阿维菌素和哒螨灵亚致死剂量对土耳其斯坦叶螨实验种群生命表的影响

为了了解阿维菌素和哒螨灵对土耳其斯坦叶螨Tetranychus turkestani Ugarov et Nikolski实验种群的亚致死效应, 为新疆土耳其斯坦叶螨的综合防治提供理论依据, 我们在室内通过叶碟饲养的方法, 利用生命表技术研究了阿维菌素和哒螨灵亚致死剂量对土耳其斯坦叶螨实验种群成螨和卵的影响。结果表明: 阿维菌素和哒螨灵LC₂₀、LC₁₀剂量处理成螨后, 可使成螨的产卵量、平均寿命和卵孵化率显著降低; 卵期、幼螨期、若螨期和产卵前期明显延长, 而成螨期和雌螨寿命又明显低于对照; 对次代种群的影响表现在净生殖率(R₀)、 周限增长率(λ)降低、生存率和平均每雌日产卵率明显降低, 内禀增长率（r_m）由0.37降低至0.17～0.29, 平均世代历期(T)除阿维菌素LC₂₀处理时长于对照外, 其他处理均低于对照, 种群倍增时间(Dt)延长。两种药剂亚致死剂量处理卵后, 内禀增长率（r_m）由0.32降低至0.11～0.22, 净生殖率(R₀)降低, 平均世代历期(T)和周限增长率(λ)降低, 而种群加倍时间(Dt)增长; 幼螨期、若螨期和产卵前期明显长于对照, 成螨期和雌螨寿命显著低于对照; 生存率和平均每雌日产雌率明显降低。这些结果证明, 在亚致死剂量下, 阿维菌素和哒螨灵能够降低土耳其斯坦叶螨种群的发育速率, 这对土耳其斯坦叶螨的综合防治策略的制定有积极意义。     

山东省五个棉花产区绿盲蝽对药剂的敏感性检测（英文）

利用闪烁管药膜法测定了2009年山东省德州、滨州、梁山、曲阜和聊城5个棉花产区绿盲蝽Lygus lucorum Meyer-Dür对硫丹、马拉硫磷、毒死蜱、灭多威、丁硫克百威、吡虫啉、联苯菊酯和氟虫腈8种杀虫剂的敏感性,筛选出适合各地区的高效防治药剂。结果表明：5个地区绿盲蝽种群对马拉硫磷、毒死蜱、丁硫克百威、联苯菊酯和吡虫啉处于敏感性阶段。不同种群之间对灭多威、硫丹和氟虫腈的敏感性差异较大,其中聊城种群为最敏感种群,滨州种群对灭多威、 硫丹和氟虫腈的LC₅₀值分别为聊城种群的5.12,6.04和39.80倍;曲阜种群对灭多威、硫丹和氟虫腈的LC₅₀值分别为聊城种群的22.12,5.48和22.80倍。两种群对此3种药剂的敏感性下降,而其余种群仍处于较敏感阶段。8种药剂对绿盲蝽成虫的毒力按大小依次排序为：氟虫腈＞灭多威、联苯菊酯、硫丹＞马拉硫磷、毒死蜱＞丁硫克百威＞吡虫啉。2009年7-10月间德州夏津绿盲蝽种群对8种杀虫剂的敏感性变化极微。     

共生菌Cardinium对朱砂叶螨的生殖调控作用

为了了解共生菌Cardinium对朱砂叶螨Tetranychus cinnabarinus (Boisduval)的生殖调控作用,从检测到感染Cardinium的种群中选取山西运城和甘肃兰州2个感染率较高的种群作为实验材料,对Cardinium在寄主生殖调控方面的作用进行研究。通过人工培养100%感染Cardinium的种群和100%不感染的种群,并从中挑取不同感染类型的雌雄螨单独进行杂交实验,设立感染Cardinium(♀)×感染Cardinium(♂),感染Cardinium(♀)×不感染(♂),不感染(♀)×感染Cardinium(♂),不感染(♀)×不感染(♂) 4种杂交组合。结果发现,抗生素处理后不感染的雌螨和受感染雄螨的交配表现出了单向的胞质不亲和,而且2个种群表现出了2种类型：在山西种群不亲和的组合中,CI表现为卵孵化率显著降低,多数雌螨都产生出F₁雌螨后代,但是F₁代雌螨数量相对于其他3种组合明显减少; 而在甘肃种群不亲和的组合中则表现为卵全部孵化且幼螨100%存活,但全部为雄螨后代。2个种群中Cardinium的亲缘关系非常相近,而它们却能够在不同的地理种群中表现出不同的CI表型,这提示亲缘关系非常接近的品系也可以产生不同的表型。研究结果为深入揭示Cardinium的感染机制和生殖调控作用提供重要基础。     

