Entomopathogenic fungal strains as potential candidates for the management of red flour beetle, Tribolium castaneum (Tenebrionidea: Coleoptera), a potential pest of stored grains

Abstract

The red flour beetle, known scientifically as Tribolium castaneum, stands as a notorious pest afflicting stored grain commodities. The widespread reliance on chemical pesticides to curb its infestations poses a significant threat to human health, prompting several regions to reject shipments containing pesticides to safeguard human well-being and address environmental safety concerns. Acknowledging the drawbacks associated with chemical pesticides, the contemporary era is witnessing a shift towards chemical-free approaches, specifically towards biological methods, for the control of insect pests. In this context, the present investigation was formulated to tackle the infestation with entomopathogenic fungi, namely Beauveria bassiana, Metarhizium anisopliae, Verticillium lacanii, and Trichoderma viridea against the adult stage of the red flour beetle. Series of concentrations viz., 1 × 103, 1 × 105, 1 × 107, 1 × 109, and 1 × 1011 conidia/ml were used for treatment of wheat grains. Finding revealed that significant mortality percentage was observed at a concentration of 1 × 1011 conidia/ml after 12 days of exposure on all tested EPF strains. B. bassiana exhibited the highest efficacy with a 68% mortality followed by 63%, 41% and 39% on M. anisopliae, T. viridea and V. lacanii respectively after 12 days of exposure. The present study also reveals that B. bassiana and M. anisopliae after 12 days of exposure showed the lowest LC50 values, measuring 2.5 × 105 and 1.28 × 109 conidia/mL, respectively. Conversely, V. lacanni was adjudged to be the least efficacious with an LC50 value of 3.29 × 1010 conidia/mL. These results suggest that B. bassiana and M. anisopliae are potential candidates for biocontrol agents against the pest in question. This study presents a promising avenue for combatting pest infestations in stored grain commodities through the implementation of EPF.