biological characterization of beauveria bassiana (clavicipitaceae:hypocreales) from overwintering sites of sunn pest, eurygaster integriceps (scutelleridae: heteroptera) in iran

sunn pest is one of the most important cereal pests that affect both grain yield and quality of cerealin iran. one potential control strategy is to use entomopathogenic fungi such as beauveriabassiana vuillemin as mycoinsecticide to control this pest. naturally infested sunn pests inkermanshah province were collected and brought to laboratory. 10 isolates were selected forfurther analysis in the laboratory. isolate characters such as colony growth, conidia production,virulence and dose response were studied under laboratory conditions. colony growth increasedlinearly overtime at 27° c. isolate ir-k-43, ir-k-23 and ir-k-10 had the largest growth rate of3.6 mm/day. isolate ir-k-36 with 4.6×108 conidia/cm2 was the highest conidia producer. all ofthe selected isolates showed pathogenicity against eurygaster integriceps puton. five iranianisolates ir-k- 40, ir-k-58, ir-k-10, ir-k-53 and ir-k-43, and one turkish isolate spt 22 werehigh virulent isolates causing mortality ranging between 88.7–94.4 %. isolate ir-k-40 along withisolate spt 22 from turkey was selected for dose response study. the lethal concentrationrequired to kill 50% of insects (lc50) was 2.9×107 conidia/cm2 for both isolates. the results of thisstudy showed that b. bassiana can be isolated from sunn pest overwintering sites in kermanshah.in addition the selected isolates were pathogenic towards eurygaster integriceps puton underlaboratory conditions. these results will help in selection and development of these fungi for sunnpest, e. integriceps management in the future.