新烟碱杀虫剂环氧虫啶对苜蓿蚜的毒力及其在苜蓿蚜和水稻中的降解转化

为明确顺硝烯新烟碱杀虫剂环氧虫啶对苜蓿蚜Aphis craccivora Koch的毒力及其在苜蓿蚜体内和水稻中的降解转化趋势,采用带虫浸液法测定环氧虫啶及其降解产物NTN23692对苜蓿蚜的毒力,并采用超高效液相色谱检测法研究苜蓿蚜体内不同酶对环氧虫啶降解转化的影响以及环氧虫啶在水稻中降解转化为NTN23692的情况。结果表明:环氧虫啶及其降解产物NTN32692对苜蓿蚜的LC_(50)分别为3.45 mg/L和0.79 mg/L,NTN32692的毒力明显高于环氧虫啶。与对照组相比,在添加酶抑制剂的条件下,苜蓿蚜谷胱甘肽S-转移酶孵育液中环氧虫啶和NTN32692的浓度均显著降低,羧酸酯酶和细胞色素P450酶孵育液中环氧虫啶和NTN32692的浓度变化不显著。用不同浓度环氧虫啶处理水稻24 h后,叶片中环氧虫啶和NTN32692的累积量随着浓度提高均显著增加;在水稻中的残留动态表明,培养7 d后,叶片中环氧虫啶和NTN32692的浓度皆显著降低,降幅分别达到67.33%和89.42%。

Toxicity of the new neonicotinoid insecticide cycloxaprid on groundnut aphid Aphis craccivora and its degradation and transformation in A. craccivora and rice plants

To figure out the insecticidal activity of cycloxaprid against groundnut aphid Aphis craccivora Koch, the leaf-dip method was performed to test the acute toxicity of cycloxaprid and NTN32692 on A. craccivora, and ultraperformance liquid chromatography (UPLC) method was adopted to study the hydrolysis of cycloxaprid into NTN32692 in A. craccivora and rice plants. The LC₅₀ value of cycloxaprid against A. craccivora was 3.45 mg/L, which was lower than that of NTN32692 (0.79 mg/L). With glutathione S-transferase inhibitor treatment, the concentration of cycloxaprid and NTN32692 in A. craccivora enzymatic incubation solution was obviously less than that in the control. However, the concentrations of cycloxaprid and NTN32692 were not significantly different in A. craccivora enzymatic incubation solution with carboxylesterase inhibitor and with/without NADPH in cytochrome P450 monooxygenase. The accumulation of cycloxaprid and NTN32692 increased significantly in rice leaves with different cycloxaprid dosage treatments in 24 h. Cycloxaprid and NTN32692 were both found to be degraded in rice plants within seven days. The contents of cycloxaprid and NTN32692 in rice plants were decreased significantly, up to 67.33% and 89.42%, respectively.