Study On The Safe Medication Technology Of 6 Acaricides On Lycium Barbarum

Aceri macrodonis Keifer is one of the main pests on Lycium barbarum,also known as Acarina,belonging to Eriophyidae.It is distributed in the production areas of L.barbarum in China.In order to effectively prevent and control A.macrodonis six new acaricides were selected to carry out indoor toxicity determination and field control effect test on A.macrodonis,and the residue detection method of the new acaricide was established.At the same time,the residue detection test was carried out on two kinds of acaricides that were not studied on the residue of L.barbarum to determine the dissipation dynamics and residue half-life of the pesticide,which provided a theoretical basis for the safe interval of the pesticide in production practice.The main results are as follows:1.The toxicity and field control effects of six pesticides on L.barbarum were determined by leaf dipping method and conventional spray method,respectively.The optimal control concentration of each pesticide was determined by indoor toxicity determination and field efficacy.The results showed that the effects of six acaricides on the activity of A.macrodonis increased with the prolongation of time,and the toxicity of each agent to A.macrodonis was significantly different.Among them,43%Bifenazate suspension had a weak toxic effect on A.macrodonis,and the LC50 at 24 h and 48 h were 784.476 mg/kg and 498.900 mg/kg,respectively.The 20%Fenpropathrin EC had the best toxic effect on A.macrodonis,and the LC50 at 24 h and 48 h were 151.481 mg/kg and 101.561 mg/kg,respectively.The relative toxicity index was about 5 times higher than that of Bifenazate.The toxicity of the rest to A.macrodonis was 20%Amitraz EC,30%Cyetpyrafen SC,24%Spirodiclofen SC and 30%Fenpyroximate SC.Six kinds of acaricides also had good effect on the field control of A.macrodonis.The control effect of the test agents increased gradually with the prolongation of time.The effective components of the agents were applied twice continuously.The control effect of the high concentration of the test agents was more than 75.0%after 14 days of treatment,which was better than 20%Pyridaben wettable powder used to control A.macrodonis in production.The field control effects of the test agents were 30%Cyetpyrafen SC>20%Fenpropathrin EC>43%Bifenazate SC>20%Amitraz EC>24%Spirodiclofen diester SC>30%Cyenopyrafen SC.2.Three kinds of extraction solvents were selected to carry out the recovery test of wolfberry samples with Cyenopyrafen standard,and the best extraction solvent was selected to establish the residue detection method of Cyenopyrafen in wolfberry fruit.The experimental results showed that the recovery rates of Cyenopyrafen in wolfberry fresh fruit samples extracted by acetonitrile,ethyl acetate and methanol were 96.2-101.1%,92.5-100.4%and 89.1-100.2%,respectively.In the process of recovering dried wolfberry fruit,the drug precipitation time was long.The average recovery rate of acetonitrile was higher than that of the other two,and the recovery rate after treatment was 96.5100.8%,followed by methanol and ethyl acetate.The recovery rates of Cyenopyrafen in dried wolfberry fruit were 95.4-103.6%and 75.4-94.3%,respectively.In this paper,acetonitrile was selected as the best extraction solvent to determine the residue of Cyenopyrafen in wolfberry fruit.3.The residues of two new pesticides in wolfberry fruit were determined to determine their digestion dynamics and half-life.The results showed that there was a correlation between the residue and time in the fresh and dry fruits of Lycii Fructus treated with the recommended dose,double dose and secondary application of Cyenopyrafen and Cyetpyrafen,and the digestion dynamics were in accordance with the first-order kinetic equation.The half-life of Cyenopyrafen in fresh and dried fruits of L.barbarum was 0.99-1.29 d<30 d.The half-life of Cyetpyrafen in fresh and dried wolfberry fruit was 0.73-0.89 d<30 d.The half-life of the two pesticides on wolfberry fruit was short,and both of them were easily digested pesticides.In the production,it is recommended to use the recommended dose(200 mg a.i./kg)and double dose(400 mg a.i./kg)of 30%Cyenopyrafen to control wolfberry pests.The recommended dose should be applied once or twice,and the double dose should be applied once.The safe harvest intervals are not less than 30,32 and 35 days,respectively.When 30%Cyetpyrafen recommended dose(100 mg a.i./kg)and double dose(200 mg a.i./kg)were used to control A.macrodonis,the recommended dose was applied once or twice,and the double dose was applied once,the harvest safety interval was not less than 23 d and 25 d.