Abstract: Entomophthoralean fungi and Aphidiidae are important obligate aphid biocontrol agents and co-exist in the field ecosystem. Here, the interaction between Pandora neoaphidis and Aphidius gifuensis, which are representatives of Entomophthoralean fungi and Aphidiidae, respectively, was studied in alate population of green peach aphid (Myzus persicae). The alates were submitted to treatments in which the aphids were inoculated with P. neoaphidis prior to expose to A. gifuensis at different time intervals. It was found that there were significant differences in the infection rate (all are greater than 60%) between the treatments. However, the parasitism rates (all are less than 15%) were not different between the treatments. To the contrary, when the alates were submitted to treatments in which aphids were exposed to A. gifuensis prior to inoculation with P. neoaphidis at different time intervals, there were significant differences in the parasitism rate and the infection rate between the treatments. In addition, the parasitism rate and infection rate of the 4-day-interval treatment showed obvious difference from other treatments. The results suggest that P. neoaphidis has certain competition advantages over A. gifuensis in the aphid population under laboratory conditions. However, their interactions are not substitutional, but iterative. This study provides a new evidence for the combination of obligate aphid-pathogenic fungi (especially Entomophthoralean fungi) with Aphidiidae in the biological control of aphids.

Key words: Pandora neoaphidis, Aphidius gifuensis, interaction, alates