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*Corresponding Author: Falade MJ Received: 5/11//2022| Accepted: 11/11/2022| |
Published: x/x/2022 |
Abstract Cercospora black spot of pawpaw caused by Cercospora papayae is responsible for 50-70% yield loss of pawpaw when not controlled. Based on the above, laboratory studies were conducted to evaluate the effect of hot water leaf extracts of four plants: Castor oil leaf (Ricinus communis), African eggplant (Solanum macrocarpon), scent leaf (Ocimum gratissium) and Tobacco leaf (Nicotiana tabacum) in the management of the disease. Three concentrations of the extracts (15, 30 and 45) were prepared and applied in-situ to determine their efficacy of control on cercospora black spot disease of pawpaw. The result of the studies shows statistically significant (P ≤ 0.05) variation in C. papayae growth depending on the extracts and concentration. N. tabacum at 45% concentration was the most effective in reducing the growth of the fungus and this was closely followed by S. macocarpon and R. communis while that of O. gratissimum was the least. Growth rate induced by N. tabacum at 45% concentration was 2.38 mmday-1 while that of S. macrocarpon and R. comumis were 2.92 and 3.15 mmday-1 respectively. There was 60-84% inhibition of conidia germination irrespective of plants extracts and concentration but the extracts do not have effects on sporulation. The study concluded that the active compounds in the leaf extracts can be developed into synthetic fungicide for the management of cercospora black spot disease of pawpaw.
Keywords: Pawpaw, Cercospora papayae, Plant extract, Inhibition