Wolbachia感染对拟澳洲赤眼蜂寿命、生殖力和嗅觉反应的影响

研究了通过共享同一寄主卵,短管赤眼蜂Trichogramma pretiosum体内共生的Wolbachia被水平传递到拟澳洲赤眼蜂T. confusum体内后,Wolbachia对新宿主拟澳洲赤眼蜂的影响。结果表明： Wolbachia的侵染能使拟澳洲赤眼蜂进行不完全的产雌孤雌生殖,增加拟澳洲赤眼蜂子代雌性比例,但却导致了雌蜂寿命缩短和繁殖力降低的生理损失。Wolbachia感染的当代处女蜂及其建立的种群连续5代(F₁～F₅),其子代雌蜂百分率分别为79.17%、76.60%、68.66%、72.58%、68.15%和64.06%,基本上呈现出逐代降低的趋势,并越来越接近对照的63.85%。处女蜂及F₁～F₅代雌蜂的平均寿命分别为4.33、5.50、5.60、6.68、7.32和7.50天,而未感染交配雌蜂寿命为7.59 天;处女蜂及F₁～F₅代雌蜂平均产卵量分别为11.33、70.00、86.41、93.90、102.92和124.38粒/雌,除F₅代外,均显著低于未感染交配雌蜂的产卵量134.81粒/雌。用四臂嗅觉仪测定了Wolbachia新宿主拟澳洲赤眼蜂对寄主小菜蛾的嗅觉反应,结果表明Wolbachia的侵染具轻微干扰拟澳洲赤眼蜂嗅觉反应的负面影响。未感染Wolbachia的拟澳洲赤眼蜂及Wolbachia供体短管赤眼蜂对寄主小菜蛾具较强的嗅觉反应,其雌蜂在小菜蛾腹部鳞片正己烷提取液和小菜蛾卵表正己烷提取液处理区内滞留时间显著或极显著长于对照区。而感染Wolbachia的拟澳洲赤眼蜂F₂代和F₃代雌蜂,尽管在小菜蛾腹部鳞片正己烷提取液处理区内滞留时间比对照区长,但没有达到显著水平;其F₂代雌蜂在小菜蛾卵表正己烷提取液处理区内滞留时间与对照区相比,也没有达到显著水平。随Wolbachia在拟澳洲赤眼蜂种群中垂直感染代数的增加,拟澳洲赤眼蜂对寄主小菜蛾的嗅觉反应恢复正常,在Wolbachia感染后的 F₄～F₆代,雌蜂在两种提取液处理区内的滞留时间均显著或极显著长于对照区。     

茚虫威和六伏隆对小菜蛾卵、幼虫和成虫的药效（英文）

化学防治是世界各地防治小菜蛾Plutella xylostella (L.)的主要方法。选择对小菜蛾各发育阶段高效的杀虫剂有助于很好地控制这一害虫。本研究用浸叶法测定了茚虫威和六伏隆对小菜蛾卵、幼虫和成虫的毒性。茚虫威和六伏隆对小菜蛾卵的LC₅₀值分别为201.40 和 37.32 mg/L。茚虫威和六伏隆对3龄幼虫也有很好的毒性（茚虫威的LC₅₀ 为 4.82 mg/L; 六伏隆的LC₅₀ 为1.48 mg/L)。对成虫的毒性结果表明, 这两种杀虫剂对成虫均没有理想的毒性（茚虫威的LC₅₀ 为845.20 mg/L; 六伏隆的LC₅₀ 为3 438 mg/L)。根据计算的LC₅₀值, 六伏隆对小菜蛾卵和幼虫的毒性比茚虫威高, 但是茚虫威对成虫的毒性更高。     

