虫数栽植密度及施氮量对水稻二化螟危害的影响研究

EFFECTS OF THE POPULATION OF RICE STEMBORER,RICE PLANT DENSITY AND N FERTILIZER ON THE INJURY OF THE CROP BY THE PEST

The levels of injury caused by Chilo suppressalis(Walker)to rice plants are closely re-lated to the population density of the pest,the density of the rice plants and N application,the first factor being predominant.When all three factors reach high level,severe injury willnormally result.In contrast,lower population of both the pest and the crop accompaniesby adequate fertilization tend to give a high yield.In the rice-producing regions where inju-ry frequently occurs,emphasis of pest control is recommended to be placed on earlyplantedfields with plentiful fertilizer and high pest density so as to gain better economical,ccological and social benefits.