Inflorescence necrosis, a symptom frequently linked with lethal yellowing (LY), was absent. The disease spread rapidly from neighbouring affected palms, and farmers have reported losses totalling over 5000 trees in the Bogia district. BLAST comparisons showed that the partial 16S rDNA sequence of the LY-PNG phytoplasma matched most closely (96%) with members of group 16SrIV, coconut lethal yellowing (CLY). Phylogenetic analysis supported BLAST comparisons since the LY-PNG phytoplasma clustered as a single distinct branch related to group 16SrIV. CLY has previously been reported from the Americas and Caribbean. Other closely related lethal yellowing-like diseases have also been recorded from West Africa (Nigeria, Ghana, Togo, Cameroon), East Africa (Tanzania, Kenya, Mozambique) and the Far East (Kalimantan, India, Sri Lanka, Indonesia and Malaysia). This is thought to be the first report of the presence of a lethal yellowing-like disease of coconut in Oceania.
Kelly, P.L.; Reeder, R.; Kokoa, P.; Arocha, Y.; Nixon, T.; Fox, A. First report of a phytoplasma identified in coconut palms (Cocos nucifera) with lethal yellowing-like symptoms in Papua New Guinea. New Disease Reports (2011) 23: 9. [DOI: 10.5197/j.2044-0588.2011.023.009]