The study has been based on both the model for rice population growth and the model for simulating population life system of lice case worm. By coupling a correlative model of the lice and the insect pest, the dynamics of the rice lice case worm natural enemy system was simulated day by day,the rates of yield loss being assessed under different conditions. Further by economic accounting, the poly dimentional and dynamic economic threshold was determined. In light of the holistic ecosystem in rice field, a f...