Research On The Effect Of Pesticide Adjuvants On The Deposition Of Typical Pesticides On Citrus

How to improve the effective utilization rate of pesticides has become a research hotspot in the field of agrochemicals.In this study,the effects of mineral oil,silicone and FMES pesticide additives were investigated on the deposition of typical pesticides,the effects of digestion rate and half-life on citrus.The commonly used pesticides acetamiprid,pyridaben bifenthrin and difenoconazole,were used to study the deposition effect,spatial distribution characteristics and degradation rate on citrus samples after the same spraying method.To analyze the key factors affecting the target deposition and effective utilization of pesticides,so as to provide a basis for the efficient,safe and scientific use of pesticides.The main research contents are as follows:1.The acetamiprid was determined by LC-MS/MS in the citrus（pulp,whole citrus,soil）.Acetonitrile and ethyl acetate were used as the main extractant,and extracted by ultrasonic vortex,and purified by PSA and detected by LC-MS/MS.The results showed that the average recovery rate of acetamiprid was 73.4-104.3%,and the inter-day relative standard deviation（RSD）（n=15）was 2.7-8.4%in citrus（pulp,whole citrus,soil）.n the pyridaben,bifenthrin and difenoconazole were determined by GC-MS/MS in citrus（pulp,whole citrus,soil）.Acetonitrile was used as extractant,extracted by ultrasonic vortex,purified by C₁₈,and detected by GC-MS/MS.The results showed that the average recovery rate of pyridaben was 70.4-103.4%,the inter-day RSD（n=15）was 1.3-8.4%;The average recovery rate of bifenthrin was78.9-103.5%,the inter-day RSD（n=15）was 3.0-11.0%;the average daily recovery rate of difenoconazole was 75.9-102.3%,and the inter-day RSD（n=15）was 2.5-9.2%in citrus（pulp,whole citrus,soil）.The accuracy,precision and sensitivity of this method are consistent with pesticide residue analysis requirements.2.By comparing the deposition characteristics of four pesticides on citrus samples under different additives,it was found that when pesticides were sprayed on citrus,they were mainly deposited on citrus leaves,accounting for 70-90%.Less than10-25%deposited on fruits,only a small part was lost in the soil.The main pests and diseases on citrus were mainly concentrated on the citrus leaves.Therefore,the spray of acetamiprid,paridaben,bifenthrin and difenoconazole could concentrate on the site of pests and effectively prevent pests and diseases on citrus.3.Comprehensive analysis of the deposition regularity of four pesticides under different additives.The study found that mineral oil auxiliary can increase the deposition and improve the effective utilization of chemical pesticides on citrus leaves.The average increase was-1.9-64.79%,the average value was increased to 17.09%of the effective deposition amount;FMES auxiliary could not increase the deposition of chemical pesticides on citrus;the effect of silicone auxiliaries on the deposition of chemical pesticides has uncertainty on citrus for further study.4.The acetamiprid,bifenthrin,pyridaben and difenoconazole were easily degradable pesticides,respectively,the average half-life was 2.4-8.0 d,2.3-9.7 d,1.4-7.1 d,1.5-3.9 d on citrus.The silicone,mineral oil and FMES additives had no significant effect on the half-life of the four pesticides.