水稻上吡蚜酮残留的空间差异及对灰飞虱防治效果的影响

为研究吡蚜酮在水稻空间立体和不同种植区域间残留的差异以及对灰飞虱防治效果的影响,在全国不同农区布置试验点,采用液相色谱三重串联四极杆质谱联用仪检测吡蚜酮的残留量,分析吡蚜酮的残留特性。结果显示,在药后2 h,江苏、湖南、广西和黑龙江4地水稻植株上部沉积量所占比例均为整个植株沉积量的66.7%以上。水稻植株上部吡蚜酮沉积量,黑龙江大于其余3地。吡蚜酮在江苏、湖南、广西和黑龙江4个试验点水稻植株上部的半衰期分别为2.1、1.0、2.1 d和2.4 d,但在植株下部的半衰期分别为2.8、1.7、3.2 d和3.6 d。吡蚜酮在水稻植株上部的降解要快于植株下部。吡蚜酮在水稻上的沉积量与防治效果的研究表明,江苏和湖南地区水稻飞虱防治用吡蚜酮药按标签推荐最大的75%用药即可满足防治需求(56 g·hm-2,以有效成分计)。广西双季稻地区水稻飞虱防治用吡蚜酮药剂时,其用量应为标签推荐的1.5倍用量(112.5 g·hm-2,以有效成分计)。黑龙江一季稻地区水稻飞虱防治用吡蚜酮药剂时,其用量应为标签推荐的1.0倍用量(75 g·hm-2,以有效成分计)。试验表明,针对具体农药制剂,应根据实际水稻种植区域靶标有害生物防治效果,合理设置符合本区域的农药施用剂量,避免农药使用过量给环境造成压力,也避免农药使用不足而起不到应有的防治害虫的效果。

Effects of spatial differences of pymetrozine on control efficacy of Laodelphax striatellus in rice

In order to study the Effects of spatial differences of pymetrozine on control efficacy of Laodelphax striatellus in rice, the residues of pymetrozine in different agricultural areas of China were detected by liquid chromatography tandem triple quadrupole mass spectrometry (LC-MS/MS), and the characteristics of the pymetrozine residues were analyzed. The results showed that 2 h after treatment, the upper part of rice in Jiangsu, Hunan, Guangxi, and Heilongjiang accounted for more than 66.7% of the whole plant deposition. The pymetrozine deposition in the upper part of the rice plant in Heilongjiang Province was higher than in the other three regions. The half-life of pymetrozine in the upper part of rice plants in Jiangsu, Hunan, Guangxi, and Heilongjiang was 2.1, 1.0, 2.1, and 2.4 days, respectively, while that in the lower part was 2.8, 1.7, 3.2, and 3.6 days, respectively. The degradation of pymetrozine in the upper part of the rice plant was faster than that in the lower part of the plant. The results showed that 75% the recommended maximum amount of pymetrozine on rice (56 g·hm^-2, based on the active ingredients) could effect control in Jiangsu and Hunan Provinces. The dosage of pymetrozine should be 1.5 times the recommended dosage(112.5 g·hm^-2, based on active ingredients) in the Guangxi double-cropping rice area. The dosage of pymetrozine should be 100% the recommended dosage(75 g·hm^-2, based on active ingredients) in Heilongjiang Province. The appropriate pesticide dosage should be set according to the target pest control in the rice planting area, so as to avoid the effect of the excessive use of pesticides on the environment, and the insufficient use of pesticides in the control of pests.