To obtain extracellular filtrates with antifungal activity, 500 mL of PDB were inoculated to obtain an absorbance of 0.2 at 600 nm with an overnight culture of each strain in PDB, and then incubated at 28 C and 180 rpm. Samples of 5 mL were taken at 12, 24 and 60 h, which corresponds to the logarithmic, stationary, and late stationary phases of growth of each strain, and were centrifuged at 8000 rpm. The supernatants (extracellular fraction) were sterilized in an autoclave. Then 200 ll was added to small bottomless tubes placed on the surface overlaid with S. reilianum, and inoculated in YEPD plates as described above. The plates were incubated at 28 C for 120 h and observed every 12 h. The filtrates with antifungal activity were those that inhibited the development of the
fungus. In this case, inhibition halos were observed, which were
measured in mm. For the control, 200 ll of PDB medium ware
added.
2.4. Field test