Abstract:

Ormyrus coccotori (Hymenoptera: Ormyridae) is a parasitoid of gall-making weevil Coccotorus chaoi (Coleoptera: Curculionidae) feeding on young twigs of bunge hackbreey tree. Its biology and relationship with the host were observed in lab and woods. The results showed that the species is a single ecto-parasitoid of mature larva of the gall-making weevil. It developed two generations per year, and overwintered as mature larva inside the host gall, pupated in later May next year. The whole life history accomplished in the gall. Its parasitism rate was 13.7% in Shandong totally, and in Beijing it was 30.7 % in the second generation. Meanwhile, the parasitoid was two generations while its host only one generation per year, I.e. it can parasitize twice one generation larvae of the host weevil. So one may say that the parasitoid play an important role to control the population of the weevil, and it is a dominant natural enemy agent for biological control the insect pest.

Key words: Ormyrus coccotori, biology, Coccotorus chaoi, parasitism relationship, biological control