【摘要】 为明确五（２）代白背飞虱对粳稻的为害损失，确定合理的防治指标， 作者于１９９６～１９９７ 年在中、晚粳水稻品种武育粳 ３ 号和 Ｓｏ１５ 上，通过接虫笼罩法结合小区、大田试验，研究不同虫量对水稻产量的影响以及五（２）代白背飞虱的增殖规律、为害损失和防治指标⒚结果表明，中、晚粳稻不同生育期，不同虫口密度的白背飞虱的增长速度不一样⒚同一生育期，低密度的增殖速度要大于高密度，但总虫量高密度处理显著高于低密度区⒚五（２）代白背飞虱百丛虫量与水稻产量损失呈极显著正相关⒚因此，当五（２）代白背飞虱早发或中等以上发生时，必须用药防治⒚控制其危害，防治指标为 １８０～２５０ 头⒚更多还原

【Abstract】 A field trial was performed to estimate the damage to Japonica (Wuyujing 3) by the second generation population of the white backed planthopper , Sogatell furcifera(Horvath),and the economic threshold for the pest The results showed that the increase of the population differed among the treatment with varying levels of initial infestation Higher reproductive potential was observed in the treatments with lower levels of infestation though the density was eventually greater in the plots infested at higher densities The yield loss was significantly correlated with the population density. The economic threshold was thus estimated to be 180 250 planthoppers per 100 hills This suggests that spray is needed when the second generation population infests the crop earlier at a medium level更多还原