不同杀虫剂对荞麦害虫西伯利亚龟象的毒力及作用机制研究

Toxicity and mechanism of insecticides to Rhinoncus sibiricus Faust in buckwheat

荞麦Fagopyrum esculentum Moench.是我国重要的杂粮作物,内蒙古是我国甜荞的主产区,西伯利亚龟象Rhinoncus sibiricus Faust是2013年在内蒙古地区新发生的严重为害荞麦的害虫,目前主要依靠化学杀虫剂进行防治。本论文主要研究了不同种类杀虫剂对西伯利亚龟象的毒力和作用机制。结果显示,拟除虫菊酯类杀虫剂对西伯利亚龟象的毒力大于有机磷、氨基甲酸酯类和烟碱类杀虫剂,其中菊酯类杀虫剂中高效氯氰菊酯毒力最大,致死中浓度LC_(50)为17.37 mg/L;氨基甲酸酯类杀虫剂中丁硫克百威毒力最大,LC_(50)为29.56 mg/L;有机磷杀虫剂中毒力最大的是三唑磷,LC_(50)为32.05 mg/L;烟碱类药剂噻虫嗪和吡虫啉对荞麦害虫西伯利亚龟象的LC_(50)分别为42.14 mg/L和46.19 mg/L。供试的氨基甲酸酯类杀虫剂对西伯利亚龟象AChE的抑制作用大于有机磷杀虫剂,灭多威对西伯利亚龟象AChE抑制作用最强,IC_(50)为6.33×10^(-5) mol/L,丁硫克百威次之;三唑磷对对西伯利亚龟象AChE的抑制作用大于其它两个有机磷杀虫剂,IC_(50)为53.46×10^(-5) mol/L。丁硫克百威对AChE抑制中时间最短,IT_(50)为4.07 min,乐果和三唑磷次之,灭多威抑制中时间最长,IT_(50)为6.57 min。5种菊酯类杀虫剂对西伯利亚龟象K{3 Na^(+)-K^(+)-ATPase和Ca^(2+)-Mg^(2+)-ATPase都有抑制作用,对Na^(+)-K^(+)-ATPase的抑制程度高于对Ca^(2+)-Mg^(2+)-ATPase的抑制,溴氰菊酯的抑制作用最强,高效氯氰菊酯的抑制作用相对最弱。因此,生产中推荐以菊酯类杀虫剂和有机磷、氨基甲酸酯类杀虫剂交替轮换使用防治西伯利亚龟象。

Fagopyrum esculentum Moench.is an important grain crop,and distributes mainly in Inner Mongolia in China.Rhinoncus sibiricus Faust is a serious pest of F.esculentum and recorded in Inner Mongolia in 2013.R.sibiricus is controlled by chemical insecticides respectively at present.The toxicity and mechanism of different insecticides on R.sibiricus were studied in this paper.The results showed that the toxicity of pyrethroid insecticides to R.sibiricus was greater than that of organophosphorus,carbamate and nicotine insecticides.Among tested pyrethroids,R.sibiricus was the most sensitive to beta-cypermethrin,with LC_(50) of 17.37 mg/L.R.sibiricus was the most sensitive to carbosulfan and triazophos among tested carbamate and organophosphorus insecticides,with LC_(50) of 29.56 mg/L and 32.05 mg/L respectively.LC_(50) of thiamethoxam and imidacloprid to R.sibiricus was 42.14 mg/L and 46.19 mg/L respectively.The inhibition of carbamate insecticides on AChE of R.sibiricus was greater than that of organophosphorus insecticides.Median inhibitory concentration(IC_(50))of methomyl on AChE was 6.33×10^(-5) mol/L,it was higher than that of carbosulfan.Inhibition of triazophos was the strongest among organophosphorus insecticides,and IC_(50) was 53.46×10^(-5) mol/L.Median inhibitory time(IT_(50))of carbosulfan to AChE was the shortest,IT_(50) was 4.07 min,followed by dimethoate and triazophos.IT_(50) of methomyl was the longest of 6.57 min.The activity of Na^(+)-K^(+)-ATPase and Ca^(2+)-Mg^(2+)-ATPase of R.sibiricus were inhibited by five pyrethroid insecticides.Inhibition on Na^(+)-K^(+)-ATPase was higher than that of Ca^(2+)-Mg^(2+)-ATPase.Inhibitions of deltamethrin to two kinds of ATPase were the strongest,while inhibitions of cypermethrin to them were the weakest.Pyrethroids and organophosphorus,carbamate insecticides should be used alternately in order to control R.sibiricus effectively.