感染稻水象甲的Wolbachia基因组中插入序列的鉴定与分析

共生细菌Wolbachia对宿主的生殖起多种调控作用。以往研究表明, Wolbachia基因组中广泛存在插入序列(insertion sequence, IS), 它们对宿主基因组的可塑性、 多样性和进化起重要作用。稻水象甲Lissorhoptrus oryzophilus Kuschel在东亚是一种外来水稻害虫, 在原产地北美营两性生殖, 而在所有入侵地均营孤雌生殖。本研究采用PCR法从河北唐海孤雌生殖型稻水象甲体内克隆获得了Wolbachia的2条IS序列, 即ISWosp4和ISWosp6; 从美国德克萨斯州两性生殖型稻水象甲成虫体内克隆获得了Wolbachia的2条IS序列, 即ISWosp3和ISWosp5。碱基序列比对显示: ISWosp3和ISWosp4属于IS3家族IS3组成员, ISWosp5为IS4家族IS231组成员, ISWosp6为IS5家族IS1031组成员。对这些IS的ORF结构、 所编码氨基酸序列的结构等进行了分析, 推测ISWosp5具有潜在转座活性。所得结果增进了我们对Wolbachia IS3, IS4和IS5家族插入序列的认识, 同时为今后从IS的角度探讨Wolbachia与稻水象甲生殖的关系奠定了基础。     

菲律宾实蝇生物学特性研究

菲律宾实蝇Bactrocera (Bactrocera) philippinensis (Drew & Hancock)是重要的检疫性有害生物, 严重危害芒果Mangifera indica L.、木瓜Carica papaya L.和菠萝蜜Artocarpus heterophyllus Lam.等水果。本文在室内实验条件下对菲律宾实蝇生物学特性进行了较为系统的研究。结果表明: 菲律宾实蝇在6~18 h羽化率达93.93%。成虫活动、寿命、交配和产卵与温度、光照密切相关。补充营养能显著延长成虫寿命。菲律宾实蝇生长、发育和繁殖的适宜温度为25~30℃。25℃和30℃时平均产卵量分别为627.35粒和652.57粒。发育起点温度和世代有效积温分别为14.31℃和450.43日·度。温度与发育历期呈显著的负相关（r=-0.9005）。本研究为菲律宾实蝇的检疫处理和田间防治技术研究提供了重要的基础资料。     

不同杀虫剂选育对家蝇抗药性水平及kdr基因频率的影响

采用杀虫剂（溴氰菊酯和甲基嘧啶磷）筛选及不接触药物自然衰退的方法,研究了家蝇Musca domestica氯氟氰菊酯高抗品系(Cyh-R)对杀虫剂的抗性变化,探讨蝇类抗药性治理的方法。用点滴法测定氯氟氰菊酯对不同家蝇品系的毒力,比较抗药性的变化,结合特异性等位基因PCR扩增（PASA）技术检测了不同家蝇品系的kdr基因频率,探讨kdr基因频率与抗性水平之间的关系。结果表明:甲基嘧啶磷筛选后,氯氟氰菊酯对第2~8代Cyh-R品系的LD₅₀呈递减趋势,从F₀的2.8434 μg/蝇降为F₈的0.4404 μg/蝇,但第8~18代Cyh-R品系的LD₅₀呈逐代递增趋势;溴氰菊酯筛选后,氯氟氰菊酯对Cyh-R品系第2~16代的LD₅₀呈上升趋势,从F₀的2.8434 μg/蝇升至F₁₆的24.3249 μg/蝇;表明了施用有机磷杀虫剂可降低其对氯氟氰菊酯的抗药性,而施用拟除虫菊酯药剂则有助于其对氯氟氰菊酯抗药性的增长;不使用任何杀虫剂也能降低其对氯氟氰菊酯的抗药性,但下降速率低于甲基嘧啶磷。PASA技术检测表明Cyh-R品系的kdr抗性基因频率为88.8%,不经过任何药剂筛选其kdr抗性基因频率下降程度最大,达到69.7%;甲基嘧啶磷筛选后其结果降为78.8%,而经溴氰菊酯筛选后kdr抗性基因频率则明显升高,达到98.9%。通过对kdr抗性基因频率和抗性水平进行相关和回归分析表明kdr抗性基因频率与家蝇对氯氟氰菊酯的LD₅₀呈对数关系,即LD₅₀值高的品系其kdr抗性基因频率相应的也较高。建议在家蝇防治中考虑轮换用药。     

