Production of Entomopathogenic Fungi and Pathogenicity of Metarhizium anisopliae against Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

AIMS: To address the severe defoliation caused by the invasive bronze bug, Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae), this study investigated the mass production potential of three entomopathogenic fungal (EPF) strains and the specific biocontrol efficacy of Metarhizium anisopliae against this pest. METHODS AND RESULTS: Initially, Cordyceps javanica (LCBPF 11), M. anisopliae (LCBPF 31), and Beauveria bassiana (LCBPF 46) produced > 1 × 10⁹ conidia g⁻¹ in solid-state fermentation. To scale production, liquid culture was selected for C. javanica and M. anisopliae using industrial by-products (corn flour and molasses), while M. anisopliae was further compared in a rice flour-dextrose-yeast extract (M1) medium. Fitness assays revealed that while M. anisopliae blastospores (M1) were more heat-susceptible at 45°C (LT50 0.182 h) than aerial conidia (LT50 1.621 h), survival analysis of bioassays against T. peregrinus adults revealed highly significant differences among treatments. Remarkably, all M. anisopliae propagules achieved 100% mortality within five days, with blastospores produced in M1 medium reaching an LT50 of only 1.81 days. Furthermore, Cox proportional hazards modeling confirmed that these optimized blastospores (M1) presented a mortality risk 2.51 times higher than the commercial standard Metarril® (Hazard Ratio = 2.51; 95% CI: 1.90-3.31). CONCLUSIONS: To the best of our knowledge, this is the first report of M. anisopliae blastospores successfully infecting T. peregrinus. Taken altogether, these findings demonstrate the technical feasibility and significant potential of these rapid-acting infective propagules for the management of this forest pest.