【作者】 刘永杰；

【导师】 沈晋良；

【作者基本信息】 南京农业大学 ， 农药学， 2002， 博士

【摘要】 甜菜夜蛾是一种世界性分布的重要农业害虫，可为害蔬菜、棉花、果树、观赏植物等，过去20多年在许多国家严重发生危害。 室内测定了6个地区甜菜夜蛾幼虫对8种杀虫剂的抗药性。用点滴法测定深圳、湖南、上海、常熟及南京种群3龄幼虫对5种杀虫剂的的抗性，结果表明：对高效氯氰菊酯抗性最高，属极高水平抗性（172.1～408.7倍）；其次为百树菊酯（42.7～109.8倍）和毒死蜱（21.0～50.3倍），属中等～高水平抗性；而灭多威（2.3～21.0倍）和辛硫磷（3.0～15.1倍）抗性最低，属敏感～中等水平抗性；河北种群除对高效氯氰菊酯为低水平抗性（5.1倍）外，对其余药剂均属敏感（0.6～2.0倍）。用浸叶法测定6个地区甜菜夜蛾初孵幼虫对3种杀虫剂的抗性，结果表明：除深圳种群对抑太保为低水平抗性（6.4倍）外，其余种群1龄幼虫对抑太保（0.7～3.4倍）、拉威因（1.5～3.9倍）及米螨（1.0～3.1倍）均属敏感～敏感性下降阶段阶段。 用点滴法（触杀作用）、浸叶法（触杀和胃毒作用）及叶片夹毒法（胃毒作用）等3种方法分别测定了采自南京江浦甜菜夜蛾抗性品系3龄或5龄幼虫对功夫菊酯的抗性，结果表明，抗性水平的次序为3龄幼虫点滴法（抗性倍数为5499.5倍）和5龄幼虫点滴法（3973.2倍）＞3龄幼虫浸叶法（1041.6倍）＞5龄幼虫叶片夹毒法（24.7倍），点滴法、浸叶法及叶片夹毒法间抗性倍数之比依次为222.7～160.9:42.2:1。上述结果进一步说明，经穿透幼虫表皮的触杀毒力所引起的抗性高于经口器、表皮的胃毒毒力、触杀毒力所引起的抗性，更高于经口器的胃毒毒力所引起的抗性。用¹⁴C标记功夫菊酯测定甜菜夜蛾抗性和敏感品系5龄幼虫表皮穿透率结果表明，处理后1小时，抗性晶系的表皮穿透率与敏感品系之间差异不显著；处理后2小时，在两品系间就存在明显差异，抗性品系的表皮穿透率（8.5％）稍慢于敏感品系的穿透率（13.2％）；处理后8小时，抗性品系的表皮穿透率（22.1％）明显慢于敏感品系的穿透率（39.8％），功夫菊酯对抗性品系5龄幼虫的表皮穿透率仅为敏感品系幼虫表皮穿透率的55.5％。上述结果证实表皮穿透率的降低是甜菜夜蛾对功夫菊酯产生抗性的重要原因之一。 用甜菜夜蛾敏感和抗性品系3龄幼虫测定多功能氧化酶抑制剂PBO、氧化酶和酯酶抑制剂SV₁、酯酶抑制剂DEF及谷胱甘肽转移酶抑制剂DEM对功夫菊酯 摘要的增效作用，结果表明：用敏感品系幼虫测定上述酶抑制剂对功夫菊酯分别增效2．3、1．3、2．9及1．5倍，而抗性品系分别增效32．5、19二3、6．6及3．5倍，抗性品系增效倍数与敏感品系增效倍数之比值分别为14．l、14．8、2．3及2．3倍。这表明多功能氧化酶抑制剂 PBO对功夫菊酯的增效作用最明显门．l倍＊是甜菜夜蛾对功夫菊酯抗性的主要生化代谢机理，而酯酶抑制剂DEF及谷脱甘肽转移酶抑制剂DEM对功夫菊酯的增效作用（2．3倍）显著低于册，因此，与甜菜夜蛾对功夫菊酯抗性的关系不大。以3龄幼虫整体匀浆为母液，测定和比较甜菜夜蛾敏感和抗性品系酯酶和谷肤甘肽转移酶的活性，结果表明，抗性品系酯酶和谷眺甘肽转移酶的活性分别为敏感品系的 1．05倍和 0．gi倍，两品系间酯酶和谷眯甘肽转移酶的活性没有显著差异，进一步证明甜菜夜蛾对功夫菊酯的抗性与酯酶和谷肌甘肽转移酶无关。以解剖5龄幼虫的中肠匀浆液为母液，测定抗性和敏感品系甜菜夜蛾的多功能氧化酶卜脱甲基活性分别为 0．1620和0．1708 nmol／mgpr／min，抗性品系的酶活性为敏感品系的1．05倍，两者差异也不显著，表明甜菜夜蛾对功夫菊酯的抗性与多功能氧化酶 卜脱甲基作用无关。 甜菜夜蛾抗性和敏感品系相对适合度研究结果表明：与敏感品系相比，甜菜夜蛾对功夫菊酯抗性品系幼虫的发育历期延长、蛹重减轻、化蛹率和产卵量降低，抗性品系适合度仅为敏感品系的0．61，即存在明显的生存劣势。抗性遗传的研究结果表明：甜菜夜蛾抗性和敏感品系正交F；（R。XS＊和反交厂·0。XS。）后代3龄幼虫的毒力（LD。。）分别为0．0764（0．0534～0．1114）和0．0906 门．0671～0．1213)u g／头，两者差异不显著门5％置信限重叠人 表明酣菜夜蛾对功夫菊酯的抗性为常染色体遗传，与性连锁无关。按 Stone门)报道的公式，计算得正交吓l)和反交吓；’)的显性度D值分别为 0．61和 0．43，表明抗性的主基因为不完全显性(0＜0＜1人测得回交SC（厂。X S＊对功夫菊酯的反应曲线在死亡率 50％处没有出现明显平坡，自交 F。（F；。X F；；）对功夫菊酯的反应曲线在死亡率25％或75％处也没有明显平坡，证明抗性为多基因遗传。 用浸叶法测定米螨对常熟甜菜夜蛾种群幼虫的毒力（LC。。），结果表明：其毒力次序为 1．3819（2龄）＞1．4166）（1龄）＞4．6585（3龄）＞6．8203mg／L（4龄）。室内用人工饲料感染法连续筛选甜菜夜蛾深圳种群初孵幼虫对米螨的抗性，结果表明：经8代筛选，抗性仅上升0．43倍，甜菜夜蛾对米螨的抗性风险似乎较小。更多还原

