Abstract: By means of single and mixed inoculation,this paper studied the interspecific competition between T.confusum and T.pretiosum on the factitious eggs of Corcyra cephaloica under different parasitoid densities,host densities and inoculated spaces.The results showed that for both singly and mixed inoculated groups,the parasitism increased with parasitoid density but decreased with host density,whereas the percentage of female progeny dropped with parasitoid density but enhanced with host density.No significant effect was observed on adult emergence for all parasitoid and host density treatments.In mixed inoculated group,the proportion of T.pretiosum in the progeny decreased with parasitoid density but increased with host density,and was more than 50% in all treatments,indicating that T.pretiosum had a stronger competitive ability than T.confusum.In the spaces ranging from 4 cm³ to 102 cm³,the parasitism decreased gradually in both singly and mixed inoculated groups.The percentage of female progeny and adult emergence had no significant difference among different inoculated spaces.In mixed inoculated group,the proportion of T.pretiosum in the progeny was more than 50% in all treatments except space 102 cm³,but decreased with space,which suggested that T.confusum could improve their competitive ability through increasing their search areas and looking for more hosts.

Key words: Trichogramma confusum, T.pretiosum, Corcyra cephaloica, Interspecific competition