Virulence of the entomopathogenic fungus Beauveria brongniartii to several life stages of the yellowish elongate chafer Heptophylla picea Motschulsky (Coleoptera: Scarabaeidae)

A strain of Beauveria brongniartii PBbr-1 was isolated from infected larvae of Heptophylla picea. This isolated strain attained 100% mortality of H. picea adults at a concentration of 1.0×107 conidia/ml, with a short median lethal time of 8.4 d for females and 7.0 d for males. The number of eggs laid by adults and percent of eggs hatching for females inoculated with PBbr-1 were lower than those by healthy females. However, when PBbr-1 was inoculated directly to the eggs, hatchability was almost the same as that in non-inoculated eggs. Since infected females appeared to lay eggs just before death, the eggs from females infected with PBbr-1 were thought to be unfertilized. Furthermore, PBbr-1 showed a high virulence to the first-stage larvae. PBbr-1 not only had a high virulence to the adults, but also suppressed subsequent generations. PBbr-1 is thus thought to be a very effective control agent for H. picea in combination with Beauveria amorpha HpBa-1.