Effects of Beauveria bassiana on Tenebrio molitor (Coleoptera: Tenebrionidae) and its impact on catalase and glutathione S-transferase enzymes

Abstract

This study employed the insect bait method to isolate native entomopathogenic fungi (EPF) from soil samples. Additionally, the research examined fungi pathogenicity against different life stages of Tenebrio molitor respond to these native isolates in a laboratory setting. Results showed that isolated EPF was identified as Beauveria bassiana based on molecular techniques. The results of the insecticidal bioassay demonstrated that B. bassiana exhibited high pathogenicity against larvae (82.66 %), pupae (97.33 %), and adults (65.33 %). Among the developmental stages, the pupae were the most susceptible to B. bassiana at 9 days post-treatment. The probit analysis revealed low LC₅₀ and LC₉₀ values for larvae (1.8 × 10ˆ5 and 6.4 × 10ˆ10 conidia/mL), for pupae (2.7 × 10ˆ4 and 1.1 × 10ˆ8 conidia/mL), and for adults (1.3 × 10ˆ7 and 2.2 × 10ˆ16 conidia/mL). The biochemical enzyme analysis clearly showed that levels of the catalase enzyme decreased (1.53–0.7 μg/mL) at the highest concentration (1 × 10ˆ9 conidia/mL). In contrast, glutathione S-transferase enzyme levels increased (up to 8.3 μg/mL) at higher concentrations (1 × 10ˆ9 conidia/mL). However, higher doses of B. bassiana conidia showed enzyme more alterations in the larvae. This study clearly concluded that B. bassiana is a promising, cost-effective, pollution-free, and target-specific candidate for controlling the various developmental stages of T. molitor.