A preliminary model to simulate the effect of insecticides on a spider‐leafhopper system in the paddy field

Abstract

Summary On the basis of life‐table studies of the green rice leafhopper, Nephotettix cincticeps Uhler , a descriptive model was constructed to simulate the life system of leafhoppers in the paddy field. Computer simulation demonstrated the existence of an optimum ratio of predators to prey in utilization of spiders for the control of leafhoppers. Also the population density of Lycosa which prey upon leafhoppers appears to determine the feasibility of controlling leafhoppers with reduced number of applications of selective insecticides. The increase of leafhoppers after application of non‐selective insecticides was also simulated by the proposed model.