Effect of Papaya Leaf Extracts on the Control of Papaya Anthracnose

Abstract

Objective:The objective of this study was to evaluate whether extracts with different polarities, obtained from papaya (Carica papaya) leaves, have fungicide and/or fungitoxic action in the post-harvest control of anthracnose in papaya fruits. Methods: Hydroethanolic extract was fractionated with organic solvents of different polarities, resulting in hexane, ethyl ether, ethyl acetate, n-butyl alcohol and aqueous fractions. In in vitro tests, concentrations of 0, 500, 1000, 1500 and 2000 mg L -1 , diluted with 10% Tween 20, were used to evaluate fungitoxic and fungicide effects using the Mycelial Growth Inhibition percentage (MGI%) method. Results and Discussion: In in vivo tests, the fraction of leaf extract which had the highest MGI% was used. Severity, expressed by the average diameter of the lesion and calculation of the Area Under the Disease Progress Curve (AUDPC), and incidence of the disease were determined.Analyses of pH, soluble solids, titratable acidity, firmness and mass loss were performed to evaluate the effect of treatments on fruit quality. Aqueous extract, at a concentration of 2000 mg mL -1 , was the most efficient to control the growth of Colletotrichum spp. in vitro. In the in vivo test, an inhibitory effect of the extract was observed at the different concentrations tested, when associated with 10% Tween 20. The use of aqueous extract in fruits did not significantly alter their firmness and soluble solids content. Conclusion: Treatment of papaya fruits with Tween 20, associated or not with aqueous extract, reduced the appearance of anthracnose symptoms.