The stylet penetration behavior of aphids when feeding on plants is associated with virus acquisition and inoculation.Aphidius gifuensis (Ashmead) is a primary endoparasitoid ofMyzus persicae (Sulzer) which is the most efficient vector of plant viruses.Information about the effects ofparasitoid on aphid and virus transmission can provide an essential foundation for designing effective biological control strategies.This study aimed to investigate the effects ofA.gifuensis on the feeding behavior and potato virus Y (PVY)transmission ability of M.persicae.The results showed that after M.persicae was parasitized by A.gifuensis,the duration of the first probe significantly decreased.Additionally,A.gifuensis exerted remarkable effects on aphid feeding in phloem ingestion.The contribution of the El waveform to the phloem phase was significantly higher in all parasitized aphids than in the control group.Although the time of infestation increased for parasitized aphids,the total duration of phloem sap ingestion decreased.Interestingly,the percentage of time M.persicae spent in the xylem and phloem phases only changed significantly on day 5.The percent transmission of PVY by the aphids parasitized on day 5 was lower than that in the control,but no significant differences were detected.The significance of this work is the demonstration that A.gifuensis can impede the feeding behavior of M.persicae,which sheds light on the biological basis ofA.gifuensis as a natural enemy,but unfortunately does not provide an immediate solution for disrupting the transmission of PVY.