Indoor Toxicity of Emamectin Benzoate and Chlorantraniliprole Against Spodoptera litura and Their Residues on Lotus Plants

Spodoptera litura is the most threatening pest in lotus production,seriously affecting the lotus yield and quality.Emamectin benzoate and chlorantraniliprole,the main insecticides for controlling S.litura on vegetables,are widely used by farmers to control S.litura on lotus plants.To determine the application concentrations,control effects,and safety of the two insecticides in lotus fields,indoor experiments were conducted to determine the control effects of 200 g/L chlorantraniliprole(SC)and 5%emamectin benzoate(WDG),and the residues of the two insecticides in the water,lotus leaves,and lotus seeds after field application were determined by HPLC-MS/MS.The indoor experiment results showed that chlorantraniliprole and emamectin benzoate both had good control effects on S.litura,with the median lethal concentrations(LC50)of 17.700 and 1.694 mg/L,respectively.After unmanned aerial vehicle spraying of emamectin benzoate at 20 g/667m^(2),there was no residue of emamectin benzoate in the water or lotus leaves after 5 d.After spraying of chlorantraniliprole at 20 mL/667m^(2),the residual amounts in the water and lotus leaves after 9 d were 0.005 and 0.007 mg/L,respectively.No residue of the two insecticides was detected in lotus seeds(dry and fresh)2 h after spraying.Therefore,it was recommended that chlorantraniliprole and emamectin benzoate can be used to control S.litura in lotus fields during the growth period,while attention should be paid to the application interval for safety.Considering the safe harvesting of lotus seeds and leaves,it was recommended that the preharvest intervals of chlorantraniliprole and 5%emamectin benzoate should be 9 d.

Biological activities of Solanum pseudocapsicum(Solanaceae)against cotton bollworm,Helicoverpa armigera Hübner and armyworm,Spodoptera litura Fabricius(Lepidotera:Noctuidae)

Objective:To evaluate the antifeedant,insecticidal and growth inhibition activities of Solanum pseudocapsicum(S.pseudocapsicum)seed extracts against Spodoptera litura(S.litura)and Helicotverpa armigera(H.armigera).Methods:Hcxane,diethyl cther,dichloromethanc and ethyl acetate seed extracts were prepared and tested for autifeedant,insecticidal and growth inhibitory activities against fourth instar larvae of&litura and H.armigera.Results:Ethyl acetate extract showed promising antifeedant and insecticidal activities against S.litura and H.armigera.Percentage of deformed larvae,pupae and adults were maximum in treatment of ethyl acetate extract.Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae.Conclusions:Ethyl acetate extracts of S.pseudocapsicum,showed higher efficiency of antifeedant,insecticidal and growth inhibition activities.Hence,it can be used to controll agricultural insect pests,S.litura and H.armigera.

Detoxification of insecticides, allechemicals and heavy metals by glutathione S-transferase SIGSTE1 in the gut of Spodoptera litura

Insect glutathione S-transferases （GSTs） play important roles in detoxifying toxic compounds and eliminating oxidative stress caused by these compounds. In this study, detoxification activity of the epsilon GST S1GSTE1 in Spodoptera litura was analyzed for several insecticides and heavy metals. S1GSTE1 was significantly up-regulated by chlor- pyrifos and xanthotoxin in the midgut of S. litura. The recombinant S1GSTE1 had Vmax （reaction rate of the enzyme saturated with the substrate） and Km （michaelis constant and equals to the substrate concentration at half of the maximum reaction rate of the enzyme） values of 27.95 ± 0.88μmol/min/mg and 0.87 ± 0.028 mmol/L for glutathione, respec- tively, and Vmax and Km values of 22.96 ± 0,78μmol/min/mg and 0.83 ± 0.106 mmol/L for 1-chloro-2,4-dinitrobenzene, respectively. In vitro enzyme indirect activity assay showed that the recombinant S1GSTE 1 possessed high binding activities to the insecticides chlor- pyrifos, deltamethrin, malathion, phoxim and dichloro-diphenyl-trichloroethane （DDT）. S1GSTE1 showed higher binding activity to toxic heavy metals cadmium, chromium and lead than copper and zinc that are required for insect normal growth. Western blot analysis showed that S1GSTE1 was induced in the gut of larvae fed with chlorpyrifos or cadmium. S1GSTE1 also showed high peroxidase activity. All the results together indicate that S1G- STE1 may play an important role in the gut orS. litura to protect the insect from the toxic effects of these compounds and heavy metals.

