Yeast potential in controlling Aspergillus sp. causing fruit rot disease in dekopon oranges (Citrus reticulata ‘shiranui’)

Fruit rot disease caused by Aspergillus sp. is a post-harvest disease in citrus. Yeast has the potential as a biocontrol agent against airborne pathogens. This study aimed at testing the potential of yeast Aureobasidium pullulans Dmg 11 DEP, Rhodoturula minuta Dmg 16 BEP, and Candida tropicalis Lm 13 BE in controlling fruit rot disease caused by Aspergillus sp. on dekopon orange. The experimental stages consisted of testing the potential of yeast in suppressing Aspergillus sp. with five treatments and four replications and in vivo six treatments and four replications on dekopon oranges using a completely randomized design (CRD). The study was conducted at the Plant Protection Biotechnology Laboratory, Universitas Padjadjaran, Indonesia, from January to July 2022. Antagonism and interaction tests were conducted in vitro by dual culture method by placing the Aspergillus sp. alongside the yeast (A. pullulans Dmg 11 DEP, R. minuta Dmg 16 BEP and C. tropicalis Lm 13 BE). Observations were made on the yeast effect on the growth of Aspergillus sp. and suppression of Aspergillus sp. rot disease in dekopon orange fruit. The test results showed that the yeast isolate could inhibit the growth of Aspergillus sp. in vitro with a 22.5–42.2% inhibition percentage in the dual culture test and 30.89–46.89% in the volatile compound production test. The yeast also suppressed the incidence of Aspergillus rot disease with an inhibition percentage of 21.06–51.98%. Aureobasidium pullulans Dmg 11 DEP recorded the highest percentage inhibition (51.98%) of Aspergillus sp.