Surface hydrophobicity, viability and efficacy in biological control of Penicillium oxalicum spores produced in aerial and submerged culture

The surface hydrophobicity, viability and biocontrol ability of Penicillium oxalicum spores, produced either in aerial or submerged culture, were char acterized. A phase distribution test showed that spores produced in both me thods of culture were highly hydrophobic, but those produced in aerial cult ure were more hydrophobic. Spores stored fresh at either 4 or 25 degreesC r etained a high viability (80%) after 27 weeks of storage, although aerial s pores survived better. Freeze-drying severely affected viability, especiall y of submerged spores. Biocontrol ability against Fusarium oxysporum f. sp. lycopersici was studied in the growth chamber. Aerially- produced spores w ere more effective than submerged ones. Aerially-produced P. oxalicum spore s appeared to have more advantages than those produced by submerged culture , in relation to both viability and efficacy. These results demonstrate tha t physiological changes occur depending on production conditions which sign ificantly influences quality of the biocontrol agent.