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枸杞蚜虫是危害枸杞产量和质量的重要害虫。本文采用药膜法测定了4种杀虫剂对枸杞蚜虫的毒力,同时采用分光光度法测定了枸杞蚜虫羧酸酯酶(Car E)的特性和杀虫剂对其的抑制作用。结果表明,灭多威对枸杞蚜虫的毒力最大,LC50为0.640mg/L;氧化乐果毒力最小,LC50为18.783mg/L;异丙威和三唑磷居中,LC50分别为6.696mg/L和8.201mg/L。α-乙酸萘酯为枸杞蚜虫羧酸酯酶的最适底物,以α-乙酸萘酯为底物反应的Km值为0.050 3±0.004 27μmol/L,Vmax值为0.950 7±0.020 8μmol/min·mg。4种杀虫剂对枸杞蚜虫羧酸酯酶(Car E)体外抑制结果表明,2种有机磷杀虫剂对Car E的抑制大于两种氨基甲酸酯类杀虫剂。三唑磷和氧化乐果抑制中浓度(I50)分别为0.629 5×10-5mol/L和0.150 7×10-3mol/L,异丙威和灭多威抑制中浓度(I50)为0.229 6×10-3mol/L和1.023×10-3mol/L。同时,4种抑制剂对枸杞蚜虫羧酸酯酶抑制的时间动力学曲线不同,其中三唑磷、氧乐果、灭多威比较相似,在2min内抑制率可达60%以上,之后缓慢增加;异丙威在2-10min内,抑制率由10%增加到60%,之后增加速度趋缓。
Wolfberry aphids is an important pest endangers the yield and quality of Chinese wolfberry. In this paper, the toxicity of four kinds of insecticides to wolfberry aphids was determined by the membrane method. At the same time, the spectrophotometric method was used to determine the characteristics of carboxylesterase (CarE) of Lycium barbarum and the insecticide’s inhibition. The results showed that methomyl had the highest virulence to wolfberry aphid with the LC50 of 0.640mg / L, the lowest toxicity of omethoate with LC50 of 18.783mg / L, the isopriva and triazophos with LC50 of 6.696mg / L and 8.201 mg / L. The α-naphthyl acetate was the most suitable substrate for the carboxylesterase of Lycium barbarum. The Km value of α-naphthyl acetate as substrate was 0.050 3 ± 0.004 27μmol / L and the Vmax was 0.950 7 ± 0.020 8μmol / min · Mg. The results of in vitro inhibition of CarE by four kinds of insecticides on Carbex aphid Carboxylesterase showed that the two organophosphate pesticides inhibited carE more than two kinds of carbamate insecticides. The inhibitory concentrations of triazophos and omethoate (I50) were 0.629 5 × 10-5 mol / L and 0.150 7 × 10-3 mol / L respectively, and the median inhibitory concentration (I50) of isoprocarb and methomyl was 0.229 6 × 10-3 mol / L and 1.023 × 10-3 mol / L. At the same time, the four kinds of inhibitors have different kinetic curves on the inhibition of carboxylesterase by Lycium barbarum, among which, triazophos, omethoate and methomyl are similar, with the inhibition rate up to 60% within 2min, then slowly increasing ; Isoprocarb within 2-10min, the inhibition rate increased from 10% to 60%, then increase the rate of slowing.