Pathogenicity of some entomopathogenic fungi on wheat weevil Sitophilus granarius (L., 1758) (Coleoptera: Curculionidae)

In the present study, the toxicities of seven entomopathogenic fungal isolates, Beauveria bassiana (ARSEF-4984), Isaria farinosa (ARSEF-3580), Isaria fumosorosea (ARSEF-4501), Lecanicillium muscarium (ARSEF-5128), L. muscarium (ARSEF-972), Lecanicillium lecanii (TR38/11) and L. muscarium (Ve6), were tested against the adults of granary weevil, Sitophilus granarius (L., 1758) (Coleoptera: Curculionidae), under laboratory conditions (25 +/- 1 degrees C, 75 +/- 5% RH and 14h light:10h dark). Studies were conducted in Ataturk University (Erzurum, Turkiye), in 2018. Fungal isolates were sprayed to adults at two different conidial concentrations (1x105 and 1x107 ml-1). Mortality percentages were observed on the 2nd, 4th, 6th, 8th, and 10th days of treatment. A commercial isolate of L. muscarium were used as positive control and sterile water+0.25% Tween 20 used as negative control. The results demonstrated that the mortality rates of S. granarius adults treated with entomopathogenic fungi ranged from 1.01% to 98.9% across 10-day period. Higher concentration and longer exposure periods resulted in increasing virulence on the adult individuals. Among the strains tested, at 1x107 ml-1 concentration, I. fumosorosea, L. muscarium (ARFES-5128) and L. lecanii isolates displayed 97.85%, 94.62% and 93.58% cumulative mortalities respectively, on S. granarius adults by the 10th day of the experiment. These three isolates are regarded as highly promising biological control agents.