溴氰虫酰胺亚致死剂量对甜菜夜蛾生长发育及体内解毒酶活性的影响

【目的】探讨溴氰虫酰胺对甜菜夜蛾 Spodoptera exigua (Hübner)的亚致死效应,为甜菜夜蛾的综合防治和溴氰虫酰胺的合理使用提供理论依据。【方法】采用饲料混毒法,测定溴氰虫酰胺对甜菜夜蛾3龄幼虫的毒力,确定其亚致死剂量（LC₁₀和LC₂₅）,并分别用该亚致死剂量处理甜菜夜蛾3龄幼虫,研究其对甜菜夜蛾的生长发育和体内3种解毒酶活性的影响。【结果】以LC₁₀ 和LC₂₅剂量处理甜菜夜蛾3龄幼虫后,幼虫生长受到显著抑制,虫重抑制率分别为11.55%和27.68%;LC₁₀和LC₂₅处理组3龄幼虫到化蛹天数分别比对照组延长0.07和0.20 d;化蛹率显著低于对照组（80.93%）,分别为63.89%和49.43%;成虫寿命显著缩短1.11 d和2.08 d;单雌产卵量和卵孵化率也低于对照组。亚致死剂量溴氰虫酰胺处理甜菜夜蛾幼虫后24-96 h,羧酸酯酶活性和谷胱甘肽-S转移酶活性表现出相似的变化趋势,呈先激活升高、后被抑制降低;而多功能氧化酶活性在药剂处理48 h和72 h均受到不同程度的抑制作用,这种抑制作用与浓度成正比。【结论】亚致死剂量的溴氰虫酰胺对甜菜夜蛾的生长发育有显著抑制作用,对其幼虫体内解毒酶活性也有不同程度的抑制作用。     

60Co-γ射线辐照对草地贪夜蛾自交种群发育与繁殖的影响

为了解60Co-γ射线辐照对草地贪夜蛾Spodoptera frugiperda成虫发育与繁殖的影响,本文以草地贪夜蛾6日龄蛹为对象,比较不同辐照剂量下草地贪夜蛾自交种群的羽化率、翅畸形率、寿命、产卵量以及子代卵孵化率的差异。结果表明,草地贪夜蛾成虫羽化率随着辐照剂量的升高而呈现降低的趋势,其中250 Gy、350 Gy、400 Gy以及500 Gy剂量辐照下的羽化率分别降低至72.8%、69.4%、69.4%和50.6%,与对照组（91.7%）相比差异显著;翅畸形率在400 Gy时值最高,为25.6%,但与对照组相比并无显著差异;其雌、雄成虫平均寿命均随辐照剂量的升高而缩短,且辐照后处理组雌、雄成虫寿命均显著低于对照组成虫寿命;雄虫日存活率在100 Gy、200 Gy、300 Gy和500 Gy处理条件下高于雌虫日存活率,而350 Gy和400 Gy处理组,以及对照组雌虫日存活率高于雄虫。草地贪夜蛾种群产卵雌虫数、单雌产卵量、及子代孵化情况与对照组相比差异显著,300~500 Gy的辐照剂量下,亲代没有卵粒产出,而100 Gy至250 Gy的辐照剂量下,产卵量显著降低,且在100 Gy时处理组的卵中有少量孵化。本文对草地贪夜蛾辐照不育剂量进行了初步评价,为今后实现该虫不育技术防治提供科学参考。     

