Efficacy of entomopathogenic fungi for the management of Trogoderma granarium Everts on wheat grains

Abstract

AbstractFour species of Trichoderma genius (T. harzianum, T. citrinoviride, T. viride and T. asperellum) and Metarhizium anisopliae were assessed for their effects on larval mortality and progeny production of Trogoderma granarium Everts (Coleoptera: Dermestidae). The fungal strains were tested at 2.0 × 106, 2.0 × 107, 2.0 × 108 and 2.0 × 109 spores/kg. The larval mortality of T. granarium was recorded after 7, 14 and 21 days of treatment. The emerged adults (F1) from treated larvae were counted after 30 days of treatment, while F2 and grain weight loss were examined after 80 days of treatment. In general, increasing of spore concentration of all fungal strains enhanced the larval mortality. After 21 of treatment, all fungal strains induced notable larval mortality particularly at the highest concentration (2.0 × 109 spores/kg) except T. viride (19.4%). The highest larval mortality was observed in treatments with M. anisopliae (82.1%) and T. citrinoviride (69.0%) at 2.0 × 109 spores/kg, respectively. Furthermore, all spore concentrations of tested fungi decreased the emerged adults (F1 and F2) with M. anisopliae, T. citrinoviride and T. harzianum being the most potent, particularly at 2.0 × 109 spores/kg. After 80 days, M. anisopliae and T. citrinoviride at 2.0 × 109 spores/kg induced the highest protection of wheat grains against larvae of T. granarium with weight loss of 0.7 and 1.3%, respectively. The outcomes of the present study indicate that the two fungi, M. anisopliae and T. citrinoviride are highly effective seed protectants against T. granarium and could be applied in the integrated pest management programs (IPM) of khapra beetle as effective biological control agents.