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The objective of this study was to evaluate the pathogenicity of Metarhizium anisopliae (Ma) and Beauveria bassiana (Bb) isolates, obtained from adult Ctenocephalides canis, the dog flea, under laboratory conditions. Nine, monosporic cultures were isolated. Each were pathogenic when exposed by immersion at a concentration of 1x108 conidia/ml, causing between 10-100% mycosis at ten days post-inoculation. Four isolates identified as Bb9, Bb6, Ma9 and Ma10, were the most pathogenic as mycosis reached 100%, which places them as potential candidates to be used as biological control agents. [ABSTRACT FROM AUTHOR]

This chapter describes the production of conidia by Metarhizium anisopliae using solid-state fermentation. Before production of conidia, procedures for strains conservation, reactivation, and propagation are essential in order to provide genetic stability of the strains. The strain is conserved in freeze-dried vials and then reactivated through insect inoculation. Rice is used as a substrate for the conidia production in two different bioreactors: plastic bags and tubular bioreactor. The CO2 production in the tubular bioreactors is measured with a respirometer; this system allows calculating indirect growth parameters as lag time (tlag) (25-35 h), maximum rate of CO2 production (rCO2 max) (0.5-0.7 mg/gdm h), specific rate of CO2 production (μ) (0.10-0.15 1/h), and final CO2 production (CO2) (100-120 mg/gdm). Conidial yield per gram of dry substrate (gdm) should be above 1 × 10(9) conidia/gdm after 10 days of incubation. Germination and viability of conidia obtained after 10 days of incubation should be above 80 % and 75 %, respectively. Bioassays using of Tenebrio molitor as a host insect should yield a final mortality above 80 %.