Identification of a novel cytochrome P450 CYP321B1 gene from tobacco cutworm （Spodoptera litura） and RNA interference to evaluate its role in commonly used insecticides

Insect cytochrome P450 monooxygenases （CYPs or P450s） play an important role in detoxifying insecticides leading to resistance in insect populations. A polyphagous pest, Spodoptera litura, has developed resistance to a wide range of insecticides. In the present study, a novel P450 gene, CYP321B1, was cloned from S. litura. The function of CYP321B1 was assessed using RNA interference （RNAi） and monitoring resistance levels for three commonly used insecticides, including chlorpyrifos, β-cypermethrin and methomyl. The full-length complementary DNA sequence of CYP321B1 is 1814 bp long with an open reading frame of 1 488 bp encoding 495 amino acid residues. Quantitative reverse-transcriptase polymerase chain reaction analyses during larval and pupal develop- ment indicated that CYP321B1 expression was highest in the midgut of fifth-instar larvae, followed by fat body and cuticle. The expression of CYP321B1 in the midgut was up- regulated by chlorpyrifos,β-cypermethrin and methomyl with both lethal concentration at 15% （LC15） （50, 100 and 150 μg/mL, respectively） and 50%（LC50） dosages （100,200 and 300μg/mL, respectively）. Addition of piperonyl butoxide （PBO） significantly increased the toxicity ofchlorpyrifos,β-cypermethrin and methomyl to S. litura, suggesting a marked synergism of the three insecticides with PBO and P450-mediated detoxification. RNAi- mediated silencing of CYP321B1 further increased mortality by 25.6% and 38.9% when the fifth-instar larvae were exposed to chlorpyrifos and β-cypermethrin, respectively, at the LCso dose levels. The results demonstrate that CYP321B1 might play an important role in chlorpyrifos and β-cypermethrin detoxification in S. litura.

Exposure to herbicides reduces larval sensitivity to insecticides in Spodoptera litura (Lepidoptera: Noctuidae)

Herbicides and insecticides are widely used in modern agriculture. It has been reported in various studies that application of insecticides can increase tolerance of herbivorous insects to insecticides. However, limited information exists on susceptibility to insecticides when insects are exposed to herbicides. This study was conducted to investigate the potential impact of the herbicides trifluralin and 2-methyl-4-chlorophenoxyacetic acid sodium salt (MCPA-Na) on the susceptibility of the nocturnal moth Spodoptera litura to the insecticides X-cyhalothrin, phoxim and bifenthrin. We found that larvae exposed to trifluralin or MCPA-Na became significantly less susceptible to both insecticides than nonexposed control larvae. Herbicide-treated larvae did not show altered growth under the used test conditions. However, heads of herbicide-treated larvae showed increased expression of the acetylcholinesterase genes SI Ace I and SI Ace 2. Moreover, the fat body and midgut of herbicide-treated larvae displayed elevated expression of detoxification genes (the carboxylesterase gene SI CarE;the glutathione S-transferase genes SlGSTe2 and SlGSTe3\ the cytochrome P450 monooxygenase genes CYP6B48, CYP9A40 and CYP321B1). The CYP6B48 gene exhibited highest inducibility. In conclusion, the data of this study suggest that exposure of S. litura larvae to herbicides may stimulate detoxification mechanisms that compromise the efficacy of insecticides.