虫酰肼对甜菜夜蛾汰选种群生长发育及生殖的影响

研究虫酰肼对甜菜夜蛾汰选种群生长发育及生殖的影响。结果显示:经虫酰肼处理后,甜菜夜蛾SS种群和RR种群卵的孵化抑制中浓度分别为179.38和160.71mg/kg,孵化幼虫的存活抑制中浓度分别为18.64和30.53mg/kg,虫酰肼对甜菜夜蛾卵的孵化率影响较小,而对孵化后幼虫的存活率影响较大。处理初孵幼虫6d后,2种群幼虫存活率及化蛹率随处理浓度的增加而降低,幼虫历期最高饲毒浓度与最低饲毒浓度相比分别延长了2.71d和6.19d,同一浓度下,RR种群幼虫历期比SS种群缩短了0.94～2.59d。处理甜菜夜蛾3龄幼虫12h后,随虫酰肼浓度的增加,2种群化蛹率逐渐降低,雌雄蛹重均有递减的趋势,雌蛹比例随浓度的增加变化较小,但SS种群雌蛹比例≤50.00%,而RR种群雌蛹比例≥50.00%,雌雄成虫羽化率总体上依次递减,处理浓度大于1.00mg/kg时虫酰肼对甜菜夜蛾成虫羽化的影响较大。     

母代性比对甜菜夜蛾实验种群繁殖潜力的影响

【目的】探明母代性比对甜菜夜蛾Spodoptera exigua(Hübner)实验种群繁殖及后代发展趋势的影响,为短期预测预报提供科学指导。【方法】在人工气候培养箱中(设置条件:温度28±1℃,光周期为16L:8D,相对湿度为70%±5%),研究甜菜夜蛾实验种群不同母代性比结构(♀:♂=1:1,1:2,1:3)对主要繁殖参数的影响。【结果】甜菜夜蛾成虫产卵历期随母代性比下降而缩短;种群产卵量随母代性比降低而减少;孵化率随母代性比降低而升高;每雌产卵量无差异,但雄蛾对卵及后代的贡献量却随着雌蛾比例的加大而显著提高;后代性比和雌蛹蛹重有随母代性比下降而上升的趋势。【结论】母代性比除对甜菜夜蛾雌蛾个体生殖能力影响较小,对雌蛾产卵历期、种群产卵量和孵化率、后代性比、后代雌蛹蛹重及母代雄蛾生殖贡献率均有显著影响。当以性诱剂诱集的雄虫数量为依据进行短期预测预报时,除了考虑雄虫的数量外,还有必要了解此时种群的性比结构,才能做出更准确的判断。     

噻虫啉亚致死剂量对斜纹夜蛾解毒酶系活性与生长繁殖的影响

【目的】斜纹夜蛾Spodoptera litura(Fabricius)是一种重要农业害虫,因药物、外界环境等选择压力的不同,造成其生长发育有所差异。噻虫啉是第二代氯代烟碱类杀虫剂,对昆虫烟碱型乙酰胆碱受体有很强的激动作用。本实验旨在探讨噻虫啉对斜纹夜蛾的亚致死效应,为斜纹夜蛾的综合防治和噻虫啉的合理使用提供理论依据。【方法】采用饲料混毒法,测定噻虫啉对斜纹夜蛾3龄幼虫的毒力,确定其亚致死剂量LC25和LC50。通过离体酶活性测定,分析噻虫啉亚致死剂量对斜纹夜蛾体内羧酸酯酶、谷胱甘肽-S转移酶和多功能氧化酶3种代谢解毒酶活性的影响。记录各个年龄阶段的生长发育、繁殖力以及种群增长等数据,应用特征年龄-龄期及两性生命表方法分析LC25和LC50剂量处理和对照的斜纹夜蛾子代(F1)两性生命表参数的差异。【结果】以LC25和LC50剂量处理斜纹夜蛾3龄幼虫48 h,羧酸酯酶活性均受到明显诱导,分别升高了14.2%和45.1%;谷胱甘肽-S转移酶活性受到明显的抑制,分别降低了9.8%和37.1%;而多功能氧化酶活性均低于对照,其抑制作用与浓度成正比,但差异不显著。LC25和LC50剂量处理斜纹夜蛾幼虫后,子代(F1)的成虫前期分别比对照延长了3.05 d和4.80 d,雄成虫寿命分别缩短了2.06 d和3.31 d,雌成虫寿命分别缩短了0.13 d和0.92 d;其单雌产卵量均显著减少,分别降低了17.7%和33.3%;化蛹率分别降低了10.7%和11.4%;两个处理的内禀增长率(r)、周限增长率(λ)和净增殖率(R0)均显著小于对照,平均世代时间(T)均明显延长。【结论】羧酸酯酶可能为斜纹夜蛾对噻虫啉解毒代谢过程中的主要解毒酶,在其后续抗性形成中起主要作用;噻虫啉亚致死剂量对斜纹夜蛾的生长、发育、繁殖有显著的抑制作用。     

