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The CSPWD is the Ghanaian form of lethal yellowing disease (LYD) of coconut, caused by a phytoplasma and has been active in Ghana since 1932. The paper updates the results of screening trials conducted with 38 pure and hybrid coconut varieties since 1981. Although no variety was found totally resistant, a wide range of susceptibility level was observed: almost all SGD were still unaffected, while the local WAT had almost totally disappeared, additive values were calculated for the parental varieties and it was shown that, in the average, hybrids are slightly more susceptible than predicted by a purely additive model. According to this genetic model, the SGD × VTT hybrid will be appreciably less susceptible than the MYD × VTT currently being used for replanting devastated farms in Ghana. Our results tend to confirm the general trend that cultivars from the Pacific group (especially the Dwarfs) are less susceptible than the Indo-Atlantic cultivars. Proposals are made to adapt planting material to the risk level. Genetic control can only be efficient if it is considered as a link in a chain of control measures involving the choice of a proper planting site, good management and early eradication of diseased trees.

The performance of the coconut hybrid, Malayan Yellow Dwarf x Vanuatu Tall (MYD x VTT) was assessed in Ghana for a period of 6-8 years. The hybrid has previously been identified as being tolerant to the devastating lethal yellowing disease known in Ghana as Cape Saint Paul Wilt Disease (CSPWD). CSPWD is the most important coconut disease in Ghana. It has destroyed approximately 11,000 ha of coconut in Ghana, causing economic hardship to thousands of people. Mortality due to CSPWD during the trial period was only 1.0%. The hybrid showed remarkable tolerance to CSPWD during the 8-year trial period. Mortality, inflorescence emergence and nut load depended largely on the level of farmers’ commitment to basic management practices. In well maintained farms, the hybrid performed two to three times better compared to farms where maintenance was poor.