两种室内生物测定方法评价杀虫剂对绿盲蝽的相对毒力

随着Bt棉在我国的广泛种植, 绿盲蝽Lygocoris lucorum Meyer-Dür的危害日益加重。化学防治作为棉田盲蝽综合治理的重要策略, 仍是其主要的防治手段。本研究主要用闪烁管药膜法和点滴法两种测定方法评价了传统杀虫剂、新型杀虫剂等30种杀虫剂对绿盲蝽成虫的急性触杀毒力, 其中多种杀虫剂是首次使用两种生测方法同时进行毒力测定。结果表明：有机氯类、有机磷类、氨基甲酸酯类和拟除虫菊酯类等传统杀虫剂对绿盲蝽成虫具有较高的触杀活性。8种对绿盲蝽成虫具有较高毒力的药剂, 其中5种为传统杀虫剂, 分别为马拉硫磷、毒死蜱、联苯菊酯、灭多威和硫丹。新型吡咯类杀虫剂对绿盲蝽表现出较高毒力, 以氟虫腈的毒力最高, 两种生测方法测定的LC₅₀分别为0.13 μg·mL^-1 和 0.15 μg·mL^-1。而昆虫生长调节剂、抗生素类及植物源杀虫剂对绿盲蝽成虫没有明显的触杀活性。     

棉铃虫细胞色素P450 CYP6B7基因的克隆与融合表达

细胞色素P450 CYP6B7被推测与棉铃虫Helicoverpa armigera对拟除虫菊酯类杀虫剂的抗性有关,但至今尚无CYP6B7参与杀虫剂代谢方面的直接证据。为揭示CYP6B7的代谢功能,作者以棉铃虫幼虫基因组DNA 为模板,以CYP6B7基因设计特异性引物,扩增出包含321 bp内含子的CYP6B7基因。用反向PCR的方法消除内含子,获得包含完整的CYP6B7基因的开放阅读框。将CYP6B7基因与pMAL-c2X载体连接,并转化E.coli TB1细胞,在IPTG诱导下,CYP6B7能与载体基因编码的麦芽糖结合蛋白（MBP）在大肠杆菌中融合表达,表达产物经直链淀粉（amylose） 柱亲和层析分离洗脱后,得到SDS-PAGE电泳纯的融合蛋白。     

Assessment of Potential Sublethal Effects of Various Insecticides on Key Biological Traits of The Tobacco Whitefly,Bemisia tabaci

The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects'' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of imidacloprid and bifenthrin may play an important role in the control of whitefly pests by increasing the toxicity persistence in treated crops.     

在玻璃表面上短时接触硅藻土和多杀菌素对四纹豆象的致死效应和亚致死效应（英文）

四纹豆象Callosobruchus maculatus (F.)是伊朗豇豆种子上的主要贮藏害虫。控制这一害虫时, 用生物杀虫剂比用常规杀虫剂更为合适。本研究评价了室内条件下在玻璃表面上硅藻土和多杀菌素对四纹豆象成虫的致死效应和亚致死效应。结果表明： 硅藻土处理24 h和48 h后, 对四纹豆象成虫的LC50 值分别为 1.47和0.2 g/m²; 多杀菌素处理24 h和48 h后, 对四纹豆象成虫的LC50 值分别为102.9 和68.8 mg ai/L, 说明两种化合物都对四纹豆象成虫具有较高的急性毒性。通过检测生物学参数, 研究了LC₂₀浓度的硅藻土和多杀菌素对四纹豆象的亚致死效应。LC₂₀浓度的硅藻土和多杀菌素使四纹豆象成虫的繁殖力分别比对照降低了71.5%和17.2%, 卵孵化率降低了57.5%和27.8%, 成虫寿命缩短了74.7%和17.1%。接触LC₂₀浓度的硅藻土和多杀菌素使这一害虫的蛹期分别比对照延长了4.8%和2.3%。亚致死效应研究表明, 硅藻土和多杀菌素对四纹豆象的生命参数均产生了负面影响。总之, 致死效应和亚致死效应综合显示, 硅藻土在防治四纹豆象上具有较大的潜力。     

