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

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...

Toxicity and mechanism of insecticides to Rhinoncus sibiricus Faust in buckwheat

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 LC50 of 29.56 mg/L and 32.05 mg/L respectively . LC50 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 (IC50)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 IC50 was 53.46×10^-5 mol/L. Median inhibitory time (IT50)of carbosulfan to AChE was the shortest, IT50 was 4.07 min, followed by dimethoate and triazophos. IT50 of methomyl was the longest of 6.57 min. The activity of Na+ - K+ ATPase and Ca2+ - Mg2+ ATPase of R. sibiricus were inhibited by five pyrethroid insecticides. Inhibition on Na+ - K+ ATPase was higher than that of Ca2+ - Mg2+ 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.