棉田烟粉虱的为害及其经济阈值分析

【目的】 研究烟粉虱对棉花为害性及棉田烟粉虱的防治指标,为棉田烟粉虱防控提供理论依据。【方法】 采用田间试验、田间烟粉虱虫量系统调查、棉花产量测定的方法,分析烟粉虱对棉花为害性及防治数据,建立棉田烟粉虱的经济阈值。【结果】 烟粉虱对棉花单株结铃数、单株籽棉重、皮棉单产等均有明显的影响,但对单铃重没有明显的影响;虫口密度(x)与棉花单株结铃数(Y₁)、单株籽棉重(Y₂)、皮棉单产(Y₃)等指标的回归方程分别为:Y₁= 12.242 e^{-0.008 x} (r = 0.912 7^**),Y₂= 29.07e^{-0.009 6x} (r=0.894 4^**),Y₃= 29.07 e^{-0.009 6x}(r=0.894 4^**),虫口密度与棉花单株铃重、衣分没有明显的相关关系。烟粉虱对棉花纤维长度有明显影响,虫量与棉花纤维长度(Y₄)回归方程为:Y₄ = -0.004 6x + 28.409 r=0.607^*。【结论】 烟粉虱影响棉花产量和品质。棉田烟粉虱的经济和阈值以若虫计为1.9头/cm²。

Study on the Damage of Bemisia tabaci to Cotton and the Economic Threshold in Cotton Fields

【Objective】 The project aims to investigate the damage of Bemisia tabaci to cotton and the control index in order to provide theoretical basis for the scientific prevention and control of cotton B. tabaci. 【Method】 Through the field trials,the systematic investigation of B. tabaci and the determination of cotton yield,etc. the damage of B. tabaci to cotton was conducted, and then on this basis, the economic threshold of Bemisia. tabaci in cotton fields was set up.【Result】 B. tabaci damage to cotton had significant effects on cotton boll number per plant, seed cotton weight per plant, seedless cotton yield per mu, but no significant influence on average boll weight. The regression equations of pest density with cotton boll number per plant, seed cotton weight per plant, seedless cotton yield per mu were Y₁= 12.242 e^{-0.008 x} (r = 0.912 7^**),Y₂= 29.07 e^{-0.009 6x}(r=0.894 4^**),Y₃= 29.07 e^{-0.009 6x}(r=0.894 4^**), respectively, but there was no significant correlation between pest density with average boll weight and cotton gin turnout. There was significant effect of B. tabaci on cotton fiber length with the regression equations :Y₄ = -0.004 6 x + 28.409 r=0.607^*.【Conclusion】 The damage of B. tabaci affects both the cotton yield and the quality. The economic threshold of B. tabaci is 1.9 nmyph/cm²