转Bt基因玉米对甜菜夜蛾幼虫存活和发育的影响

在室内测定了2种转Cry1Ab基因的Bt玉米MON810和Bt11不同组织对甜菜夜蛾 Spodoptera exigua （Hübner）初孵幼虫以及心叶对4龄幼虫存活和发育的影响,在田间比较了甜菜夜蛾幼虫取食Bt 和非Bt玉米雌穗的存活和为害情况。结果表明,转Cry1Ab基因的Bt玉米的不同组织对甜菜夜蛾初孵幼虫都具有明显的杀虫活性,取食Bt玉米心叶、苞叶、籽粒时甜菜夜蛾均在幼虫期死亡; 取食MON810和Bt11雄穗的初孵幼虫化蛹率分别为5.2%和2.1%,羽化率为2.1%和1.0%;取食MON810和Bt11花丝的初孵幼虫化蛹率分别为1.0%和2.1%,但不能羽化。4龄幼虫取食MON810玉米心叶的化蛹率与对照差异不显著,而取食Bt11的化蛹率与对照差异显著; 取食两种Bt玉米心叶的４龄幼虫化蛹后的雌、雄蛹重和羽化率与对照组差异显著,但蛹期和平均单雌产卵量差异不显著,虽然对照组羽化的成虫平均产卵量高于Bt玉米组。田间接种初孵幼虫10 天后的调查结果表明,在MON810和Bt11玉米花丝上幼虫存活率分别为1.3%和0.3%, 而对照组分别为12.9%和16.2%;MON810和Bt11玉米雌穗被害率分别为18.3%和5.0%,而对照组分别为93.3%和95.0%,均显著低于对照组。     

甜菜夜蛾人工饲料及饲养技术研究

研究了人工继代繁殖甜菜夜蛾饲料配方及饲养方法 ,测定了各虫态发育历期、幼虫死亡率、化蛹率、羽化率、蛹畸形率及不同世代蛹重。采用改进的饲料配方饲养的深圳种群 ,第 2代幼虫死亡率、化蛹率、蛹畸形率、羽化率分别为 7 8% ,97 3 % ,2 7%和 93 8% ,第 2 ,5 ,9,1 2代平均单头蛹重分别为 1 1 9 7± 1 6 1 ,98 3± 1 1 4,94 3± 1 2 6和 82 4± 9 6mg,平均单雌产卵量分别为 1 1 3 7 2± 63 3 ,684 5± 5 3 7,45 6 9± 40 2和 3 91 7± 45 6粒。人工饲养的甜菜夜蛾 ,卵、幼虫、蛹、雌性成虫的发育历期分别为 2 5～3 5 ,1 0～ 1 2 5 ,7～ 8 5和 8～ 1 4天 ,完成一个世代需要 2 1～ 2 5天。     

