Antagonistic yeasts isolated from bioferments of mountain microorganisms (MM): an alternative for the control of fruit anthracnose caused by Colletotrichum tamarillo

Antagonistic yeasts emerge as a friendly option for the control of anthracnose, a postharvest disease caused by phytopathogenic fungi of the genus Colletotrichum. This study evaluated, under laboratory conditions, the antagonistic activity of 24 native yeasts isolated from fermentations of mountain microorganisms (MM) against Colletotrichum tamarillo through dual confrontation tests, production of volatile organic compounds (VOCs) in mouth-to-mouth tests and the evaluation of the ability to control the development of rotting wounds infected with Colletotrichum tamarillo in tree tomato fruits (Solanum betaceum) in preventive and curative treatments. In this study, 5 of the 24 isolated yeasts showed antagonistic potential, Pichia kudriavzevii GRB-LB11 presented the highest antagonistic potential in dual culture (PICR of 41.3 ± 2.1%), and Pichia kudriavzevii GRB-LB02 presented the highest production of VOCs in mouth-to-mouth tests (67.3 ± 2.6%). For the tests on tree tomato fruits, Pichia kudriavzevii GRB-LB11 and Candida haemulonis GRB-LB06 controlled 100% of the incidence of the disease in the preventive treatments, reducing the diameters of the wounds caused by Colletotrichum tamarillo to 0 ± 0 cm. In the curative tests, Candida haemulonis GRB-LB06 managed to reduce the incidence of the disease by 96.8 ± 5.2, reducing the diameters of the wounds caused by Colletotrichum tamarillo to 0.1 ± 0.16. The results support the agroecological benefits of MM ferments and the biotechnological potential of isolated yeasts for anthracnose control