Bioactivity of Pseudocalymma alliaceum(Lam.)Sandwith(Bignoniaceae)against Spodoptera litura Fabricius and Helicoverpa armigera Hübner(Lepidotera:Noctuidae)

Objective:To evaluate the antifeedant,larvicidal and insect growth inhibitory activities of crude extracts of Pseudocalymma alliaceum tested against fourth instar larvae of Spodoptera litura(S.litura)and Helicoverpa armigera(H.armigera).Methods:Hexane,chloroform and ethyl acetate extracts were prepared and tested for antifeedant,insecticidal and growth inhibitory activities against fourth instar larvae of S.litura and H.armigera.Results:Ethyl acetate extract showed promising antifeedant,insecticidal activity against S.litura and H.armigera.Maximum percentage of deformed larvae,pupae and adults were found on treatment with ethyl acetate extract.Percentage of successful adult emergence was deteriorated by extract treated larvae.Ethyl acetate extracts of Pseudocalymma alliaceum,showed higher percentage of antifeedant,insecticidal and growth inhibition activities.Conclusions:This is the first report on S.litura and H.armigera.Further,the active compounds isolated from the ethyl acetate extracts will be useful for controlling economically important insect pests.

Geographic variation in cypermethrin insecticide resistance and morphometry in Spodoptera litura(Fabricius)(Lepidoptera:Noctuidae)

Objective:To find out the most resistant strain of Spodoptera litura(S.litura)from Tamil Nadu,Kerala and Karnataka by synthetic insecticide treatment.Methods:Using leaf disc no-choice method,the insects were tested with different doses for pesticides.The LC_(50)and LC_(90)values were calculated by probit analysis.Results:In the insect bioassay,the cypermethrin insecticide showed significantly higher LC_(50)values of 14.699 g/L and 15.738 g/L against the Tamil Nadu and Kerala S.litura insect cultures respectively.The body length of 2nd,3rd and 4th instar larvae were significantly higher(P≤0.05)in TTP insect population[(19.2±2.3)mm,(28.05±3.20)mm,(36.1±2.0)mm],when compared with KTK[(18.5±2.7)mm,(23.38±2.00)mm,(31.75±2.70)mm]and control,KBB[(15.65±2.30)mm,(23.65±2.70)mm,(33.2±2.2)mm]populations.The body breadth of 3rd instar larvae was significantly higher(P≤0.05)in TTP insect population(4.9±1.1)mm,when compared with KTK(3.93±0.80)mm and control,KBB(3.65±0.70)mm populations.Conclusions:The present study clearly showed that field collected strains were highly resistant when compared to control.Based on our study,we conclude that reduced use of synthetic pesticides is necessary and IPM is a better way to reduce the development of pesticide resistance among strains of S.litura.

香葱主要虫害防治药剂的筛选

为了筛选防治香葱蓟马、斑潜蝇、斜纹夜蛾的高效安全药剂,通过田间药效试验测定不同杀虫剂对3种害虫的防治效果。结果表明,60 g/L乙基多杀菌素SC对蓟马的防效较好,防效为88.40%~95.93%;60%噻虫·灭蝇胺WG对斑潜蝇的防效较好,防效为81.02%~87.26%;35%氯虫苯甲酰胺WG对斜纹夜蛾的防效较好,防效为88.01%~92.53%,为香葱主要虫害田间防控提供高效药剂。

