In this study, the effect of crude extract of cocoa infected with Phytophthora palmivora were tested for and their ability to confer protection on cocoa pods in the field against black pod disease/pod rot. Dichloromethane was used to extract the phytochemicals from infected cocoa pods. The extract was concentrated using rotatory evaporator at 40°C. Three categories of matured unriped and uninfected cocoa pods were used in the field trial in a cocoa farm in Iworoko – Ekiti, near the University of Ado – Ekiti campus. The first category were made up of 3 sets of cocoa pods sprayed with 100 mg/ml, 200mg/ml and 300 mg/ml of the crude extract respectively. The second category were also made up of 3 sets sprayed with 3 different conventional fungicides (Ridomil, Funguran and Copper Sulphate) used for the control of black pod disease. The third category of cocoa pods were not sprayed with either the induced crude extract or conventional fungicides. These served as the control. The categories were later sprayed with a 10 day old standardized mycelial suspension of P. palmivora (0.600 absorbance at 450 nm). Daily observations of the three categories of cocoa pods were made for 14 days. It was observed that the first and second categories of cocoa pods showed no symptoms of black pod disease while the third category (control) showed symptoms of black pod disease after the fifth day of the experiment. From this field trial, it could be concluded that the induced crude extract from infected cocoa pods compare favourably with conventional fungicides in prevention of black pod disease of cocoa in the field.
Key words: Cocoa induced crude extract, black pod, field trial, Phytophthora palmivora.
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