Two-Sex Life Table Analysis for Optimizing Beauveria bassiana Application against Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae).

Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) is a highly dispersive, polyphagous insect pest that severely defoliates crops. Excessive reliance on synthetic insecticides leads to ecological pollution and resistance development, urging scientists to probe eco-friendly biopesticides. Here, we explore the virulence of an entomopathogenic fungus, Beauveria bassiana , against S. exigua , resulting in 88% larval mortality. Using an age-stage, two-sex life table, we evaluated the lethal and sublethal effects of B. bassiana on the demographic parameters of S. exigua , including survival, development, and reproduction. Sublethal (LC 20 ) and lethal concentrations (LC 50 ) of B. bassiana impacted the parental generation (F 0 ), with these effects further influencing the demographic parameters of the first filial generation (F 1 ). The infected F 1 offsprings showed a reduced intrinsic rate of increase ( r ), mean generation time ( T ), and net reproduction rate ( R 0 ). Larval developmental duration varied significantly between the control (10.98 d) and treated groups (LC 20 : 10.42; LC 50 : 9.37 d). Adults in the treated groups had significantly reduced lifespans (M: 8.22; F: 7.32 d) than the control (M: 10.00; F: 8.22 d). Reduced fecundity was observed in the B. bassiana -infected groups (LC 20 : 313.45; LC 50 : 223.92 eggs/female) compared to the control (359.55 eggs/female). A biochemical assay revealed elevated levels of detoxification enzymes (esterases, glutathione S-transferases, and acetylcholinesterase) in the F 0 generation after B. bassiana infection. However, the enzymatic activity remained non-significant in the F 1 generation likely due to the lack of direct fungal exposure. Our findings highlight the enduring effects of B. bassiana on the biological parameters and population dynamics of S. exigua , stressing its use in eco-friendly management programs.