斜纹夜蛾谷胱甘肽S-转移酶SlGSTS4对拟除虫菊酯和有机磷类杀虫剂代谢和抗氧化活性

【目的】探究斜纹夜蛾Spodoptera litura谷胱甘肽S-转移酶SlGSTS4在拟除虫菊酯和有机磷类杀虫剂抗性中的作用。【方法】构建pET-26b(+)/SlGSTs4表达载体,将其在大肠杆菌Escherichia coli中异源表达,获得SlGSTS4重组蛋白,测定其对模式底物1-氯-2,4-二硝基苯(1-chlom-2,4-dinitrobenzene,CDNB)的米氏常数(K_(m))和最大反应速度(V_(max));采用超高效液相色谱(ultra-performance liquid chromatography,UPLC)测定重组蛋白SlGSTS4和表达SlGSTS4的大肠杆菌对拟除虫菊酯类杀虫剂(氰戊菊酯、高效氯氰菊酯和功夫菊酯)和有机磷类杀虫剂(毒死蜱和辛硫磷)的代谢率,并通过滤纸片抑菌圈试验测定SlGSTS4在过氧化氢异丙苯胁迫下的抗氧化活性。【结果】重组蛋白SlGSTS4对CDNB的V_(max)和K_(m)值分别为(13.8±2.3)nmol/(min·mg)和(1.66±0.1)mmol/L。UPLC结果表明,与对照相比,SlGSTS4重组蛋白仅对功夫菊酯有一定的代谢率(4.9%),而对氰戊菊酯、高效氯氰菊酯、辛硫磷和毒死蜱无代谢活性;转化SlGSTS4的大肠杆菌对氰戊菊酯、高效氯氰菊酯、功夫菊酯、毒死蜱和辛硫磷的代谢残留量峰面积均无明显变化,并且可以显著降低抑菌圈直径。【结论】SlGSTS4对拟除虫菊酯和有机磷类杀虫剂无直接代谢活性,具有明显的抗氧化活性。本研究结果丰富了对斜纹夜蛾GSTs Sigma家族基因的功能认知,有助于阐明SlGSTS4在斜纹夜蛾对拟除虫菊酯和有机磷类杀虫剂抗性中的功能。

骆驼蓬等植物提取物杀虫活性研究

以采自新疆的植物骆驼蓬、黄花蒿、艾蒿和采自云南恶性杂草紫茎泽兰为植物材料,研究其提取物对萝卜蚜、菜粉蝶、斜纹夜蛾的生物活性.结果表明,骆驼蓬甲醇提取物10000μg/mL处理后24和48h,萝卜蚜校正死亡率分别为93.07%和96 36%;处理后24h,对菜粉蝶5龄幼虫和斜纹夜蛾3龄幼虫的非选择性拒食率分别为90 81%和72 13%,均高于其他3种植物甲醇提取物.盆栽试验表明,骆驼蓬甲醇提取物对萝卜蚜防治效果良好,以10000μg/mL喷施处理后24和48h,防效可达71 34%和89 82%.

斜纹夜蛾抗药性监测及茚虫威对其解毒代谢酶的影响

【目的】斜纹夜蛾Spodoptera litura（Fabricius）是主要的农业害虫之一。本研究旨在明确该害虫在湖南省5个主要蔬菜种植区的抗药性水平,并探讨该害虫对茚虫威的抗性与解毒代谢酶活性之间的关系,为斜纹夜蛾有效防控及抗性治理提供依据。【方法】采用浸叶法测定了2014-2016年湖南5地斜纹夜蛾田间种群对10种杀虫剂的抗性水平;将斜纹夜蛾敏感种群3龄幼虫在死亡率40%-70%的选择压下用茚虫威进行汰选,比较了斜纹夜蛾敏感种群和抗茚虫威种群的羧酸酯酶、谷胱甘肽S-转移酶和多功能氧化酶对硝基苯甲醚O-脱甲基活性。【结果】湖南5地斜纹夜蛾田间种群对有机磷类杀虫剂产生了26.9-220.2倍的抗性,对氨基甲酸酯类杀虫剂产生了68.3-890.8倍的抗性,对拟除虫菊酯类杀虫剂产生了21.0-267.2倍的抗性,对相对较新型杀虫剂（甲维盐、阿维菌素、茚虫威和溴虫腈）产生了5.2-53.4倍的抗性。经茚虫威汰选后第14代[抗性倍数（resistance ratio,RR）=26.43]斜纹夜蛾羧酸酯酶、谷胱甘肽S-转移酶和对硝基苯甲醚O-脱甲基酶活性分别上升2.86,1.01和1.83倍。【结论】斜纹夜蛾对多种药剂产生了不同水平的抗性,斜纹夜蛾幼虫羧酸酯酶和对硝基苯甲醚O-脱甲基活性增强可能是斜纹夜蛾对茚虫威的抗性上升的重要因素。

