Overview of the Epidemiology of Coconut Lethal Yellowing Disease (LYD) in Malayan Yellow Dwarf x Vanuatu Tall (MYD x VTT) Hybrids in the Western and Central Regions of Ghana

Abstract

The Ghanaian form of lethal yellowing disease (LYD) of coconut is known as the Cape Saint Paul Wilt Disease (CSPWD). The disease is caused by phytoplasmas, and has been active in the country since 1932. The study was conducted to update the disease situation among Malayan Yellow Dwarf x Vanuatu Tall (MYD x VTT) hybrids in the Western and Central Regions of Ghana. It was also to compare the level of LYD susceptibility in the local West African Tall (WAT) variety and the MYD x VTT hybrid, recommended for replanting under the Coconut Sec-tor Development Project (CSDP). Structured survey questionnaires were administered for 15 months to obtain information on every CSPD coconut farm. Categories of data included: farm identity, hydrography, topography, soil properties, agronomic and ecological condition, and dis-ease situation around each coconut farm. Losses to LYD were higher in the Central Region than in the Western Region. Overall, only 4.8 % of total hectarage of MYD x VTT coconut plantings have been affected by the disease as at December, 2009. LYD incidence was significantly higher in the WAT variety than the MYD x VTT hybrids. Mathematical calculations also showed that, the epidemic rate (r) of LYD was higher in the WAT variety than the MYD x VTT hybrids. There was variation in disease incidence and severity in MYD x VTT hybrids between the different co-conut growing areas. The susceptibility of the MYD x VTT hybrids under intense disease pres-sure calls for the screening of more coconut varieties, to identify truly resistant types to the lethal yellowing disease.