新烟碱类药剂不同施药方式对油菜蚜虫的防控效果及其安全性

为了明确吡虫啉和噻虫嗪2种新烟碱类药剂在播种期施药对油菜整个生长期蚜虫的防控效果及其在油菜不同发育阶段中的农药残留量和增产效果,采用播种沟撒施和播种后覆土然后撒施于土表2种施药方法进行研究。结果表明,油菜播种沟撒施70%吡虫啉种子处理可分散粉剂420~600 g/hm2和70%噻虫嗪种子处理可分散粉剂420 g/hm2及覆土后土表撒施70%噻虫嗪种子处理可分散粉剂420 g/hm2对油菜整个生长期蚜虫危害均有较好的防控效果,其中对油菜苗期蚜虫始盛期至减退期的防治效果达98.98%~100.00%,对油菜返青至花期蚜虫的防治效果达79.61%~98.51%,最终使油菜产量增加17.47%~27.19%,且播种沟撒施70%吡虫啉种子处理可分散粉剂420 g/hm2处理油菜籽粒中农药残留低于美国规定的吡虫啉最高残留限量(0.05 mg/kg)。综合分析,播种期播种沟撒施70%吡虫啉种子处理可分散粉剂420 g/hm2和70%噻虫嗪种子处理可分散粉剂420 g/hm2及覆土后土表撒施70%噻虫嗪种子处理可分散粉剂420 g/hm2不仅对油菜安全,可高效防控油菜蚜虫危害,增产效果显著,而且产品中农药残留在安全标准范围内。

Control Effects of Different Application Methods of Imidacloprid and Thiamethoxam against Rape Aphids and Their Safety to Rape

The control effects of 70% imidacloprid WS( active ingredient 420 g/ha,600 g/ha) and 70%thiamethoxam WS( active ingredient 420 g/ha) applied in sowing time on rape aphids during the whole growing seasons,the residues of imidacloprid and thiamethoxam in rape in different growing stages, and the yield of rapeseed were investigated for evaluating the control effects of these two insecticides. The re-sults showed that by spreading 70% imidacloprid WS 420—600 g/ha and 70% thiamethoxam WS 420 g/ha in the sowing ditch and by spreading 70% thiamethoxam WS 420 g/ha on the topsoil after covered,they all had good control effects against rape aphids,with 98. 98%—100. 00% from prosperous beginning pe-riod to decline period of rape aphids in seedling stage,and 79. 61%—98. 51% from returning green stage to flowering stage,and had good yield-increasing rate with 17. 47%—27. 19%. The residue in rapeseed of imidacloprid by spreading 420 g/ha in the sowing ditch was lower than the highest limited standard in USA(0. 05 mg/ kg). The treatments spreading 70% imidacloprid WS 420 g/ ha or 70% thiamethoxam WS 420 g/ ha in the sowing ditch and 70% thiamethoxam WS 420 g/ ha on the topsoil after covered were safe to rape, had good control efficacy on rape aphids and significant yield-increasing rate,and remained lower residues in products.