GROWING RESOURCE MODIFICATION EASES THE COMPLICATIONS IN ISOLATING Mycosphaerella ORIGINATING FROM BANANA

Abstract

Experimental study on the Mycosphaerella species complex was often limited by the availability of the isolates due to problems in the isolation process. Two symptomatic leaves from initial and later infections were used as the source of isolates. As critical environmental factors for fungal development, we observe different pH (5.5, 6.0 6.5, and 7.0) and antibiotics (chloramphenicol and amoxicillin) that are suitable to give less-contamination growing resources for Mycosphaerella. Subsequently, we analyze the three different media, i.e. potato dextrose agar, oatmeal agar, and V8 juice agar for the optimal growth of Mycosphaerella under varied photoperiod for incubation (12/12 light/dark cycle and 24-h dark) using the selected pH and antibiotics. This research was conducted in an ambient laboratory setting utilizing a complete randomized factorial design with ANOVA and Tukey test. The subculturing stage of Mycosphaerella was shown to be most successful at pH 6.0 with amoxicillin from a young infected leaf with first signs (brown streak without halo). This fungus preferred oatmeal agar with 24-hour dark incubation to achieve the highest mycelial growth (1.6 mm/day) and conidial production (3.3 x 10⁴ conidia ml^-1). This could be an essential approach employed by researchers to provide a sufficient quantity of Mycosphaerella propagules in vitro, in vivo, and ad planta trials for Sigatoka disease management.