Alternative postharvest treatment of mango: potential use of essential oil with thymol to control anthracnose development caused by Colletotrichum gloeosporioides

Anthracnose, a fungal disease caused by the Colletotrichum gloeosporioides species is the main postharvest problem of mango (Mangifera indica) production on La Reunion Island. Traditional postharvest treatments involve chemical compounds which do not comply with the expectations of consumers or importing countries. Our goal was to develop alternative postharvest treatments using the fungitoxic properties of two essential oils (EO). Two commercial essential oils X2 (eugenol) and X5 (thymol) were used at various concentrations and compared to an untreated control. A first batch of treatments was tested in vitro for studying mycelial growth and the inhibition of conidial germination. The second experiment measured the effects of the treatments by thymol volatilization on the fruit quality of inoculated mangoes with a suspension of C. gloeosporioides spores. The third experiment measured this fungicide effect with a dipping treatment. In vitro, X5 mainly composed of thymol was very fongitoxic against C. gloeosporioides. Treatment by dipping permitted a control of the disease. Untreated and treated fruits showed a similar quality after sensorial analysis.