氯虫苯甲酰胺亚致死剂量对蜂巢小甲虫生长发育和繁殖的影响

氯虫苯甲酰胺是我国蜂农防治蜂巢小甲虫Aethina tumida的主要杀虫剂。本研究旨在探讨氯虫苯甲酰胺对蜂巢小甲虫生长发育和繁殖的亚致死效应,为氯虫苯甲酰胺的合理使用提供一定的理论依据。本文采用饲料混毒法测定了氯虫苯甲酰胺对蜂巢小甲虫的毒力以及亚致死剂量LC10和LC25对蜂巢小甲虫生长发育和繁殖的影响。结果表明,氯虫苯甲酰胺对蜂巢小甲虫3龄初幼虫的LC50、LC25、LC10分别为5.193 μg/g、1.678 μg/g和2.865 μg/g。以氯虫苯甲酰胺亚致死剂量处理蜂巢小甲虫3龄初幼虫后,幼虫发育历期、雌预蛹期+蛹期、雄预蛹+蛹期均显著延长,且分别延长了3.38%和4.50%、10.51%和21.92%、5.26%和12.20%。LC10和LC25处理组幼虫的存活率均降低,尤其LC25处理组与对照组存在显著差异。LC10和LC25处理组漫游期幼虫重、初羽化雌虫重和初羽化雄虫重相比于对照均显著降低,且分别减轻了15.45%、21.54%、17.26%和13.47%、16.47%、16.46%。LC10和LC25处理组的产卵前期分别为7.96 d和7.47 d,比对照组显著缩短12.36 d和12.85 d;60 d内单雌产卵总量与对照组间无显著性差异,但在产卵期5~7 d时,LC25处理组的单雌产卵量显著增加。LC10和LC25处理组蜂巢小甲虫种群趋势指数低于对照组,但其种群趋势指数均远大于1,表明蜂巢小甲虫种群仍呈增长趋势,因此应加强蜂巢小甲虫的防控以及对氯虫苯甲酰胺的抗性监测。     

氰氟虫腙对小菜蛾阿维菌素抗性和敏感种群的亚致死效应(英文)

在实验室条件下采用生命表技术研究了氰氟虫腙亚致死剂量（LC₂₅）对小菜蛾Plutella xylostella阿维菌素抗性（AV-R）和敏感（AV-S）种群的亚致死效应, 旨在为小菜蛾对阿维菌素的抗性治理提供理论基础。结果表明： 氰氟虫腙对小菜蛾3龄幼虫抗性种群的LC₅₀和LC₂₅分别为0.24 mg/L和0.09 mg/L; 对敏感种群的LC₅₀和LC₂₅分别为0.20 mg/L和0.07 mg/L。氰氟虫腙亚致死剂量0.09 mg/L 处理小菜蛾后, 对处理代的影响表现为显著降低处理种群的化蛹率、 蛹重、 羽化率、 繁殖力; 明显延长蛹期, 缩短成虫产卵期和寿命; 对子代种群的影响表现为显著降低卵的孵化率、 幼虫各龄期的存活率, 延长发育历期。处理种群的内禀增长率（r_m）、 周限增长率（λ）和净增值率（R₀）显著低于对照种群（P<0.0001）。亚致死剂量的氰氟虫腙对小菜蛾抗性种群的影响大于敏感种群, 对处理代种群的影响大于子代种群。氰氟虫腙亚致死剂量可以极大地影响小菜蛾尤其是阿维菌素抗性种群的种群动态, 因此氰氟虫腙对于小菜蛾的抗性治理具有积极的作用。     

甜菜夜蛾的饲养方法介绍

介绍一种甜菜夜蛾的室内饲养方法 ,采用本方法累代饲养甜菜夜蛾 8代 ,平均蛹重达 1 1 2 .9mg ,平均化蛹率 97% ,平均羽化率为 91 .3% ,室内饲养结果表明 ,该饲养方法可用于室内大量饲养甜菜夜蛾     

