Abstract: This paper is an introduction of the functions of soil animals which participate either in the disintegration and chemical weathering of parent materials or in the decomposition of dead organisms in soil within a terrestrial ecosystem.The formation of horizons in soil is a an important background for collecting or studing soil animals. The fauna in mature and undisturbed soils shows a quantitative and qualitative vertical stratification.Many soil animals can accumulate certain substances in their bodies only in small amounts. This could also be of importance in soil, contributing most effective decompositing environment to terrestrial ecosystem.

Key words: Zoophthora anhuiensis, Myzus persicae, Virul ence, Latent period, Fecundity, Intrinsic increase rate