Safety Evaluation Of Three Pesticides Controlling Rosa Roxburghii Tratt Pests

Rosa roxburghii Tratt is a medicinal and edible plant with Guizhou regional characteristics.It has the reputation of"vitamin C king"due to its rich vitamin C content.The occurrence of powdery mildew,Grapholitha molitor and weeds has seriously affected the yield and quality of R·roxburghii.The use of pesticides has effectively promoted the improvement of R·roxburghii yield.However,the unreasonable use of pesticides not only pollute the fruit of R·roxburghii,but also harm the ecological environment and human health.In order to provide the basis for the safe and rational use of pyraclostrobin,chlorantraniliprole and diuron in R·roxburghii production,this paper evaluated the safety of pyraclostrobin,chlorantraniliprole and diuron,which are used to control powdery mildew,fruit borer and weeds of R·roxburghii.The main results are as follows1.A rapid method for the determination of pyraclostrobin,chlorantraniliprole and diuron residues in R·roxburghii fruit and soil by liquid chromatography-tandem triple quadrupole mass spectrometry（LC-MS/MS）was established.Diuron,pyraclostrobin and chlorantraniliprole in R·roxburghii fruit samples were extracted by dichloromethane,1%ammonia-acetonitrile（V/V）,acetonitrile as well as purified by florisil,PSA and PSA respectively.While diuron,pyraclostrobin and chlorantraniliprole in soil samples were extracted by 0.1%formic acid-acetonitrile（V/V）,acetonitrile,acetonitrile as well as purified by PSA,PSA,C₁₈+PSA,respectively.The residues in fruit and soil samples were detected by LC-MS/MS Measurement.The linear range of diuron,pyraclostrobin and chlorantraniliprole was0.001～10 mg/L,the recoveries of diuron,pyraclostrobin and chlorantraniliprole in R·roxburghii and soil were 80%～110%,and the relative standard deviation（RSD）was0.64%～8.32%.The detection limits of pyraclostrobin and chlorantraniliprole in R·roxburghii fruit and soil were 0.0001 and 0.0005 mg/kg,respectively.The detection limits of diuron in R·roxburghii fruit and soil were 0.006 mg/kg and 0.001 mg/kg,respectively.2.The effects of different application devices and formulations on the spray deposition behavior of pyraclostrobin,chlorantraniliprole and diuron in R·roxburghii fruit or soil in R.roxburghii orchard were investigated.Under the conditions of the crown spray of R·roxburghii trees with different applicators and formulations,the residues of pyraclostrobin and chlorantraniliprole were detected in R·roxburghii fruits,but not in soil.Under the conditions of the soil spray with different applicators and formulations,the residues of diuron were detected in soil,but not in R·roxburghii fruits.The effects of different pesticide application devices and formulations on the initial deposition and half-life of three pesticides mentioned above were as follows:gasoline sprayer>manual sprayer>electric sprayer,suspension concentrate（SC）>wettable powder（WP）>water dispersible granule（WG）,SC>granules（GR）>WG.3.The degradation dynamics and final residues of 30%pyraclostrobin SC,200g/L chlorantraniliprole SC and 80%diuron WP in R·roxburghii fruit or soil were studied.The half lives of 30%pyraclostrobin SC,200 g/L chlorantraniliprole SC in R·roxburghii fruit as well as soil were 6.20 and 3.45 d,as well as 3.86 and 3.02 d,respectively.The half lives of 80%diuron WP in soil were 12.98 d.The final residues of pyraclostrobin and chlorantraniliprole in R·roxburghii fruit as well as soil were0.169～1.065 mg/kg and 0.034～0.741 mg/kg as well as 0.105～3.153 mg/kg and0.088～3.109 mg/kg,respectively.The final residues of diuron in soil were0.038～3.509 mg/kg,and the final residues of diuron in R·roxburghii fruit were lower than the detection limits.4.The dietary risk of pyraclostrobin,chlorantraniliprole and diuron in R·roxburghii fruit was evaluated and identified.The long-term risk quotient of pyraclostrobin,chlorantraniliprole and diuron in R·roxburghii fruit were 0.109、9.9×10^-4and less than 3.3×10^-3,the short-term risk quotient were 0.197、2.1×10^-3and less than 3.3×10^-3,all of those were lower than 1,which proves that the risk is acceptable and safe to eat.