溴氰菊酯亚致死浓度对烟草粉螟生物学特性的影响

为探讨溴氰菊酯对烟草粉螟的亚致死效应,本文采用烟叶浸渍法以溴氰菊酯亚致死浓度(LC 10和LC 25)胁迫烟草粉螟3龄幼虫,并通过年龄-龄期两性生命表的方法探究溴氰菊酯胁迫对烟草粉螟发育和繁殖的影响。结果显示:与对照相比,溴氰菊酯LC 10、LC 25处理F 0代的平均单雌产卵量显著下降;LC 25处理F 0代的产卵前期及总产卵前期明显长于对照;LC 25处理与LC 10处理和对照间,F 0代雌、雄虫寿命均差异显著;LC 10处理和LC 25处理F 1代与对照存活率明显下降,F 1代各处理间的卵、1龄幼虫、3龄幼虫、5龄幼虫、7龄幼虫和蛹的发育历期无显著差异;但LC 25处理组2龄、4龄、6龄幼虫历期比对照延长了且差异显著;LC 25处理组的成虫前期比对照组延长了且差异显著。同时LC 25处理的雌、雄虫寿命最短,但3个处理间差异不显著。研究表明,亚致死浓度的溴氰菊酯能够抑制烟草粉螟的生长发育和繁殖,以上研究结果可为田间用药控制烟草粉螟提供理论参考。     

东莨菪内酯对朱砂叶螨的驱避和产卵抑制活性

本研究采用叶碟浸渍法测定了东莨菪内酯对朱砂叶螨Tetranychus cinnabarinus(Biosduvals)雌成螨的触杀活性,采用选择性的半叶法测定了驱避活性,同时采用非选择性的全叶法测定了产卵抑制活性。结果表明,东莨菪内酯对朱砂叶螨雌成螨具有较好的触杀活性,采用叶碟浸渍法处理48h后的LC50为0.297mg·mL-1,LC30为0.105mg·mL-1,LC10为0.023mg·mL-1。采用LC50、LC30和LC103个浓度的东莨菪内酯处理雌成螨后,发现东莨菪内酯对雌成螨没有表现出明显的驱避活性,处理区和对照区24h和48h的着螨率均为50%左右;采用LC50和LC102个浓度处理雌成螨后表现出了一定的产卵抑制活性,平均产卵抑制率分别为23.02%和13.23%,而LC30对雌成螨的产卵量表现出了促进作用,平均产卵抑制率为-8.25%,这可能是由于毒物兴奋效应所致。本研究旨在为东莨菪内酯的进一步开发和应用奠定理论基础。     

毒死蜱亚致死剂量对二斑叶螨实验种群动态的影响

【目的】为探讨毒死蜱(Chlorpyrifos)对二斑叶螨Tetranychus urticae Koch种群动态的影响,室内研究了毒死蜱亚致死剂量对二斑叶螨实验种群成螨和若螨的生长发育、存活和繁殖情况的影响。【方法】用浸虫法进行测定,生命表方法分析亚致死效应。【结果】结果表明毒死蜱亚致死剂量LC25处理成螨后,雌成螨寿命、总产卵量、子代孵化率、性比与对照组无显著差异,其净增值率、内禀增长率、周限增长率以及种群加倍时间显著低于对照组。毒死蜱亚致死剂量LC25处理若螨后,总产卵量、净增值率、世代平均周期显著低于对照组,内禀增长率、周限增长率以及种群加倍时间与对照组无显著差异。扩散试验证明毒死蜱对二斑叶螨有较强的刺激扩散作用。【结论】以上结果说明毒死蜱亚致死剂量对不同发育阶段的二斑叶螨发育和繁殖的影响不同,毒死蜱对二斑叶螨的刺激扩散作用可能是引起二斑叶螨再猖獗的原因之一。     

