Residual Behavior Of Chlorantraniliprole And Fludioxonil In Dendrobium Officinale Kimura Et Migo And Soil

Dendrobium officinale Kimura et Migo,as a famous herb medicine,is loved by lots of people because of enhancing immunity and antioxidant activity.In the process of growing,Den.drobium officinale Kimura et Migo is vulnerable to pests and diseases which could reduce quality and yield.Chlorantraniliprole is an insecticide to control Spodoptera litura Fabricius and fludioxonil is a fungicide to control gray mold.For the evaluation on the safety of pesticide application,studies were conducted on the dissipation of chlorantraniliprole and fludioxonil on Dendrobium officinale Kimura et Migo.And the influence of soil type,temperature and oxygen condition on the degradation of the pesticide within the door environment were examined.What's more,through the soil column eluviation experiment in laboratory,the eluviation law of chlorantraniliprole and fludioxonil in different soils were studied.The results were summarized as follows:(1)Methods were developed for the determination of chlorantraniliprole and fludioxonil in Dendrobium officinale Kimura et Migo.Samples were extracted with ethyl acetate,cleaned up by neutral Al2O3 SPE column,and determined by high performance liquid chromatography with UV detector(HPLC-UV).The limit of quantification(LOQ)of chlorantraniliprole in fresh leaf,fresh stem,dry stem and matrix was 0.02 mg/kg,0.01 mg/kg,0.02 mg/kg,and 0.02 mg/kg,respectively.The LOQ of fludioxonil in fresh leaf,fresh stem,dry stem and matrix was 0.02 mg/kg,0.01 mg/kg,0.02 mg/kg,and 0.02 mg/kg,respectively.(2)Dissipation of chlorantraniliprole and fludioxonil on Dendrobium officinale Kimura et Migo were fitted to the first-order kinetic equation.The half-lives of chlorantraniliprole in Dendrobium officinale Kimura et Migo were 22.90 d(fresh leaf),26.47 d(fresh stem),and 26.39 d(matrix),respectively:the residue of chlorantraniliprole was 0.33-0.61 mg/kg in fresh stem and 1.68-3.35 mg/kg in dry stem after 84 days of it's application.The half-lives of fludioxonil in Dendrobium officinale Kimura et Migo were 16.82 d(fresh leaf),21.66 d(fresh stem),and 15.07 d(matrix),respectively;the residue of fludioxonil was 0.25-0.70 mg/kg in fresh stem and 1.16-2.06 mg/kg in dry stem after 84 days of it's application.Because of the chemistry's stability,perennial plant and greenhouse planting,chlorantraniliprole and fludioxonil on Dendrobium officinale Kimura et Migo had longer half-lives and higher residue.(3)In indoor environment,the degradation of chlorantraniliprole and fludioxonil in soil under different conditions,such soil type,temperature,and oxygen condition,were all fitted to the first-order model.In different soil condition,the half-lives of chlorantraniliprole were 135.91 d(Hangzhou),169.06 d(Xi'an),187.33 d(Baoding),and 177.33 d(Ha'erbing),respectively;the half-lives of fludioxonil were 72.96 d(Hangzhou),133.30 d(Xi'an),91.20 d(Baoding),and 126.03 d(Ha'erbing),respectively.Under different temperature condition,the half-lives of chlorantraniliprole were 266.60 d(15?),135.91 d(25 ?),and 54.15 d(35 ?),respectively;the half-lives of fludioxonil were 86.64 d(15 ?),72.96 d(25 ?),and 65.39 d(35 ?),respectively.Under different oxygen condition,the half-lives of chlorantraniliprole were 78.76 d(anaerobic condition)and 135.91 d(aerobic condition);the half-lives of fludioxonil were 82.52 d(anaerobic condition)and 72.96 d(aerobic condition).The causes of half-lives difference were microbial condition,organic matter content,pH,soil granule composition,cation exchange capacity,etc.(4)Through the study on the eluviation law in different soils,chlorantraniliprole and fludioxonil had less migration in uprightness direction.Most of their residual were in soil between 0-10 cm.They all had the weak leaching ability because of their low water solubility and soil adsorption.