Abstract: Studies on the predatory selectivity of Harmonia axyridis show that it has a positive preference to Hyalopterus amygdali, but a negative one to Erythroneura sudra. When one of these preies exists alone, the functional response of H.axyridis shows the HollingⅡtype. When both of them exist simultaneously, but one′s density is less,the functional respones of H. axyridis on another prey still shows the Holling Ⅱ type.If one prey has a higher density. the functional response of H. aryridis shows the Holling Ⅱ type on E.sudra,but the Holling Ⅱ type on H. amygdali.

Key words: Harmonia axyridis, Hyalopterus amygdali, Erythroneua sudra, Predator, plastic film mulching, soil net nitrogen mineralization, resin core culture method, summer maize