Isolation and biological characterization of Beauveria bassiana from overwintering sites of Sunn Pest, Eurygaster integriceps, in Kermanshah Province, Iran

Sunn pest is one of the most important cereal pests that affect both grain yield and quality of cereal in Iran. One potential control strategy is to use entomopathogenic fungi such as Beauveria bassiana Vuillemin as mycoinsecticide to control this pest. Naturally infested Sunn pests in Kermanshah province were collected and brought to laboratory. 10 isolates were selected for further analysis in the laboratory. Isolate characters such as colony growth, conidia production, virulence and dose response were studied under laboratory conditions. Colony growth increased linearly overtime at 27° C. Isolate IR-K-43, IR-K-23 and IR-K-10 had the largest growth rate of 3.6 mm/day. Isolate IR-K-36 with 4.6×108 conidia/cm2 was the highest conidia producer. All of the selected isolates showed pathogenicity against Eurygaster integriceps Puton. Five Iranian isolates IR-K- 40, IR-K-58, IR-K-10, IR-K-53 and IR-K-43, and one Turkish isolate SPT 22 were high virulent isolates causing mortality ranging between 88.7–94.4 %. Isolate IR-K-40 along with isolate SPT 22 from Turkey was selected for dose response study. The lethal concentration required to kill 50% of insects (LC50) was 2.9×107 conidia/cm2 for both isolates. The results of this study show that B. bassiana can be isolated from Sunn pest overwintering sites in Kermanshah. In addition the selected isolates were pathogenic towards Eurygaster integriceps Puton under laboratory conditions. These results will help in selection and development of these fungi for Sunn pest, E. integriceps management in the future.