Effects of pesticide application in insect pest control on alfalfa seed yield

Proper application of pesticide in insect pest control is essential for optimizing alfalfa (Medicago sativa) seed yield. This field experiment was designed to test the effects of pesticide application on alfalfa seed yield, yield components and insect pest. The results indicated that the treatment of applying pesticide at the budding stage and podding stage increased seed yield by 134%, and also significantly increased racemes per stem, pods per raceme, and seeds per pod, compared with CK (no pesticide application). And only applying pesticide at the budding stage decreased the negative effects of insect pest on seed yield, and led to higher seed yield than that of only applying pesticide at the podding stage. Correlation analysis revealed a significant positive relationship between racemes per stem and seed yield as well as between pods per raceme and seed yield under the treatments of pesticide application in insect pest control (P＜0.05).