滞育烟蚜茧蜂的亲代效应评价

【目的】烟蚜茧蜂Aphidius gifuensis Ashmead是可持续防控蚜虫的优良内寄生蜂,适宜的低温短光照可诱导其进入滞育,滞育后产品货架期长达120 d,对害虫生防意义重大。为深入探索滞育烟蚜茧蜂的亲代效应,分析滞育机理,提高滞育诱导效率,指导该天敌产品的贮存实践,开展本项研究。【方法】在室内测试了滞育烟蚜茧蜂F1代的羽化率、性比、成蜂寿命、滞育率、寄生力以及F2代的羽化率、性比等生物学指标,综合评价滞育烟蚜茧蜂的亲代效应。【结果】滞育经历对烟蚜茧蜂子代的部分生物学性状具有显著性影响,F1代雌蜂比例显著增加,滞育维持30 d后子代雌蜂比例由0.59上升至0.65;F2代雌蜂比例与CK无差别,维持在0.58左右;F1代滞育率显著升高,可由对照的44.75%提高至74.01%,滞育维持30 d后子代滞育率具升高趋势;F1代寄生力略增加,各处理形成的僵蚜数在117~129头间,但无显著性差异;F1代羽化率、子代成蜂寿命与CK相比无差异。【结论】烟蚜茧蜂具有较显著的滞育亲代效应,亲代滞育经历可显著提高子一代的滞育率,利于子代抵御不良环境胁迫,提高种群存活率。     

Assessment of Sublethal and Transgenerational Effects of Pirimicarb on the Wheat Aphids Rhopalosiphum padi and Sitobion avenae

The wheat aphids, Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius), are key pests on wheat crops worldwide. Management practices rely primarily on insecticides. The pirimicarb (carbamate) is used extensively as an effective insecticide to control these two aphids. In addition to the mortality caused by pirimicarb, various sublethal effects may occur in aphids when exposed to low lethal or sublethal doses. Understanding the general effect of pirimicarb on aphids could help increasing rational use of this insecticide. Under laboratory conditions, we assessed the sublethal effects of a low lethal concentration of pirimicarb (LC₂₅) on biological traits and acetylcholinesterase (AChE) activity of R. padi and S. avenae. Both direct and transgenerational effects, i.e. on parent and the F1 generations were assessed, respectively. We found that R. padi and S. avenae responded differentially to the LC₂₅ of pirimicarb. The parent generation of R. padi showed a 39% decrease in fecundity and multiple transgenerational effects were observed in the F1 generation; overall juvenile development, reproductive period, adult longevity and lifespan were longer than those of the control group. By contrast, LC₂₅ of pirimicarb showed almost no effects on S. avenae biological traits in both the parent and F1 generations; only the pre-reproductive duration was reduced in F1 generations. Demographic parameter estimates (e.g. r_m) showed similar trend, i.e. significant negative effect on R. padi population growth and no effect on S. avenae. However, AChE activity decreased in both R. padi and S. avenae treated by the LC₂₅ of pirimicarb. We demonstrated sublethal and transgenerational effects of pirimicarb in the two wheat aphid species; it hinted at the importance of considering sublethal effects (including hormesis) of pirimicarb for optimizing Integrated Pest Management (IPM) of wheat aphids.     

RAPD标记技术用于WHBE兔近交系培育中的遗传分析

目的探讨用随机引物扩增多态性DNA技术对大耳白黑眼兔近交系培育中的遗传监测作用。方法选用F4、F5、F6和F7代共70只WHBE兔的皮肤组织样品提取基因组DNA,用60个随机引物对基因组DNA进行PCR扩增,根据电泳结果筛选出其中25个多态性较高的引物进行RAPD-PCR分析,再利用Popgene 3.2统计软件对共检测到的584个扩增片段进行遗传分析,获得实验数据。结果①F4代扩增得到124条片段,F5代扩增得到150条片段,F6扩增得到152条片段,F7代扩增得到158条条带;其中F4代与F5代的共有条带数为105,F5代与F6代的共有条带数为119,F6代与F7代的共有条带数为125。②F4代与F5代的遗传相似度为0.7674,F5代与F6代的遗传相似度为0.7984,F6代与F7代的遗传相似度为0.8092。结论随着WHBE兔近交培育代数的增加,遗传相似度呈上升趋势,说明RAPD技术可以用于WHBE兔近交系培育的遗传检测。     

