Residues And Dissipation Dynamic Of Spinosad And Emamectin Benzoate In Cowpea

Emamectin Benzoate,compounded by fermentation products of Abamectin B1,is a new type of efficient semi-synthetic antibiotic insecticides.Its insecticidal mechanism mainly is to enhance a nervous,such as glutamic acid and gamma aminobutyric acid(GABA),So that a large number of gamma-aminobutyric acid into nerve cells,Disrupt the nerve conduction,make the cell function loss.When larvae touch it immediately to stop eating,irreversible paralysis occurs.To achieve the highest fatality rate in 3-4 days,The lepidoptera insect larvae,and many other high activity of insect pests and mites.Spinosad is a large ring lactone class pollution-free and efficient biological pesticides.The mechanism of action of it is by stimulating the nervous system of insects,to increase its spontaneous activity.Lead to non-functional muscle contraction and trembling and paralysis.Show type nicotinic acetylcholine receptors(n C h R)caused by continuous activation acetylcholine(Ach)extended release reaction.Pest control effect of lepidoptera,diptera and thysanoptera is obvious.In order to understand 10% Spinosad SC and 3% Emamectin Benzoate microemulsion use and the environment in the citrus residue,to evaluate the safety,for the rational use of pesticides,supervision of agricultural production to ensure quality and safety and environmental safety of agricultural products to provide evidence.This article 10% Spinosad SC and 3% Emamectin Benzoate microemulsion and environment in the citrus residue analysis methods and degradation dynamics were studied.The main results were as follows:Firstly,a residue detection method of Emamectin Benzoate by LC-MS/MS method was established.The method shows a good linearity within a range of 1~200 ? g/L,y = 2208.81 x + 1873.94,r=0.9999.The recoveries for cowpea was from 80.74%~91.62%.The relative standard deviation(RSD)for the samples was from 2.89%~5.35%.a residue detection method of Spinosad by LC-MS/MS method was established.The method shows a good linearity within a range of 1~200?g/L,y=2413.79x+1346.89,r=0.9999.The recoveries for cowpea was from 84.12%~95.82%.The relative standard deviation(RSD)for the samples was from 2.96%~3.91%.Secondly,the dynamic of residue degradation of 10% Spinosad SC·3% Emamectin Benzoate microemulsion in cowpea was studied by field plot test.After spraying in cowpea one time at 2 times of the recommended dosage 7.2 g/ha and 45 g/ha,the experimental results of residual degradation showed that the degradation process of emamectin benzoate and spinosad in cowpea was in accordance with the first order kinetics model.And there are exist a certain difference due to the different test environment.The half-life of emamectin benzoate in cowpea in 2016 was 2.46 d in Hainan,2.78 d in Shandong.The half-life of spinosad in cowpea was not detected.Finally,the experimental results of the final residues showed that: using 10% Spinosad SC·3% Emamectin Benzoate microemulsion to control the bean-pod borer in cowpea,whether the recommended dosage and 2 times of the recommended dosage was sprayed the final amount of emamectin benzoate and spinosad in cowpea was all less than the maximum residue limits(MRL)after 3 days from the last application,the dosage is considered to be safe for cowpea.Author proposed that the safety interval should be 7 days and harvest was determined for safe use of the pesticide.The maximum dosage should 3.6 g/ ha and 45 g/ha,and the spray time should not be more than 2 times.