Efficacy of Beauveria bassiana Ric1 in controlling Zophobas morio larvae: A promising biological approach

Abstract

The study aimed to evaluate the efficacy of entomopathogenic fungi for the biological control of Zophobas morio (Fabricius, 1776) to prevent economic losses in packaged amylase food products. This study aimed to evaluate the potential of the entomopathogenic fungus Beauveria bassiana Ric1 as a biological control agent against Z. morio. The B. bassiana Ric1 isolate was cultured on Sabouraud Dextrose Agar (SDA), displaying white colonies with irregular edges and producing spherical conidia. Phylogenetic analysis using ITS gene sequences confirmed the isolate's close relation to other B. bassiana strains. Z. morio larvae were exposed to five different conidial concentrations of B. bassiana Ric1 to determine its virulence. The experiments were conducted in triplicate with each group consisting of ten healthy 3rd instar Z. morio larvae. Conidial suspensions at the two highest concentrations (1 × 10⁸ and 1 × 10⁹ conidia/mL⁻¹) resulted in 100% larval mortality within four days. Additionally, 1 × 10⁷ and 1 × 10⁶ conidia/mL⁻¹ concentrations achieved 100% mortality on days six and seven, respectively. The lowest concentration (1 × 10⁵) led to 50% mortality by the end of the bioassay. To confirm that B. bassiana Ric1 caused larval death, the cadavers were incubated on moist paper at room temperature for five days. Mycosis rates of 100% were observed at concentrations of 1 × 10⁸ and 1 × 10⁹, while concentrations of 1 × 10⁷, 1 × 10⁶, and 1 × 10⁵ conidia/mL⁻¹ resulted in mycosis rates of 90%, 80%, and 40%, respectively. The LC₅₀ value of B. bassiana Ric1 was calculated to be 2.06 × 10⁵ conidia/mL⁻¹ for Z. morio larvae. These results indicate that B. bassiana Ric1 is a promising biocontrol agent against Z. morio.