1 Selection of Beauveria isolates pathogenic to adults of

3These authors contributed equally to this work The brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae), is a destructive inva-sive pest and has become one of the most economically-important rice pests in China. Effective control measures are desperately needed. Entomopathogenic fungi, such as Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Clavicipitaceae) and B. brongniartii (Saccardo), have shown great potential for the management of some sucking pest species. In this study, to explore alternative strategies for sustainable control of the sucking pest population, nine isolates of Beauveria from different pests were bioassayed under the concentrated standard spray of 1000 conidia/mm2 in laboratory. The cumulative mortalities of adults ranged from 17.2 to 79.1 % 10 days after inoculation. The virulence among all tested isolates exhibited significant differences (at p = 0.05). The highest virulent isolate was Bb09, which killed 79.1 % of the treated insects and had a median lethal time of 5.5 days. Its median lethal concentration values were estimated as 134 conidia/mm2 on day 10. The chitinase activities of nine isolates were also assayed. The re-sults showed that the chitinase activity (18.7 U/mg) of isolate Bbr09 was the highest among al