Chemical fungicides provide primary means for controlling postharvest fungal decay of fruit and vegetables. Continuous use of fungicides faces two major obstacles — increasing public concern regarding contamination of perishables with fungicidal residues, and proliferation of resistance in the pathogen populations. Recently, the exploitation of natural products to control decay and prolong storage life of perishables has received more attention. In this work, hidroethanolic extracts from soapberry (Sapindus saponaria L.) leaves were investigated for their inhibitory activity against Colletotrichum gloeosporioides fungi, the causal agent of papaya fruit anthracnose disease. Fungi inhibitions were tested in different in vitro assays: disc diffusion, spore production inhibition and morphological analysis. The efficacy of extract was seen when 50 ppm and 100 ppm extract were used, resulting in reduction of mycelial growth. The morphological alteration at 50 ppm extract leaded to shorter hyphae that were more branched. At 100 ppm extract the damages in hyphal structure were more severe, causing mycelial disruption. In vivo treatment with 100 ppm extract prevented development of anthracnose symptoms in fresh papaya fruits. Soapberry leaf extract has strong inhibitory activity against C. gloeosporioides, preventing the mycelial growth and reducing the appearance of anthracnose symptoms. Taken together these results demonstrated its potential as a natural fungicide and an alternative control measure for diseases in papaya fruits.

Keywords: anthracnose; postharvest; soapberry; plant extract