Abstract: The aggregation and dispersion behaviors of Macrosiphum avenae and Rhopalosiphym padi are studied on wheat fields in Luohe county of Henan province, with the method of population spatial pattern investigation.The results show that these two species have the same seasonal aggregation peaks, i.e., in early April and mid-May, in their successive dispersion processes. Although the spatial pattern of the two aphid populations are similar among wheat plants, their aggregation and dispersion are obviously different among different parts of the plant,as the result of natural selection and adaptation. Basic principles are put forward for the rational control of wheat aphid.

Key words: rhizosphere, antimicrobial spectrum, BOXAIR-PCR, 16S rDNA, diversity