Abstract: In this paper, the method of insect population dynamic simulation has been improved, which integrates some advantages of population models that have been published. Based on the population simulation model of paddy stem borer Tryporyza incertulas (Walker) (PSB) and yield loss rate forecasting model of rice crop,she optimal management decision problem of PSB population was studied with theaim to obtain maximal net revenue. The net revenue was influenced by several control strategies and their combinations such as adjusting the time of seedling transplantation, using resistant rice varieties, protecting and utilizing natural enemiesand application of insecticides. The system model can provide on optimal decision strategy to effectively control PSB population, which contains measures of agricultural control, biological control and chemical control.

Key words: Tryporyza incertulas (Waker), population life system, optimal mana- gement decision