Ganoderma Butt Rot, an economic disease of the oil palm in south-east Asia and an emerging epidemic in Africa (West, East, and Central Africa), was uncovered in the Eastern Region of Ghana, in 2010. But knowledge gap, coupled with the absence of dedicated-GBR research, allowed the disease to spread steadily, killing infected palms, and endangering the oil palm industry in Ghana. GBR incidence, severity and spread in the Western, Central, and Eastern regions of Ghana, were surveyed quarterly for two consecutive years in selected-commercial oil palm plantations, and small-holder farms belonging to the staff of these commercial plantations. Using the systematic ‘row-by-row walk-through' field survey method, single-point disease assessments were done using Standard Operating Procedure (SOP) with a severity scale of 0 – 4. Results show that the disease incidence for now, is low and endemic in the Eastern Region of Ghana. GBR incidence increased from a low of 6 palms to a high of 29 palms, over the period. Average monthly disease incidence was 1.21 palms and percentage annual disease incidence was 2.90% (or 0.86%/ha/yr). The annual epidemic rate (r) of GBR incidence in Ghana was 0.05 (r=0.05). The putative epidemic threshold was 5.80% (1.72%/ha/yr); epidemic cost was GHC 2 229.86 ($ 202.71) equivalent of fresh fruit bunch loss per hectare per year (FFB/Ha/Yr); and GHC 3 262.73 ($ 296.61) equivalent of crude palm oil loss per hectare per year (CPO/Ha/Yr). Ganoderma butt rot epidemic is predicted in the Western Region, due to the high incidence of coconut-oil palm succession, lack of awareness of the pathogenicity of Ganoderma, and farmer behaviour. This study has arguably provided the first quantitative data (percentage incidence, epidemic rate, economic threshold level, and epidemic cost) on the epidemiology of GBR of oil palm in Ghana, empirical bases for collective advocacy to prevent the disease from assuming epidemic or economic injury proportions in Ghana.

Ganoderma, Coconut-Oil Palm Succession, Knowledge-gap, Economic Cost, Ghana