Use of antagonistic Yeast in controlling anthracnose caused by colletotrichum gloeosporioides in papaya in Sri Lanka

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.