Biological Control of Fruit Rot and Anthracnose of Postharvest Mango by Antagonistic Yeasts from Economic Crops Leaves

To select antagonistic yeasts for the control of fruit rot caused by Lasiodiplodia theobromae and anthracnose caused by Colletotrichum gloeosporioides in postharvest mango fruit, 307 yeast strains isolated from plant leaves were evaluated for their antagonistic activities against these two fungal pathogens in vitro. Torulaspora indica DMKU-RP31, T. indica DMKU-RP35 and Pseudozyma hubeiensis YE-21 were found to inhibit the growth of L. theobromae whereas only Papiliotrema aspenensis DMKU-SP67 inhibited the growth of C. gloeosporioides. Antagonistic mechanisms of these four antagonistic yeasts in vitro consisted of the production of antifungal volatile organic compounds (VOCs), biofilm formation and siderophore production. T. indica DMKU-RP35 was the most effective strain in controlling fruit rot on postharvest mango fruits. Its action was comparable to that of the fungicide, benomyl, reducing the disease severity by 82.4%, whereas benomyl revealed 87.5% reduction. P. aspenensis DMKU-SP67 reduced anthracnose severity by 94.1%, which was comparable to that of using benomyl (93.9%). The antifungal VOCs produced by these yeast strains also reduced the severity of these diseases on postharvest mango fruits but at lower rates than using yeast cells. Therefore, these antagonistic yeasts have the potential for use as biological control agents for the control of fruit rot and anthracnose diseases.