马铃薯及土壤中烯酰吗啉的残留及消解动态研究

烯酰吗啉(dimethomorph,DMM)是一种新型内吸治疗性专用低毒杀菌剂,广泛用于晚疫病等病害的防治。为合理将烯酰吗啉用于马铃薯晚疫病防治,采用液相色谱-质谱联用(UPLC-MS)方法研究不同年份(2015、2016年)不同产地(宁夏回族自治区、黑龙江省)烯酰吗啉在马铃薯块茎、植株和土壤中的消解动态及最终残留量。结果表明:2015年和2016年烯酰吗啉在马铃薯植株中的半衰期分别为22.36 d(宁夏)、12.38 d(黑龙江)和3.69 d(宁夏)、28.88 d(黑龙江);在马铃薯土壤中的半衰期分别为231.05 d(宁夏)、6.48 d(黑龙江)和69.31 d(宁夏)、13.33 d(黑龙江)。烯酰吗啉施药剂量、次数和时间间隔不同,则其在马铃薯植株、块茎及土壤中的最终残留量也不同。施药量为1 345.5～2 018.2 g(a.i)/hm2,施药3～4次,施药间隔7 d,施药后14 d采收,收获马铃薯块茎中烯酰吗啉的残留量即均小于0.02 mg/kg,低于我国制定的马铃薯中烯酰吗啉最大残留限量值0.05 mg/kg。

Study on Residue and Degradation Dynamics of Dimethomorph in Potato and Its Soil

Dimethomorph is a new kind of therapeutic special fungicide, widely used in disease prevention and control of late blight. In order to reasonably apply dimethomorph in the prevention and treatment of potato late blight, this experiment used the method of UPLC-MS to study the dissolution dynamics and final residues of dimethomorph in potato tubers, plants and soil from different places (Ningxia Hui Autonomous Region and Heilongjiang Province) in different years (2015 and 2016). The results showed that the half-lives of dimethomorph in potato plants were 22.36 d (Ningxia) and 12.38 d (Heilongjiang) in 2015, 3.69 d (Ningxia) and 28.88 d (Heilongjiang) in 2016. The half-lives of dimethomorph in soil were 231.05 d (Ningxia) and 6.48 d (Heilongjiang) in 2015, 69.31 d (Ningxia) and 13.33 d (Heilongjiang) in 2016. The final residues of dimethomorph in potato plants, tubers and soil were different with different dosages, times and time intervals. When the dosage was 1 345.5~2 018.2 g (a.i)/hm2, the spraying times was 3~4, the interval of application was 7 days, and the residue of enylmorpholine in potato tubers was all less than 0.02 mg/kg, which was lower than the maximum residue limit of 0.05 mg/kg set in China.