Abstract

The development of fungal biopesticides requires the efficient production of large numbers spores or other propagules. The current study used published information concerning carbon concentrations and C:N ratios to evaluate the effects of carbon and nitrogen sources on sporulation of Paecilomyces lilacinus (IPC-P and M- 14) and Metarhizium anisopliae (SQZ-1-21 and RS-4-1) in a two-stage cultivation system. For P. lilacinus IPCP, the optimal sporulation medium contained urea as the nitrogen source, dextrin as the carbon source at 1 g/L, a C:N ratio of 5:1, with ZnSO4·7H2O at 10 mg/L and CaCl2 at 3 g/L. The optimal sporulation medium for P. lilacinus M-14 contained soy peptone as the nitrogen source and maltose as the carbon source at 2 g/L, a C:N ratio of 10:1, with ZnSO4·7H2O at 250 mg/L, CuSO4·5H2O at 10 mg/L, H3BO4 at 5 mg/L, and Na2MoO4·2H2O at 5 mg/L. The optimum sporulation medium for M. anisopliae SQZ-1-21 contained urea as the nitrogen source, sucrose as the carbon source at 16 g/ L, a C:N ratio of 80:1, with ZnSO4·7H2O at 50 mg/L, CuSO4·5H2O at 50 mg/L, H3BO4 at 5 mg/L, and MnSO4·H2O at 10 mg/L. The optimum sporulation medium for M. anisopliae RS-4-1 contained soy peptone as the nitrogen source, sucrose as the carbon source at 4 g/L, a C:N ratio of 5:1, with ZnSO4·7H2O at 50 mg/L and H3BO4 at 50 mg/L. All sporulation media contained 17 g/L agar. While these results were empirically derived, they provide a first step toward low-cost mass production of these biocontrol agents.

• Keywords: M. anisopliae; P. lilacinus; nutrition; sporulation