苯甲酰基脲类杀虫剂对绿盲蝽的生物活性及亚致死影响

本文系统地比较了有代表性的4种苯甲酰基脲类杀虫剂对绿盲蝽Apolygus lucorum(Meyer-Dür)的生物活性和亚致死剂量对绿盲蝽生长发育及繁殖的影响。结果表明,苯甲酰基脲类杀虫剂对绿盲蝽各龄若虫均有较高的毒力,供试苯甲酰基脲类杀虫剂中,氟啶脲对绿盲蝽2龄若虫的毒力最高,其LC50为51.63 mg/L;氟铃脲对其3龄若虫毒力最高,其LC50为66.87 mg/L;杀铃脲对绿盲蝽4龄若虫毒力最高,其LC50为93.04 mg/L,3种药剂毒力均高于马拉硫磷。以4种苯甲酰基脲类杀虫剂LC30～40剂量处理绿盲蝽若虫后,对其存活若虫的生长发育和繁殖产生明显的后续影响。氟铃脲对试虫的影响最大,处理2龄若虫,表现为其若虫发育历期延长、成虫产卵量略有降低、成虫寿命降低;处理4龄若虫,羽化率降低、成虫产卵量、成虫寿命均降低。     

亚致死剂量杀虫剂对异色瓢虫繁殖力的影响

为协调害虫的化学防治与生物防治,测定了吡虫啉、鱼藤酮、氰戊菊酯、阿维菌素、抗蚜威和印楝素6种杀虫剂亚致死剂量对异色瓢虫成虫繁殖力的影响．结果表明,各处理异色瓢虫每雌每日产卵量为40～55粒,吡虫啉接触法和饲喂法预处理及鱼藤酮和印楝素饲喂预处理后,均显著低于对照．所有处理间每雌累积产卵量差异不显著．6种药剂2种方式处理异色瓢虫后,其所产卵的孵化率均低于对照,从卵发育至蛹期的累积存活率均显著降低．吡虫啉两种方式处理和氰戊菊酯接触处理,从卵至蛹期的总发育历期显著延长,鱼藤酮两种方式处理和氰戊菊酯、阿维菌素、抗蚜威、印楝素饲喂法处理的总发育历期明显比对照缩短,而鱼藤酮和阿维菌素接触处理的与对照差异不显著．药剂直接浸渍处理异色瓢虫卵后,各处理卵的孵化率均较对照降低．氰戊菊酯处理的l龄幼虫存活率也明显较对照低,2龄至蛹期的存活率也有所下降．鱼藤酮和氰戊菊酯处理的总发育历期显著延长．这些研究结果显示,低剂量的杀虫剂对异色瓢虫繁殖力的影响很复杂,药剂的类型、作用方式、毒性高低以及给药途径等均影响到试验结果．     

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.     

桔小实蝇实验种群对敌百虫、高效氯氰菊酯和阿维菌素的抗性增长规律

桔小实蝇Bactrocera doralis (Hendel)是华南地区水果蔬菜上重要害虫,近年来暴发成灾,造成巨大的经济损失。使用化学杀虫剂是防治该虫的重要方法。在长期、频繁接触杀虫剂条件下该虫的抗药性产生、发展规律等问题值得深入研究。本文采用LC₅₀、LC_80-90两种剂量汰选成虫、幼虫,研究了桔小实蝇对敌百虫、高效氯氰菊酯和阿维菌素3种药剂的抗性增长规律。通过不接触药剂继代饲养获得了对3种杀虫剂的敏感品系,建立了毒力回归方程,明确了毒力敏感基线LC₅₀分别为1.6024 mg/L,3.0964 mg/L和0.6074 mg/L。不同药剂种类、不同汰选方式时桔小实蝇的抗药性发展速度是不同的。以成虫死亡率50%左右作为选择压力,桔小实蝇对敌百虫的抗性发展最快,汰选至14代抗性增长至84.6倍;其次是高效氯氰菊酯,抗性增长至27.1倍;而对阿维菌素的抗性仅上升至7.7倍 。在成虫和幼虫80%～90%死亡率左右的选择压力下,桔小实蝇对高效氯氰菊酯的抗性发展最快,汰选14代后抗性增长至125.4倍; 其次是敌百虫,抗性增大至49.9倍;对阿维菌素抗性增长相对较缓慢,11代后为17.9倍。在成虫80%～90%死亡率左右的选择压力下,汰选14代、14代、11代后桔小实蝇对高效氯氰菊酯、敌百虫、阿维菌素分别增大至58.7倍、37.6倍、11.9倍。对成虫、幼虫均进行汰选桔小实蝇抗药性发展更快。建立了不同汰选方式时桔小实蝇实验种群汰选代数与对3种杀虫剂的抗性程度之间的关系方程,其中高效氯氰菊酯、敌百虫处理符合韦布尔曲线模型,阿维菌素处理符合幂曲线方程。     

