Observations on Theobroma Cacao in Fernando PO

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Abstract
The geography and climate of Fernando Po Island are considered in relation to cacao cultivation. A text-figure shows the main physical features of the island with isohyets (1500 to 11,000 mm) and cocoa production (units of 50 and 25 metric tons). There are indications that cocoa yields vary inversely with mean annual rainfall. A decline in yields associated with increasing rainfall has been detected in Nigeria, where the epiphytic plants of cacao trees have been used to integrate climatic conditions in the absence of rainfall data. Applications of Bordeaux mixture are generally given to cacao trees on plantations in Fernando Po, for the control of black-pod disease (Phytophthora palmivora). This fungicide suppresses epiphytes, so that a normal population of these plants does not occur on treated trees. However, a limited number of cacao trees in native ownership, had not been treated with Bordeaux mixture, so that epiphytic plants could be observed and collected. Twenty-eight species are listed, as compared with 90 species recorded on cacao in Nigeria. With the exception of one corticolous lichen (Sarcographa thoroldi) all the Fernando Po epiphytic species have been recorded elsewhere in the Continent of Africa, but 12 out of the 28 Fernando Po species have not been recorded as cacao tree epiphytes in Nigeria. It is tentatively suggested that contrasting conditions in the dry season might account for certain dissimilarities between the cacao epiphyte floras of Fernando Po and Nigeria, respectively.