Determination of fungal pathogens and investigation of fungal agents of Hypera postica (Gyllenhall)

Hypera postica (Alfalfa weevil) (Col: Curculionidae) causes serious damage in alfalfa and a few closely related legumes. Despite the chemical, mechanical and biological methods, the damage of H. postica in the alfalfa fields is still continues seriously. In order to, determine an effective fungal agent against H. postica we 8 fungal strains had been isolated from field collected H. postica. After morphologic (infection pattern, colony morphology, spore shape) and molecular (ITS1-5.8S ITS2 gene area, EF1-α, Bloc, RPB1, sequences) characterizations, the isolates were identified as Beauveria bassiana (HpI-2, HpI-6, HpI-7, HpI-10, HpA-3, HpA-4, HpA-5) and Beauveria pseudobassiana (HpI-4). All isolates were isolated from H. postica for the first time. In addition, virulence of these isolates against H. postica was determined. Spore suspensions of 1×105, 1×106, 1×107, 1×108 conidia ml-1 were applied to both larvae and adults. The highest mortality for larvae were obtained from isolate HpA-5 (B. bassiana) with 100% mortality and HpI-4 (B. pseudobassiana) with 97% mortality within 14 days. The highest mortality for adults were obtained with isolates HpA-5 (B. bassiana) and HpI-4 (B. pseudobassiana) with 98% and 95% mortality within 14 days, respectively. These results are indeed promising, considering isolates with high virulence; they can be used for microbial and entegrated management against H. postica.