5种高效低毒化学农药在苜蓿中的残留动态分析

Analysis of Residues and Degradation Dynamics of Five Pesticides in Medicago sativa

[目的]明确各药剂在苜蓿上的半衰期,为宁夏苜蓿产业的农药安全使用提供理论依据。[方法]5种药剂按照推荐剂量1次施药和推荐剂量2次施药,采用Excel进行残留量指数拟合,通过残留消解动态方程式计算半衰期。[结果]1.8%阿维菌素乳油和5%啶虫脒可湿性粉剂在苜蓿中消解速度较快,1次和2次施药14 d后均未检出,70%吡虫啉水分散粒剂21 d未检出,4.5%高效氯氰菊酯乳油和21%毒死蜱乳油消解速度慢,至药后28 d收获时仍可检出。[结论]距收获期较长时,防治苜蓿主要害虫可采用21%毒死蜱乳油和4.5%高效氯氰菊酯乳油;距收获期较近时可采用1.8%阿维菌素乳油、70%吡虫啉水分散粒剂、5%啶虫脒可湿性粉剂或提前刈割等措施。

[Aims] The half-life of each pesticide was determined, which provide the basis for safe use of pesticides on Medicago sativa. [Methods] Five pesticides were used in accordance with the recommended dose for one time and two times, respectively. Residual index was fitted with excel. The half-life of each pesticide was calculated using equation of residues and degradation dynamics. [Results] The degradation speed of avermectins 1.8% EC and acetamiprid 5% WP were quick and the residues could not be detected after 14 d of one and two times application. The residues of imidacloprid 70% WG could not be detected after 21 d of one and two times application. The degradation speed of beta-cypermethrin 4.5% EC and chlorpyrifos 21% EC were slow and the residues could be detected after 28 d of one and two times application. [Conclusions] When it is longer time from the harvest, control of main pests on M. sativa Linn is suggested to use chlorpyrifos 21% EC and beta-cypermethrin 4.5% EC. When it is close to harvest, control of main pests on M. sativa Linn is suggested to use avermectins 1.8% EC, imidacloprid 70% WG and acetamiprid 5% WP, or cut in advance.