4种农药在梨中的残留及消解动态

Residues and Dissipation Dynamics of 4 Pesticides in Pear

[目的]为确保4种农药在不同品种梨上的安全使用,评价其在梨上的消解趋势、残留水平,并且在2018年试验的基础上,验证毒死蜱、吡虫啉的安全使用评价标准及制定高效氯氟氰菊酯、多菌灵的安全使用评价标准。[方法]参考农药标签和梨果生产中调研的施药方法,选取全国6地的黄冠梨、莱阳梨、砂梨、早酥梨、砀山酥梨和鸭梨6个梨品种,开展田间试验。利用仪器分析方法,研究了毒死蜱、高效氯氟氰菊酯、吡虫啉、多菌灵在梨中的残留消解动态。[结果]4种农药在梨中的消解动态均满足一级反应动力学方程,半衰期分别为4.2、7.1、12.2、11.9 d。毒死蜱、吡虫啉的残留量及消解动态与2018年相比,较为吻合,年度差异不大,无超标现象。高效氯氟氰菊酯、多菌灵均有超标现象,多菌灵尤为突出。[结论]必须严格控制施药剂量及施药次数,并严格遵守安全间隔期。建议按照低剂量施药,每个作物周期最多施药3次,安全间隔期为21(高效氯氟氰菊酯)、28 d(多菌灵)。按照推荐剂量及其操作规范在梨上施用是安全的。

[Aims] This study aims to ensure the safe use of 4 pesticides on different pears varieties, and evaluate the digestion trend and residue level of pear. The evaluation criteria for the safety use of chlorpyrifos and imidacloprid were verified on the basis of the 2018 experiment, and further to formulate safety use evaluation standards for lambda-cyhalothrin and carbendazim. [Methods] Six pear varieties(Crown pear, Laiyang pear, Sand pear, Zaosu pear,Dangshan pear and Yali pear) from 6 places in China were selected to carry out field experiment by referring to pesticide label and application method of pear production research. The instrument analysis method were employed for the investigation of the dissipation dynamics and residues of chlorpyrifos, lambda-cyhalothrin, imidacloprid and carbendazim, in pear. [Results] The results showed that the dissipation dynamics of 4 pesticides, in pear meet the first-degree dynamics matrix. There half-lives were 4.2, 7.1, 12.2 and 11.9 d, respectively. Compared with that of 2018,the residue and digestion dynamics of chlorpyrifos imidacloprid were in good agreement, and the annual difference was not significant. The l ambda-cyhalothrin and carbendazine all exceeded the standard, especially carbendazine.[Conclusions] Dosage and frequency of application must be strictly controlled, and safety intervals must be strictly observed. It is recommended to apply at a low dose, up to 3 times per crop cycle, with a safe interval of 21(lambda-cyhalothrin) and 28 days(carbendazine). It is safe to apply the pear in accordance with the recommended dosage and operating instructions. All four pesticides can be safely used on pears.