二化螟危害水稻的产量损失与防治指标研究

Yield Loss of Rice caused by Rice Stem Borer and the Threshhoid of Economic injury

二化螟危害分蘖力强的杂交稻时,水稻营养生长危害重,产量损失较轻;但在生殖生长期危害轻,则产量损失较重。以产量损失2％为经济允许水平定论,其防治指标分别为:分蘖期每亩有卯140块或枯心率3％或枯鞘率7％:孕穗、抽穗期,当白穗率出现1.8％时应立即防治。

The rice stem borer ( RSB ) Chilo suppressalis has been a serious pest on rice in Henan Province. The yield loss of rice caused by this pest and the threshhold of economic injury was studied in 1984, The results of this study can be summarized as followst1 .When hybrid rice was injuried by the RSB larvae hatched from individaul egg-mass,the injury percentage of rice is higher in the nutrient stage of rice than in the reproductive stage) However, the yield loss of rice is higher inthe reproductive stage of rice than in the nutrient stage,2 . If economic injury level was set as 2 %yield loss of rice, the control threshholds are, 140egg-mass per mu or 3 %dead heart in the tillering stage}1 ,78% white ear jn the heading stage respectively