The Parasitic Selectivity of Aphidius gi f uensis to Myzus persicae and Lipaphis erysimi

A phidius gifuensis is an important parasitoid to some aphids .In this research ,the parasitic selectivity of A. gifuensis to Myzus persicae and Lipaphis erysimi was studied ,in which the parasitic situation ,selectivi‐ty ,preference and switching behavior of the parasitoids were analyzed .The total sampling size was 60 a‐phids and the ratios of M. persicae individuals to L. erysimi individuals were 1∶5 ,2∶4 ,3∶3 ,4∶2 or 5∶1 .The test result showed that A. gif uensis had more oviposition in M. persicae than in L. erysimi , and that the parasitic ratio of A. gif uensis to M. persicae or L. erysimi was positively correlated with the aphid density ,and the total parasitic function of A. gi f uensis to M. persicae and L. erysimi group was higher .A. gif uensis showed a positive preference to M. persicae and a negative preference to L. ery‐simi .and a negative switching to M. persicae and a positive switching to L. erysimi .