STUDY ON THE LIFE TABLE AND ITS ANALYSIS OF PADDY STEM BORER ON THE EARLY RICE

The successive life table of paddy stem borer,Scir-pophaga incertulas (walker),on early rice in 1988-1990 were constructed in this paper,with the probability of effective eggs (=actual eggs/expected eggs),served as a linker of two generations By means of exclusion analysis method and exclusion index of population control (EIPC) from the data of the successive life tables,the probasbility of effective eggs of the 1st generation was an important factor affecting the population.In addition,the mortality of the larvae and pupae in overwintering generation also played an important role on the population trend.The overwintering adults laid the eggs on the rice seedings or on other places.But,the hatched larvae of this monophagous insect developed only on the growing rice.The egg period of 1st generation and the planting times of the early rice played an important role coordinately on the probability of effective eggs.It is a useful method for controlling paddy stem borer on early rice to regulate the coordination of the rice planting time with the egg period of 1st generation.The 1st-2nd generation of paddy stem borer developed in a relatively constant environment.By means of data in average successive life table,the effective egg density of the first generation may be used as the starting point to forecast the density of the 2nd generation of this insect