Potential Efficiency of Aspergillus chevalieri Against Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) Larvae: Conidial Suspension and Ethanol Extract

In recent years, there has been a notable increase in research data supporting the use of fungal species from diverse genera such as Penicillium, Aspergillus, Fusarium, Beauveria, Cordyceps, Metarhizium, and Purpureocillium in biological control applications. The current study was conducted to identify Aspergillus chevalieri using morphological characteristics and molecular data, then to determine the potential efficiency of conidial suspension and ethanol extract against Ephestia kuehniella and to investigate its mycotoxin production potential and cytotoxicity. The identification was carried out using phenotypic characteristics and sequences of the internal transcribed spacer (ITS), beta-tubulin gene (benA), and RNA polymerase II second largest subunit (RPB2) loci. In developmental biology studies, it was determined that topically applied conidial suspensions and ethanol extracts at varying concentrations affected different life stages of the insect. In the conidial suspension treatments, the larval period (at 10⁸ conidia/mL) and pupal period (at 10⁶, 10⁷, and 10⁸ conidia/mL) were notably shortened compared to the control group. In ethanol extract applications, the adult emergence time was reduced at the lowest concentrations (0.5 mg/mL and 1 mg/mL). Furthermore, both conidial suspensions and ethanol extracts caused a significant decrease in the total number of eggs, depending on the concentration applied. In the cytotoxicity test, the ethanol extract of the fungus was found to be cytotoxic in the L929 mouse cell line (NCTC clone 929) at concentrations above 0.78 mg/mL. This study showed that the fungus does not produce aflatoxin and ochratoxin and provided the first information on its potential efficiency against E. kuehniella larvae. Based on the present findings, A. chevalieri can be considered a promising candidate for inclusion in biological control programs. To fully assess its potential, future studies should explore its efficacy against a broader range of pest species and conduct field trials under diverse environmental conditions to validate the laboratory results.