二十六种杀虫剂对不同龄期草地贪夜蛾幼虫的室内毒力

2019年初,草地贪夜蛾(Spodoptera frugiperda)入侵中国云南地区并迅速扩散。为筛选杀虫效果较好的药剂,室内测定了26种商品药剂对草地贪夜蛾初孵、3龄和5龄幼虫的毒力。结果表明,除6%鱼藤酮微乳剂、0.5%藜芦碱乳油外,其他药剂对初孵幼虫72 h后的校正死亡率均在70%以上。与初孵幼虫相比,大部分药剂对3龄幼虫的毒力有所下降,包括4.5%高效氯氟氰菊酯乳油、1.8%阿维菌素微乳剂、20%氯虫苯甲酰胺悬浮剂、0.5%苦参碱水剂等在内的11种药剂对3龄幼虫72 h后的校正死亡率均在70%以下。选取18种对3龄幼虫效果相对较好的药剂测定其对5龄幼虫的毒力,结果显示,除30%噻嗪·毒死蜱乳油、1.8%阿维菌素微乳剂、3.2%高氯·甲维盐微乳剂、56%阿维·炔螨特微乳剂、20%氯虫苯甲酰胺悬浮剂和10%氟苯虫酰胺悬浮剂外,其他12种药剂对5龄幼虫的校正死亡率均高于70%,包括6%甲维·虫螨腈乳油、44%氯氰·丙溴磷乳油、25%丙溴·灭多威乳油、15%茚虫威悬浮剂、30亿PIB·mL-1甘蓝夜蛾核型多角体病毒悬浮剂、25%甲维·灭幼脲悬浮剂、2%甲氨基阿维菌素苯甲酸盐微乳剂、45%毒死蜱乳油、34%乙基·甲氧虫悬浮剂、5%虱螨脲乳油、40%氟虫·乙多素水分散粒剂、1%苦皮藤素乳油。

浙江菜区斜纹夜蛾对几类杀虫剂的敏感性

为明确浙江菜区斜纹夜蛾对主要杀虫剂的抗药性发展趋势，采集了浙江三门和萧山地区田间斜纹夜蛾，监测其对11种杀虫剂的敏感性水平。结果表明，三门种群和萧山种群对这些杀虫剂的敏感性存在明显差异，且萧山种群对测试药剂的敏感性高于三门种群。参考抗性诊断剂量（田间推荐浓度）处理后存活率和11种杀虫剂LC99致死浓度与田间推荐浓度的比值，推断三门种群对氯虫苯甲酰胺和溴虫腈敏感，对茚虫威、甲氨基阿维菌素苯甲酸盐、啶虫隆、丁醚脲和多杀菌素的敏感性下降，对虫酰肼、乙基多杀菌素、阿维菌素和高效氯氰菊酯已产生抗性；同样，萧山种群对氯虫苯甲酰胺、溴虫腈和多杀菌素敏感，对甲氨基阿维菌素苯甲酸盐、丁醚脲、啶虫隆、乙基多杀菌素、茚虫威、阿维菌素敏感性下降，对虫酰肼和高效氯氰菊酯产生抗性。因此，浙江菜区斜纹夜蛾对大部分监测杀虫剂的抗性正在形成，已产生抗性的高效氯氰菊酯、阿维菌素、虫酰肼应暂停使用1～2年；其余药剂则需要控制用药次数和采用不同种类杀虫剂轮用、混用的方式以延缓抗药性的产生。

