Abstract:
Anthracnose, which is caused by Colletotrichum gloeosporioides, is one of the most prevalent
papaya diseases in Sri Lanka. Although it is controlled by a variety of chemical fungicides, the
possibility of the pathogen developing a chemical resistance and consumer demands made the
need for a biocontrol technique to manage this disease. Additionally, using biocontrol
techniques that have been developed in other countries may have negative effects on
nontargeted organisms. Therefore, this study intended to assess the antagonistic yeasts' potential
to inhibit the growth of C. gloeosporioides in papaya in Sir Lankan context. Four types of yeasts
were isolated from Carica papaya L. (Papaya) leaf surfaces, Psidium guajava L. (Guava) leaf
surfaces, Cocos nucifera (Coconut) water and Baker’s Yeast solution (Sacchsromyces
cerevisiae)(Y162, Y234, Y342, and Y467 respectively) were isolated. C. gloeosporioides was
isolated from diseased papaya fruits and morphologically identified based on their colony
characteristics and spore characteristics. The dual culture assay was used to examine the
antagonistic activity. Commercial antibiotic, Fluconazole was used as the positive control. All
four yeast isolates had shown significant antagonistic activity against C. gloeosporioides (One
way ANOVA, P <0.05), which was even higher than the positive control. The highest The
Percent Inhibition of Radial Growth (PIRG %) was observed with Y162 yeast variety
(59.3±2.0). In Vivo, the variety Y162 caused 66.2% reductions in disease incidence. According
to these findings antagonistic yeast Y162 could be utilized as a possible biological control agent
against the anthracnose disease caused by C. gloeosporioides in papaya in Sri Lanka.
