2.5 Production of inhibiting substances Production of diffusible and volatile substances, which have adverse effect on growth of C. gloeosporioides, were evaluated in separate trials. For diffusible substances, a dual culture was carried out on PDA plates incubating for 15 days at room temperature. Colony appearance of the pathogen, both on the test and control plates, was then observed and compared. For volatile substances, a 7-mm-diameter agar disc taken from a 10-day-old PDA culture of C. gloeosporioides was placed in the center of PDA plate. The yeast was inoculated by streaking on another PDA plate. The plate containing the pathogen was inverted over the plate of the yeast. Both plates were then sealed together with polyethylene film. For the control treatment, each plate of the pathogen was inverted over fresh PDA plate. There were ten replicated plates for each treatment. The test plates were incubated at room temperature. The diameter of C. gloeosporioides was measured at 10 days after incubation and compared to the control treatment.