Study On The Residue And Metabolism Of Imidacloprid On Tomato

Imidacloprid is a kind of neonicotinoid insecticide widely used,with low toxicity and high efficiency.It is mainly used to control the biting and sucking mouthparts pests on various crops,such as aphids,aphids,planthoppers,mealworms,leafhoppers,thrips and so on.However,excessive use of this pesticide will pose a threat to the environment and human body.Therefore,it is very important to study the residue,distribution and transformation of imidacloprid on crops to reduce the use of imidacloprid.In this paper,tomatoes with more imidacloprid application were selected as subjects to study the residual characteristics and metabolism of imidacloprid on tomatoes.The results are as follows:1.Imidacloprid in the recommended dose(tomato:4 g-6 g)of low dose of 0.5,0.75,1,1.5 times on tomato,applying pesticide by comparing system of tomato planting in various parts of the original deposit amount,the results show that the four kinds of pesticide concentrations,with the increase of applying pesticide concentration,tomato leaf,middle,lower lobe on the amount of imidacloprid primary sedimentary are on the rise trend,imidacloprid in planting soil original deposit amount no change.In each application concentration,imidacloprid residues generally showed the trend of>in the upper leaf of tomato>in the middle leaf of tomato>in the lower leaf of tomato.2.The spatial distribution characteristics of imidacloprin in three growth stages(seedling stage,flowering stage and fruiting stage)were studied at the concentration of 1.5 times of the recommended low dose.The spatial distribution of imidacloprid in the whole tomato planting system was analyzed by detecting the residues of imidacloprid in different parts of the tomato planting system.The results showed that:seedling stage:leaf>planted soil;Flowering stage:upper leaf>middle leaf>lower leaf>planting soil;Fruit stage:upper leaf>middle leaf>lower leaf>planting soil>fruit.The spatial distribution pattern of imidacloprid in tomato planting system in three growth periods was consistent.3.Comparing the degradation of imidacloprid in different environments,the results showed that the degradation rate of imidacloprid in the upper leaf and fruit of tomato was faster in the open field than in the shed,and the degradation rate of imidacloprid in the middle leaf,lower leaf and planting soil of tomato was faster in the shed than in the open field.4.The dynamic digestion test results of imidacloprid on different parts of tomato planting system showed that the half-life of imidacloprid on tomato leaves was 0.41～4.39 days.The half-life of imidacloprid on tomato fruits was 4.22～5.33 days.The half-life of imidacloprid in the cultivated soil was 7.22～10.19 days.5.The metabolites of imidacloprid on tomato were detected by liquid chromato graphy tandem mass spectrometry(UPLC-MS/MS)and high performance liquid chromatography(HPLC).Imidacloprid contained imidacloprid and imidacloprid olefin in tomato leaves and fruits,and the content of imidacloprid was higher than that of imidacloprid olefin.