Biological Characterization of Beauveria bassiana (Clavicipitaceae:Hypocreales) from Overwintering Sites of Sunn Pest, Eurygaster integriceps (Scutelleridae: Heteroptera) in Iran

Abstract

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