Sublethal effects of selected insecticides on fecundity and wing dimorphism of green peach aphid (Hom., Aphididae)

Effects of sublethal concentrations (LC₂₅) of six insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on fecundity and wing dimorphism of the green peach aphid, Myzus persicae (Sulzer), were studied both under laboratory and greenhouse conditions. In the laboratory, aphid reproduction reduced by 44.29% and 54.01% when rotenone and abamectin treatments were applied at sublethal dose, respectively, and sublethal fenvalerate application resulted in markedly lower average reproduction per female per day compared with control. Reproductive duration of aphid treated with abamectin significantly decreased by 44.19%. But in the greenhouse, there were no evident differences in the aphid fecundity and reproductive duration between treatments and control. Life‐table parameters also demonstrated that the six insecticides at sublethal doses did not stimulate the aphid reproductive potential. In the laboratory, after being exposed to sublethal doses of imidacloprid and fenvalerate, the proportions of alate progeny in aphid progeny were significantly higher than that of the control. In the greenhouse, percentages of alate offspring from the mother aphids treated with imidacloprid, fenvalerate and abamectin increased pronouncedly compared with control. Mortality rates of offspring in the nymphal stages from adults treated with insecticides revealed no significant changes between laboratory and greenhouse. The developmental time in days of the offspring varied in all treatments. Mechanisms of insecticide‐induced resurgence are discussed.     

Acute and sublethal effects of neonicotinoids and pymetrozine on an important egg parasitoid,Trichogramma ostriniae (Hymenoptera: Trichogrammatidae)

Both neonicotinoids and pymetrozine are important insecticides and may have the potential to be used in combination with natural enemies in integrated pest management (IPM). However, to determine their compatibility with biological control, it is necessary to examine the side effects of these chemicals on natural enemies. We examined the acute and sublethal effects of four commonly used neonicotinoid insecticides, imidacloprid, dinotefuran, nitenpyram and thiamethoxam, and the pyridine azomethine, pymetrozine, on adults of Trichogramma ostriniae. By analysing acute toxicity and evaluating the safety quotient of these chemicals, we found that thiamethoxam and dinotefuran pose extremely high risks to T. ostriniae, imidacloprid and nitenpyram posed high risks, but pymetrozine was found to have a low risk. In terms of sublethal effects, longevities of female wasps were significantly shortened when they were exposed to residues of dinotefuran. Percentages of ovipositing females decreased significantly after exposure to pymetrozine, thiamethoxam and dinotefuran. Numbers of offspring per female were significantly lower when females were exposed to pymetrozine, dinotefuran or thiamethoxam, compared with control females. Percentages of offspring that emerged as adults were lower when parental females were exposed to either pymetrozine or imidacloprid. Based on the results of the sublethal concentration assay and the acute toxicity bioassay, nitenpyram would be safe for IPM programmes utilising T. ostriniae, and we suggest that T. ostriniae could be released safely after foliar applications of nitenpyram. However, foliar application of imidacloprid, thiamethoxam, dinotefuran or pymetrozine in an agro-ecosystem where T. ostriniae is a predominant biocontrol agent should be carefully evaluated.     