甲氧虫酰肼对棉铃虫生长发育的亚致死效应研究

以一个对甲氧虫酰肼具有18.5倍抗性的棉铃虫Helicoverpa armigera(Hübner)种群(R)和其同源对照种群(S)为对象,研究了甲氧虫酰肼对棉铃虫生长发育的亚致死效应。结果表明,甲氧虫酰肼亚致死剂量(LC25)处理R和S种群的3龄初幼虫,对S种群幼虫的生长抑制率(37.30%)显著大于R种群(21.20%)。与空白对照处理相比,致死剂量处理R和S种群后,均表现出生长发育延缓,蛹期延长,化蛹率、羽化率、卵孵化率降低,且对S种群的影响更明显。研究结果表明亚致死剂量的甲氧虫酰肼对棉铃虫存在一定的不利影响,但对甲氧虫酰肼具有一定抗性的棉铃虫种群能够减轻这种不利影响。     

Sublethal effects of imidacloprid on Bemisia tabaci (Hemiptera: Aleyrodidae) under laboratory conditions

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pests in tropical and subtropical agriculture and is a key pest in greenhouse production worldwide. Current management of B. tabaci relies upon frequent applications of insecticides. Insecticide use not only directly affects pest populations through acute toxicity but also has indirect (sublethal) effects on pest physiology or behavior. In this study, we described sublethal effects of imidacloprid on adult feeding, immature development, adult fecundity, and F1 development of B. tabaci. Honeydew excretion of adults feeding on leaves treated with LC20 and LC40 concentration was significantly lower than that on untreated leaf discs. Egg production of B. tabaci adults subject to LC20 and LC40 concentrations also was less than untreated individuals. Upon transfer to untreated leaves, honeydew excretion and egg production recovered well within 24 and 48 h, respectively. Exposure to LC20 and LC40 concentrations significantly affected developmental time of B. tabaci eggs and nymphs, whereas it did not affect adult molting rate. We did not find sublethal effects on longevity and fecundity of B. tabaci adults when exposed to LC90 and LC40 concentrations for 24 h, and on egg hatching rate, nymphal mortality, and molting rate of the subsequent F1 generation. Exposure to imidacloprid at LC40 concentration significantly decreased the number of females in the F1 generation. Imidacloprid negatively affects development and reproduction of exposed individuals, and sex ratio of subsequent (F1) generation of B. tabaci, which probably disrupts B. tabaci population dynamics, slows population increase, and reduces infestation levels. Therefore, it is necessary to consider potential impact from imidacloprid for integrated management of the pest.     

Effects of Serratia marcescens on the F1 generation of laboratory-reared Heliothis virescens (Lepidoptera: Noctuidae)

The effects of the bacterium Serratia marcescens (Bizio) was investigated on the F1 generation of laboratory-reared Heliothis virescens (F.). There was no difference in adult male or female longevity (i.e., parental generation) for individuals inoculated with S. marcescens as larvae (Serratia treatment) and those that were free of the bacterium (control treatment). However, the number of eggs laid and the prevalence of eclosion of eggs from Serratia treatment adults were reduced relative to control treatment adults. A very low number of F1 Serratia treatment eggs exhibited signs of infection, but a higher prevalence of mortality was observed for F1 larvae (n = 2,888) for the Serratia (3.5-4.6%) than for the control (1.1-1.5%) treatment. No S. marcescens was isolated from dead control larvae; whereas, 48 -54% of dead F1 larvae for the Serratia treatment were positive for the bacterium. However, there was no significant difference in larval weights between treatments. There were also no differences in either mortality or weight of F1 male pupae between treatments, but F1 female pupae were significantly smaller and prevalence of mortality was higher for the Serratia treatment. Serratia marcescens was not isolated from any of the control F1 pupae, but 6% of pupal cadavers for the Serratia treatment were positive for the bacterium. No S. marcescens was recovered from the meconia of any of the F1 adults (n = 2,600) regardless of treatment, and there were no differences in adult weights between treatments. Although sublethal effects of S. marcescens were detected, the impact and prevalence of the bacterium were tremendously reduced over the F1 generation in the absence of all but the most basic management strategies.