EFFECT OF MEAN DENSITY AND AGGREGATION OF THE WOOLLY APPLE APHID (ERIOSOMA LANIGERUM HAUSM.) ON PARASITISM PERCENTAGE OF APHE LINUS MALI HALDEMAN
苹果绵蚜密度及聚集度对日光蜂寄生作用的影响

This paper dealt with the effect of mean density and aggregation of woolly apple aphid on parasitism percentage of Aphelinus mali, Haldeman. The results showed that parasitism percentage of A. mali gradually decreased with the increasing mean density and aggregation of woolly apple aphid. Their empirical models are as follows: Ln P = 4.75-1.03 Ln M R= -0.761 (P<0.05) Ln P = 5.98-0.915 Ln C R= -0.792 (P<0.05) Ln P = 6.19-0.99Ln M R= -0.812 (P<0.05) Where P is parasitism percentage of A. mali; M is mean density of woolly apple aphid; C is index of Poisson distribution; M is mean crowding of woolly apple aphid; R is correlation coefficient.