Screening of synergistic mixture of lambda-cyhalothrin and nitenpyram and its field control efficacy on wheat aphid
In order to delay insecticides resistance and reduce the usage of insecticides during wheat aphid control,this study screened out the synergistic mixing ratio of lambda-cyhalothrin and nitenpyram against wheat aphid,and further examined the field control efficacies of the mixture against wheat aphid.The results of leaf dipping method showed that the LC50 value of lambda-cyhalothrin to wheat aphid was 25.01 mg/L,and the that of nitenpyram was 28.21 mg/L.Synergistic mixing ratio tests showed that the mixtures of lambda-cyhalothrin and nitenpyram with ratio of 1.3∶1,1∶1.1,1∶1.7 and 1∶10.2 exhibited the synergistic effects on wheat aphid with toxicity ratio of 1.28,1.49,1.64 and 1.50,respectively.Further study showed that the active ingredients combination of lambda-cyhalothrin and nitenpyram at ratio of 1∶4.5,1∶7.5 and 1∶10.2 exhibited significant synergistic effects with high co-toxicity coefficient.When the active ingredient ratio of lambda-cyhalothrin and nitenpyram at 1∶7.5,the LC50 value of the combination was 5.22 mg/L,and the co-toxicity coefficient reached 532.61.Field test was carried out with the combination of lambda-cyhalothrin 10％EW and nitenpyram 20％SL at an active ingredient ratio of 1∶7.5.There was no significant difference in the control efficacies of the mixture against wheat aphids with the lambda-cyhalothrin.One day after treatment,the control efficacy of the mixture was higher than that of the nitenpyram,while three days and seven days after treatments,there was no difference in the control efficacies of the mixture and nitenpyram.After treatment,the control efficacies of the mixture increased within seven days,while it reached 92.98％at the 7th day,which ensures the control efficacies to wheat aphid with achieving the purpose of reduction the usage of lambda-cyhalothrin.
NETL
NSTL
万方数据
