Abstract: Thirteen pesticides at different concentrations were sprayed on snap bean(Phase-vlas pulgaris) leaves in laboratory to test the mortality of A.fallacis,by which,sublethal concentrations (LC0-10) were determined.Effects of different sublethal concentrations on the reproduction and settlement of A.fallacis are summarized as follows:alphacypermethrin,fen-propathrin,cypermethrin,kungfu,talastar,ambuectin and bayleton reduce the predator's fecundity as well as its settlement ratio on snap bean;omethoate affects the predator's settlement,propargite affects its fecundity;nissorun,amitraz,cascade and apollo do not show obvious effects on the predator,they are safe to A.fallacis.Small amount residue of the pesticides on host plant can seriously affect the fecundity and settlement of A.fallacis,to which much attention should be paid in harmonizing relations between chemical control and biological control.

Key words: Amblyseius fallacis, Sublethal concentration, Pesticide, Reproduction, Settle-ment