The use of antagonistic yeast for anthracnose disease control in avocado fruit during storage

Abstract

Anthracnose caused by Colletotrichum gloeosporioides is an important disease in avocado fruit during storage. An effective, cheap, and safe control method is necessary as an alternative to subtitute the use of fungicides in postharvest disease control. This research aims 1) to get a yeast antagonist from avocados that are effective in controlling anthracnose disease on avocado fruit, 2) to identify effective yeast antagonists to control anthracnose disease on avocado fruit, and 3) to examine mechanism of action of yeast antagonists in controlling anthracnose disease on avocado fruit. Research started with isolation of C. gloeosporioides and yeast from avocado fruit, followed by bioassay in vivo, antibiosis test, and chitinolitic activity test. In vivo testing was done by dipping avocado fruit on yeast cell suspension to suppress the anthracnose disease in avocado fruits. The isolation of yeasts from avocado obtained 23 yeasts isolates. Based on bioassay in vivo, there were eight yeast isolates (A28, A32, A33, A34, A35, A36, A37, A38) that effectively inhibited anthracnose disease in avocado fruit at a concentration of 106 cells/ml and 107 cells/ml. However, only four isolates were chosen for further characterization based on morphological and molecular identification. Two species of yeast was identified, i.e Pichia anomala (isolates A33 and A37) and Candida intermedia (isolates A35 and A36).