Contact and leaf residue activity of insecticides against the sweet Corn pest Euxesta stigmatias (Diptera: Otitidae)

Damage by Euxesta stigmatias Loew larvae to sweet corn renders the ears unmarketable. This report evaluates the efficacy of insecticides labeled for armyworm control in Florida sweet corn against E. stigmatias adults. Tests were performed in controlled settings by using direct contact and dried plant residues of esfenvalerate, cyfluthrin, lambda-cyhalothrin, chlorpyrifos, methyl parathion, methomyl, and thiodicarb. Direct application of all insecticides except thiodicarb quickly killed or caused incapacitating sublethal affects (uncoordinated movement, uncontrolled twitching, and hyperextension of mouthparts and ovipositor) to > 75% of the flies. Low rates (0.56 kg [AI]/ha) of chlorpyrifos and methyl parathion provided the most efficient control, killing 100 and 93%, respectively, within 2 h of direct contact. Low rates of pyrethroids induced low mortality but high sublethal effects that together immobilized nearly 100% of adults within 1 h of exposure. Mortality reached 95% within 2 h of direct contact in flies treated with high rates of pyrethroids. Methomyl killed as many as 94%, but required 24 h to reach this level after direct treatment. Residues on dipped leaves and field-treated plants of all tested insecticides except methyl parathion were less effective at killing adults compared with direct contact tests. Pyrethroid residues (particularly cyfluthrin) on field planted sweet corn induced significantly higher levels of sublethal effects (57-70%), and for a longer period of time, compared with materials in the other classes of chemistry.     

三种杀虫剂对褐飞虱海藻糖含量和海藻糖酶活性的影响

为了解农药处理导致褐飞虱Nilaparvata lugens (Stål）飞行能力增强的生理机制, 本文采用蒽酮法和酶促反应终止法, 研究了吡虫啉、 三唑磷和溴氰菊酯3种杀虫剂亚致死剂量对褐飞虱3龄、 5龄若虫及长、 短翅型雌雄成虫体内海藻糖含量和海藻糖酶活性的影响。结果表明： 杀虫剂处理的褐飞虱3龄若虫海藻糖含量和海藻糖酶活性与对照相比没有显著差异（P>0.05）。40 mg/L三唑磷处理的褐飞虱5龄若虫体内海藻糖含量显著低于对照（P<0.05）, 比对照降低了24%; 而20和40 mg/L三唑磷处理的褐飞虱5龄若虫海藻糖酶活性显著高于对照（P<0.05）, 分别比对照高出了100%和129%。10 mg/L吡虫啉, 20 和40 mg/L三唑磷以及3和6 mg/L溴氰菊酯处理的褐飞虱短翅雌成虫和雄成虫体内海藻糖含量显著低于对照（P<0.05）, 雌成虫体内海藻糖含量比对照分别降低了36%, 53%, 67%, 58%和69%, 雄成虫体内海藻糖含量比对照分别降低了59%, 71%, 65%, 70%和77%; 而40 mg/L三唑磷以及3和6 mg/L溴氰菊酯处理的褐飞虱短翅型雌成虫和雄成虫体内海藻糖酶活性显著高于对照（P<0.05）, 雌成虫体内海藻糖酶活性比对照分别高出了124%, 100%和88%, 雄成虫体内海藻糖酶活性比对照分别高出了146%, 132%和118%。10 mg/L吡虫啉, 40 mg/L三唑磷和3 mg/L溴氰菊酯处理的褐飞虱长翅型雌成虫和雄成虫海藻糖含量显著低于对照（P<0.05）, 雌成虫海藻糖含量比对照分别降低了44%, 34%和37%, 雄成虫体内海藻糖含量比对照降低了48%, 54%和43%; 而5和10 mg/L吡虫啉处理的长翅型雌成虫和雄成虫海藻糖酶活性显著高于对照（P<0.05）, 雌成虫体内海藻糖酶活性比对照分别高出了317%和300%, 雄成虫体内海藻糖酶活性比对照分别高出了170%和97%。这些结果说明这3种杀虫剂亚致死剂量处理可以增强褐飞虱体内海藻糖酶活性, 并导致海藻糖含量下降。本研究结果对深入阐明农药诱导褐飞虱再猖獗及杀虫剂处理增强其飞行能力的生理机制具有一定的科学价值。