烟碱和芸香苷对斜纹夜蛾药剂敏感性及相关酶活性的影响

以在人工饲料中添加植物次生物质的方法,研究了取食不同含量烟碱、芸香苷的斜纹夜蛾Spodoptera litura 3龄幼虫对银纹夜蛾核多角体病毒(AucaNPV)、氟虫腈及多杀菌素的敏感性,同时测定了各处理组幼虫体内羧酸酯酶和谷胱甘肽转移酶的活性。结果表明:烟碱能明显提高斜纹夜蛾对3种药剂的敏感性,且与剂量成正相关;低浓度的芸香苷可增加试虫对药剂的敏感性,但随其剂量的升高敏感性降低。两种次生物质均能不同程度地抑制斜纹夜蛾羧酸酯酶的活性,但可诱导谷胱甘肽转移酶的活性。

不同种类杀虫剂对斜纹夜蛾的药效评价

通过室内测定和田间药效试验，评价了有机磷、拟除虫菊酯、氨基甲酸酯、昆虫生长调节剂、苯基吡唑类、抗生素及植物性农药等７大类杀虫剂对斜纹夜蛾的效应，结果表明，毒死蜱、保得、万灵及抑太保对斜纹夜蛾具有优良的防效。

常规杀虫剂组合对草地贪夜蛾的防治效果及其经济性评价

比较7种常规杀虫剂组合对玉米田草地贪夜蛾的防效、喇叭口受害率以及用药经济性关系。表明了乙基多杀菌素SC+苏云金杆菌SC、甲维盐EC+苏云金杆菌SC和甲维盐EC+虱螨脲EC这3种组合,对草地贪夜蛾防效较好,14 d后,对低龄幼虫防效达93.7%~95.69%,高龄幼虫防效达93.49%~97.07%。乙基多杀菌素SC+苏云金杆菌SC、甲维盐EC+苏云金杆菌SC、甲维盐EC+虱螨脲EC和氯氰·辛硫磷EC+虱螨脲EC等组合,在药后14 d喇叭口受害率显著降低,仅8.33%~11.67%。对防效和植株止损投入比分析认为,考虑用药经济性,推荐氯氰·辛硫磷EC+虱螨脲EC的处理组合,能获得较好的防效;在防治预算充足条件下,推荐甲维盐EC+苏云金杆菌SC、苏云金杆菌SC和甲维盐EC+虱螨脲EC能达到更好地防治目标。

斜纹夜蛾对氯氟氰菊酯不同抗性水平与解毒代谢酶的关系

为探讨斜纹夜蛾Spodoptera litura(Fabricius)对氯氟氰菊酯抗性水平与解毒代谢酶之间的关系,以泰安郊区对氯氟氰菊酯抗性为543.7倍的斜纹夜蛾田间种群为材料,研究了药剂汰选与否的抗性动态及不同抗性水平的解毒代谢酶活性变化。结果表明:室内继代饲养至第30代,不接触任何药剂的抗性下降至102.3倍,用氯氟氰菊酯汰选28代后,抗性上升到3049.3倍,而在药剂汰选至第14代,抗性已至2593.8倍时,停止用氯氟氰菊酯汰选,到第30代的抗性又降至786.3倍。表明斜纹夜蛾抗氯氟氰菊酯田间种群,在无药剂选择压力时抗性水平会显著下降,继续给予药剂汰选会使抗性水平显著上升。检测斜纹夜蛾田间种群5龄幼虫中肠酯酶和谷胱甘肽S-转移酶活性,发现与敏感种群有显著性差异,而多功能氧化酶O-脱甲基活性与敏感种群的差异不明显;给予氯氟氰菊酯药剂汰选,酯酶、谷胱甘肽S-转移酶和多功能氧化酶O-脱甲基3种酶的活性均呈显著增加趋势;停止用氯氟氰菊酯汰选后,3种酶的活性又呈显著下降趋势;不接触任何药剂,随着饲养世代数的增加,其酯酶和谷胱甘肽S-转移酶的活性也呈下降趋势。结果提示斜纹夜蛾幼虫酯酶、谷胱甘肽S-转移酶和多功能氧化酶O-脱甲基活性的提高是斜纹夜蛾对氯氟氰菊酯抗性上升的重要原因。

