ETAPOD: A forecast model for prediction of black pod disease Outbreak in Nigeria

The misuse of toxic fungicides by indigenous cocoa farmers in Nigeria stem from their inability to predict the time for black pod disease (BPD) outbreak. Prediction of possible time for BPD outbreak will provide spotlight on areas under massive BPD invasion, minimise fungicide misuse and increase control accuracy. The Multiple Regression Model (MRM): Y=+{beta}1X1+{beta}2X2+...+{beta}nXn where Y is Nx1 matrix of response variable, X1,X2,...Xn are NxK matrices of regressors, and {beta}1,{beta}2,...{beta}n regression coefficients was used in model development. Eight models (MRM1-MRM8) were fitted from real life BPD data. The performances of the models were ascertained using SER, RMSEpred and R-SqAdj. Prediction(s) made by the best fitted model was compared to real life observations (Monthly BPD Occurrence (MBO), Total Annual Occurrence (TAO), and Average Annual Occurrence (AAO), respectively). The preferred model was MRM5 (ETAPOD) followed by MRM4, MRM1, MRM2, and MRM3 in terms of SER (0.22, 0.39, 0.45, 0.45 and 0.45), RMSEpred.(0.30, 039, 0.46, 0.46 and 0.46) and R-SqAdj.(0.67, 0.49, 0.32, 0.32, and 0.31), respectively. Predictions on BPD outbreak made by ETAPOD showed that MBO, TAO and AAO for some selected stations i.e. Owena and Waasimi were 9.05, 72.3 and 6.0% compared with observed BPD values of 9.5, 70.0, and 5.8%, respectively. Adaagba, Iyanfoworogi, and Owode-Igangan had 9.43, 77.8, and 6.5% as their predicted BPD values compared with the observed values of 9.0, 53.5, and 4.46%, respectively. ETAPOD performed better than other models and its predicted values were within the range of real life occurrence.