Residual Digestion Of Fludioxonil In Tomato And Its Effects On Physiological And Biochemical Properties And Edible Qualities Of Tomato

Fludioxonil is a new non-systemic phenylpyrrole fungicide developed by Syngenta Crop Protection Co.,Ltd.,which is used to control soil-borne diseases caused by pathogens such as Ascomycetes and Sclerotinia sclerotiorum.Late blight,gray mold and so on.In particular,it has a significant control effect on gray mold caused by Botrytis cinerea.At present,there are few reports on the residual digestion dynamics of fludioxonil in tomato and soil,and its impact on crops.In this paper,after spraying 50%fludioxonil wettable powder on tomato and soil in greenhouse and field,the residual digestion behavior of fludioxonil was investigated,and whether the physiological and biochemical characteristics and edible quality of tomato were produced after spraying fludioxonil.The impact provides some basic data for the formulation of the amount of sputum nitrile in tomato,the number of applications,the safe range and the application of the guidelines.In this paper,an analytical method for the determination of fludioxonil in tomato and soil in greenhouses and fields was established.Acetyl nitrile in tomato fruit and soil was extracted with acetonitrile aqueous solution,purified by PSA purifying agent and silica-magnesium adsorbent,and then analyzed by C₁₈8 reversed-phase column,mobile phase was acetonitrile-formic acid aqueous solution,ultra-high performance liquid chromatography Tandem mass spectrometry?UPLC–MS/MS?multiple reaction monitoring,electrospray is a negative ion source mode,and the quantitative method is external standard method.The detection limits of fludioxonil in tomato fruits and soil were all 0.4?g·kg^-1,and the limit of quantification was 1.4?g·kg^-11 and 1.3?g·kg^-1,respectively.The average recovery was 95.96%¹03.17%and 88.21%¹06.88%,relative standard deviation?RSD?were 1.8%⁴.6%and 1.1%⁶.2%,respectively.The analysis time,sensitivity,accuracy and precision of the UPLC–MS/MS method meet the requirements of pesticide residue analysis.In 2017,in the greenhouse in Heilongjiang Province and in 2018 in the field of Heilongjiang Province,the residual digestion study of fludioxonil was carried out,including dynamic test and final residue test.The final residue test for fludioxonil was divided into two groups,the low dose group and the high dose group,according to the safely recommended dosage.The effective dose of fludioxonil in the low-dose group was 108 g·ha^-1,and the effective dose in the high-dose group was 216 g·ha^-1.In the low-dose and high-dose groups,two or three administration groups were set up,and the application interval was 7 days.The residual amount of fludioxonil in tomato fruit and soil after harvesting was determined 3,5,and 7 days after the last application interval.The results showed that the residual digestion behavior of fludioxonil in tomato fruit and soil accorded with the first-order reaction kinetics model.The half-life of the residual digestion of fludioxonil in the tomato fruit of greenhouse was 40.8 d.The half-life of the resolving of fludioxonil in the tomato fruit of field was 9.2 d,the half-life in the greenhouse soil was 123.8 d,and the half-life in the field soil was 11.4 d.On the 7th day after the last application,the maximum residual amount of fludioxonil in tomato fruits in greenhouse and field was 0.032 mg·kg^-11 and 0.085 mg·kg^-1,respectively.The maximum residue was 0.116 mg·kg^-11 and 0.129 mg·kg^-1.When the tomato fruit in the greenhouse in 2017 and the field in 2018 grew to half the size of the mature individual,a 50%fludioxonil wettable powder of 108 g·ha^-1 was sprayed once,respectively,after application.Tomato samples were picked at 2/24,1,2,3,5,7,10,14,21,28,and 45 d to investigate the physiological and biochemical activities?SOD activity,POD activity?of the fruit of the greenhouse and the tomato in the field.,CAT activity)and the effect of malondialdehyde content,and simultaneously determine the water,reducing sugar,organic acids,vitamin C and lycopene in greenhouse tomatoes and field tomatoes.The results showed that the SOD activity,POD activity,CAT activity and MDA content of greenhouse tomato and field tomato all showed different degrees of increase,in response to the treatment of tomato fruit by pesticide,the activity ratio of the application group compared with the control group.The control group increased significantly.The difference in bio-enzyme activity between greenhouse tomato and field tomato was not significant.The edible quality indicators of greenhouse tomato and field tomato were not significantly affected by the growth environment,dosage and sampling interval.