5种杀虫剂对滇东白背飞虱种群的毒性及其田间药效

【目的】为持续有效防控白背飞虱,研究云南东部白背飞虱种群对常用5种杀虫剂的敏感性及药剂的田间防治效果。【方法】采用室内稻茎浸渍法测定白背飞虱种群对5种杀虫剂的敏感性,同期通过田间小区试验评价5种杀虫剂对白背飞虱种群的防治效果。【结果】与敏感种群比较,噻虫嗪、噻嗪酮、吡虫啉、吡蚜酮和毒死蜱对滇东白背飞虱种群的LC_(50)分别为0.208、0.459、0.608、3.108、1.256 mg·L~(-1),抗性倍数分别为2.2、10.4、5.6、6.5、5.3倍;白背飞虱对噻虫嗪无抗性,对吡虫啉、吡蚜酮和毒死蜱为低水平抗性,对噻嗪酮为中等水平抗性;5种杀虫剂药后1、5和10 d对白背飞虱种群的田间防控效果均有显著差异。除了吡蚜酮外,其他药剂的防效均在80%以上,其中以吡虫啉和噻嗪酮的持续期较长,药后10 d仍在90%以上;噻虫嗪和吡虫啉药后1和5 d的防效达90%以上;吡蚜酮药效在供试药剂中防效最低,在64.88%～77.82%之间。【结论】滇东师宗白背飞虱种群对噻嗪酮为中等水平抗性,对吡虫啉、吡蚜酮和毒死蜱均为低水平抗性,对噻虫嗪无抗性,田间防控效果以吡虫啉和噻嗪酮为最好。建议滇东稻区可以使用吡虫啉和噻嗪酮药剂防控白背飞虱,注意控制吡蚜酮的使用次数与用量。

The population sensitivity of white-back planthopper in eastern Yunnan to five insecticides and the field control effects

Aim]We examined the control effectiveness of commonly used insecticides in a paddy field to the white-backed planthopper in eastern Yunnan.Method] Toxicity of the insecticides was assessed by using indoor straw impregnation method and experiments in field plots.Result] The LC₅₀ values of the populations to thiamethoxam, buprofezin, imidacloprid, pymetrozine and chlorpyrifos were 0.208, 0.459, 0.608, 3.108 and 1.256 mg·L^-1, and the resistance ratios were 2.2, 10.4, 5.6, 6.5 and 5.3 times, respectively. The population in eastern Yunnan was not resistant to thiamethoxam, had low resistance to imidacloprid, pymetrozine, and chlorpyrifos, and moderate resistance to buprofezin. The field control effects of insecticides on the white backed planthopper populations significantly differed after 1, 5 and 10 d of insecticide application. The effects of other insecticides were more than 80% except for pymetrozine, and imidacloprid and buprofezin were control longer duration which more than 90% at 10 d, and thiamethoxam and imidacloprid were over 90% after spraying at 1 d and 5 d. Pymetrozine was the least efficient at 64.88%~77.82%.Conclusion] The population of the white-backed planthopper from Shizong county was moderately resistant to buprofezin, and had low level of resistance to imidacloprid, pymetrozine and chlorpyrifos, not resistant to thiamethoxam. In the field, imidacloprid and buprofezin were mostly effective. Midacloprid nd buprofezin were recommended to control the white-backed planthoppers in rice growing area of eastern Yunnan, and to limit the usage times and dosage of pymetrozine.