桔皮提取物对斜纹夜蛾与甜菜夜蛾幼虫的生物活性作用

室内测定了温州蜜桔桔皮乙醇提取物对斜纹夜蛾和甜菜夜蛾幼虫的生物活性.结果表明斜纹夜蛾和甜菜夜蛾幼虫取食桔皮提取物后食物消耗量、体重增长量下降,幼虫死亡率增加.提取物浓度越高,这些作用效果越明显.在相同浓度下,甜菜夜蛾幼虫的死亡率比斜纹夜蛾的高;甜菜夜蛾的生长抑制中浓度和非选择性拒食中浓度均比斜纹夜蛾的低;但在选择性试验中,甜菜夜蛾的拒食中浓度则比斜纹夜蛾的高.这些结果表明,桔皮提取物对甜菜夜蛾幼虫的生物活性总体上比对斜纹夜蛾的更好.

9种药剂对斜纹夜蛾的室内毒力与田间应用效果

通过室内毒力测定和田间药效试验,测定当前9种主流杀虫剂产品对斜纹夜蛾的防治效果。结果表明,甲维盐、茚虫威、虫螨腈和虫酰肼对斜纹夜蛾具有优良的防效,可作为防治斜纹夜蛾的首选药剂。Bt与多杀菌素的效果次之。阿维菌素、高效氯氰菊酯和毒死蜱对斜纹夜蛾已逐渐失去控制作用,在生产中应尽量少用、慎用。

氯氟氰菊酯对斜纹夜蛾抗性和敏感种群表皮穿透比较

【目的】研究证实斜纹夜蛾对氯氟氰菊酯的抗性是否与其表皮穿透率降低有关。【方法】分别采用点滴法、浸叶法和叶片夹毒法测定了斜纹夜蛾(Spodoptera litura Fabricius)对氯氟氰菊酯的抗性,用14C标记氯氟氰菊酯测定了斜纹夜蛾抗性和敏感种群3龄和5龄幼虫的表皮穿透率。【结果】采用3种方法测定结果表明,3龄幼虫抗性水平的次序为点滴法(抗性倍数为2765.4倍)>浸叶法(365.1倍)>叶片夹毒法(34.0倍),点滴法、浸叶法及叶片夹毒法间抗性倍数之比依次为81.3﹕10.7﹕1;5龄幼虫抗性水平的次序为点滴法(抗性倍数为2271.3倍)>浸叶法(257.2倍)>叶片夹毒法(20.2倍),点滴法、浸叶法及叶片夹毒法间抗性倍数之比依次为112.4﹕12.7﹕1。经穿透昆虫表皮的触杀毒力所引起的抗性高于经口器和表皮进入的胃毒毒力和触杀毒力之和所引起的抗性,更明显高于经口器进入的胃毒毒力所引起的抗性。同位素标记氯氟氰菊酯测定结果表明,处理后0.5h和1.0h,抗性种群和敏感种群间表皮穿透率差异不显著,处理后2h,两种群间的穿透率存在明显差异,至处理后8h,敏感种群3龄和5龄幼虫的表皮穿透率分别为46.3%和43.3%,抗性种群3龄和5龄幼虫的表皮穿透率分别为35.7%和29.1%,氯氟氰菊酯对抗性种群3龄幼虫的表皮穿透率仅为敏感种群幼虫穿透率的0.77倍,对5龄幼虫的表皮穿透率仅为敏感种群幼虫穿透率的0.67倍,抗性种群的穿透率明显慢于敏感种群的穿透率。【结论】斜纹夜蛾抗性种群对氯氟氰菊酯的表皮穿透率明显低于敏感种群,可能是其产生抗药性的一个原因。