Residue Pattern And Diet Risk Assessment Of Deltamethrin,Sulfoxaflor And Flonicamid On Lonicerae Japonicae Flos

Lonicerae Japonicae Flos is one of the most widely used Traditional Chinese Medicines,possessing wide pharmacological actions,such as clearing heat and removing toxicity,antiphlogosis,anti-bacteria and antivirus.Diseases and pests occurred in Lonicera japonica Thunb.frequently and pesticides are the most wide and effective way to control them.But there are no pesticides registered in L.japonica,so farmers abused pesticide seriously.Therefore,three pesticide deltamethrin,sulfoxaflor and flonicamid are chose and the control efficiency,residue pattern,risk assessment and the effect on constituents were studied,and then established pesticide safe use methods in the standardized L.japonica planting.The results were as follows:1.The detection methods of deltamethrin,sulfoxaflor and flonicamid in Lonicerae Japonicae Flos were developed and validated.Deltamethrin in Lonicerae Japonicae Flos is extracted by acetone,purified florisil and detected by Gas chromatography-electron capture detector(GC-ECD).Sulfoxaflor is extracted by acetonitrile,purified by neutral alumina and detected by GC-ECD.Flonicamid is extracted by acetonitrile,purified by NH2 SPE column and detected by GC-ECD.The average recoveries of different spiked levels of three pesticides were 76.4%-86.9%,91.3%?96.7%and 81.5%?92.2%,with the RSD values ranged 5.0%?11%,0.6%?6.6%and 3.2%?6.6%,respectively.And limits of quantification(LOQs)of the methods were 0.05 mg/kg,0.05 mg/kg and 0.02 mg/kg,respectively.2.The control efficacies of sulfoxaflor and flonicamid were studied according to "NY/T 1464.27-2010 Pesticide guidelines for the field efficacy trials".The results show that the two pesticides have no phytotoxicity on Lonicera japonica Thunb.and good efficacy on controlling aphids.The dose of sulfoxaflor and flonicamid is 1.5 g/mu and 4 g/mu,respectively.3.Field experiments was conducted according to "ny/t 788-2004 pesticide residue filed experiment practice" in Fengqiu,Henan Province in 2015 and 2016 to investigate the dissipation of deltamethrin,sulfoxaflor and flonicamid.The results during two years indicated that the dissipation of the three pesticides in Lonicerae Japonicae Flos were all fitted into first order dissipation kinetics;the half-life of deltamethrin sulfoxaflor,flonicamid was 1.95?2.24 d,1.27?1.55 d,was 2.99?3.22 d.4.The final residues of deltamethrin,sulfoxaflor and flonicamid in Lonicerae Japonicae Flos were studied.The final residue of the three pesticides were ND?0.82 mg/kg,ND?0.35 mg/kg and 0.023?1.5 mg/kg.And the pre-harvest intervals of deltamethrin,sulfoxaflor and flonicamid are 4 d,9 d and 15 d according to the risk assessment and MRLs.5.The effect of three pesticides on the typical constituent content of Lonicerae Japonicae Flos were studied.The results showed that as for chlorogenic acid and galuteolin,there was no difference after application of deltamethrin and sulfoxaflor;the content of galuteolin was decreased significantly(P<0.01)and the content of chlorogenic acid showed no significant difference after flonicamid application.And deltamethrin affected two,sulfoxaflor affected one and flonicamid affected four constituents after pesticides application.6.The safe use methods of pesticide on L.japonica were put forward according the above results:? Deltamethrin:spray 25 g/L deltamethrin missible oil at 0.5 g/mu less than twice to control aphid and the pre-harvest intervals are 4 d.? Sulfoxaflor:spray 50%sulfoxaflor water dispersible granule at 1.5 g/mu less than twice to control aphid and the pre-harvest intervals are 9 d.? flonicamid:spray 10%flonicamid water dispersible granule at 4 g/mu less than twice to control aphid and the pre-harvest intervals are 15 d.And it can be only used when not collecting flowers.