【Abstract】 Beet armyworm, Spodoptera exigua (Hubner), is a worldwide dsitributed polyphagous pest on various cultivated crops, including vegetables, cotton, fruit trees, ornamentals, and so on. In past two decades S. exigua has emerged as a serious pest in many countries.Resistance to 8 insecticides in six field populations of beet armyworm, Spodoptera exigua (Hubner), was evaluated in laboratory. The results determined by topical application showed that 3rd instar larvae of these populations collected from Shenzhen City, Guangdong Province, Hengyang City, Hunan Province, Shanghai City, Changshu and Nanjing City, Jiangsu Province developed high levels of resistance to high effect cypermethrin with 172.1-408.7 folds, moderate-high levels to cyfluthrin with 42.7- 109.8 folds and to chlorpyrifos with 21.0-50.3 fold, suseptibile - moderate levels to methomyl with 2.3-21.0 folds and to phoxim with 3.0-15.1 folds. The population from Longrao County, Hebei Province had only low level of resistance to high effect cypermethrin with 5.1 folds, but susceptible to other insecticides. The results tested by leaf-dipping method showed that first instar larvae of all tested populations was susceptible to chlorfuazuron(0.7-3.4 folds), thoidicarb(1.5 - 3.9 folds) and tebufenozide (1.0-3.1 folds) except that the population from Shenzhen area had low level of resistance to chlorfuazuron(6.4 folds) .Resistance to cyhalothrin in beet armyworm, Spodoptera exigua, collected from Jiangpu County, Nanjing, Jiangsu Province was determined by three bioassay methods. The results indicated that the sequence of resistance levels was topical application for 3rd and 5th instar larvae (5499.5- and 3973.2-fold)>leave-dipped method for 3rd instar larvae (1041.6-fold) > leave-sandwich-poison method for 5th instar larvae (24.7-fold), ratio of their resistance levels was 222.7-160.9:42.2:1.The results above demonstrated that resistance levels caused by contact toxicity through cuticular penetration higher than that by stomach and contact toxicity through mouth and cuticular penetration, even much higher than that by stomach toxicity through mouth. The rate of cuticular penetration of I4C-cyhalothrin in 5th instar larvae of the resistant and susceptible strains was determed. The results indicated that the rate of cuticular penetration in resistant strain was nearly the same in the susceptible strain, but after 2h treatment the rat (8.5%) in the resistant strain was slower than that (13.2%) in the susceptible strain, and after 8h treatment the rat (22.1%) in the resistant strain was much slower than that (39.8%) in the susceptible strain, only about 55.5% of penetration rate in the susceptible strain. It is safe to say that delayed cuticular penetration was one of the important mechanism responsible for this resistance.Biochemical mechanism of resistance in beet armyworm to cyhalothrin has been investigated by enzyme synergists (PBO, SVi, DBF and DEM) and enzyme activities assays of esterase > glutathione S-transferase and microsomal O-demethylase. The synergism ratios of PBO, SVi, DEF and DEM to cyhalothrin were 2.3, 1.3, 2.9 and 1.5 folds in susceptible strain, respectively; 32.5-,19.3-,6.6- and 3.5-fold in resistant strain, respectively. Ratios between resistant and susceptible strain were 14.4, 14.8, 2.3 and 2.3 folds, respectively. The result shows that synergism to cyhalothrin by PBO was the most distinct. This implied that mixed-function oxidase was involved in the resistance to cyhalothrin. Synergism to cyhalothrin by DEF and DEM was not much significant. The ratios of enzymatic activity of esterase, glutathione S-transferase and microsomal O-demethylase in susceptible and resistant strains were 1.05-, 0.91- and 1.05-fold, respectively, no significant difference. All these indicated that detoxification enzymes such as esterase, glutathione S-transferase and microsomal O-demethylase contributed little to the resistance of beet armyworm to cyhalothrin.The relative fitness between resistant and susceptible strains to cyhalothrin in beet armywor更多还原