Genetic basis of sex pheromone blend difference between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

The two closely related moth species, Helicoverpa armigera and H. assulta, are sympatric in China. Both species use a mixture of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as their sex pheromones but in widely different ratios. Hybridization and backcrossing experiments between H. armigera and H. assulta were conducted and sex pheromone compositions of the parent species, their F(1) hybrids and backcrosses were compared to study the genetic basis of the production of their sex pheromone blend composition. Results show that the difference in sex pheromone blend ratios of these Helicoverpa species is mainly controlled by an autosomal locus with two alleles, with the allele from H. armigera being almost completely dominant over that derived from H. assulta.     

Variation in susceptibility of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) in Australia to two Bacillus thuringiensis toxins

Intra-specific variation in susceptibility of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) in Australia to the Cry1Ac and Cry2Ab delta-endotoxins from Bacillus thuringiensis (Berliner) (Bt) was determined to establish a baseline for monitoring changes that might occur with the use of Bt cotton. Strains of H. armigera and H. punctigera were established from populations collected primarily from commercial farms throughout the Australian cotton belts. Strains were evaluated for susceptibility using two bioassay methods (surface treatment and diet incorporation) by measuring the dose response for mortality (LC50) and growth inhibition (IC50). The variation in LC50 among H. armigera (n=17 strains) and H. punctigera (n=12 strains) in response to Cry1Ac was 4.6- and 3.2-fold, respectively. The variation in LC50 among H. armigera (n=19 strains) and H. punctigera (n=12 strains) to Cry2Ab was 6.6- and 3.5-fold, respectively. The range of Cry1Ac induced growth inhibition from the 3rd to 4th instar in H. armigera (n=15 strains) was 3.6-fold and in H. punctigera (n=13 strains) was 2.6-fold, while the range of Cry2Ab induced growth inhibition from neonate to 3rd instar in H. armigera (n=13 strains) was 4.3-fold and in H. punctigera (n=12 strains) was 6.1-fold. Variation in susceptibility was also evaluated for two age classes (neonates and 3rd instars) in laboratory strains of H. armigera and H. punctigera. Neonates of H. punctigera had the same or higher sensitivity to Bt than 3rd instars. Neonates of H. armigera were more sensitive to Cry2Ab than 3rd instars, while being less sensitive to Cry1Ac than 3rd instars. Differences in the two methods of bioassay used affected relative sensitivity of species to Bt toxins, highlighting the need to standardize bioassay protocols.     

Modeling Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) damages on cotton

We studied and modeled damage caused by Helicoverpa armigera larvae on cotton with the aim of developing a coupled crop pest model. Two damage components were studied: the voracity (quantity of fresh matter and number of organs consumed) and feeding preferences (type of organ infested). The laboratory no-choice study of voracity on excised squares and bolls revealed that an H. armigera larva consumes 2,856 mg of fresh matter throughout its larval life, with the sixth instar consuming 86% of this quantity. This consumption rate corresponded to 23.6 squares, or 7.8 bolls. We developed equations to predict the quantity of fresh matter uptake from an individual plant organ, according to the organ mass and the larval instar. The field study of feeding preference confirmed previous findings that larvae prefer squares to bolls, with this preference decreasing as the larval age increases. However, no significant relationship was noted between the age of larvae and the size of infested organs within each organ class (square or boll). We developed a logistic model to predict the probability of a larva infesting a boll rather than a square. According to this model, the relative organ availability in the field and the larval instar were found to be significant factors.     

烟青虫(Helicoverpa assulta Guenée)信息素的结构鉴定及田间试验(英语)

北京地区的烟青虫(Helicover Pa asslta Cucn(?)e)的性信息素腺体提取物经毛细管柱气相色谱分析及GC MS分析,鉴定了6种组分.这6种组分为:十六醛(16:Ald)、顺 9—十六烯醛(Z9—16:Ald)、顺11—十六烯醛(Zll 16:Ald)、顺9—十六烯醇(Z9-16:OH)、顺11—十六烯醇(Zll-16:OH)、顺9—十六烯基乙酸酯(Z9 16:OAc),比例为10.9:58.7:3.9:14.7:1.1:10.7.田间试验表明,只有16:Ald、Z9 16:Ald和Zll 16:Ald(比例为15.3:79.2:5.5)组成的三组分诱芯和Z9—16:Ald和Zll—16:Ald(比例为93.4:6.6)组成的两组分诱芯对于雄蛾有强烈的引诱活性.在3种醛为组分的诱芯中加入Z9 16:OH明显地降低引诱活性.     

莱氏野村菌(Nomuraea rileyi)对棉铃虫(Helicoverpa armigera)幼虫的致病机理研究

本文利用荧光显微镜、光学显微镜及组织切片技术进行了莱氏野村菌对棉铃虫幼虫的致病过程及机理的研究。两个莱氏野村菌菌株ＥＦＤ44及ＥＦＤ38不同浓度及配方的分生孢子 ,在棉铃虫幼虫体皮上 2ｈ后开始发芽。两个菌株的分生孢子发芽方式不尽相同。真菌在侵入昆虫表皮体内前 ,菌株ＥＦＤ44及ＥＦＤ38的芽管发生了不同程度的分化。ＥＦＤ38芽管有几种分化形式 ,包括形成驸胞器结构、主芽管从孢子多处萌发、主芽管有或多或少的分枝、主芽管或分枝芽管形成楔型状等。处理后约 6ｈ ,真菌菌丝或芽管开始侵入昆虫外体皮 ,但真正成功地侵入外体皮并…     

不同光波及光强度下棉铃虫(Helicoverpa armigera)成虫的行为反应

运用室内行为实验方法研究了不同波长单色光和白光刺激的棉铃虫[Helicoverpa armigera (Hübner)]成虫趋光、避光反应及其与光强度之间的相互关系.结果显示:(1)一定时间暗适应的棉铃虫蛾对单色光和白光刺激均具有趋光行为反应,依其趋光反应率大小,其光谱反应曲线在340-605nm波谱范围内,表现为大小较复杂的几个峰,其中两个峰分别在蓝光区483nm、紫外340nm,另在近紫外的400nm、绿黄光区的538nm有峰.(2)一定光强度范围内,棉铃虫蛾的趋光反应率随单色光和白光光强度的增强而增大,至一定光强度时增加变缓,呈现近似S型曲线式样.(3)性别、日龄对棉铃虫蛾的光谱、光强度反应曲线均有一定影响,雌性较雄性的趋光反应率和可适应的光强度高,1、3、5日龄蛾中以3日龄的趋光反应率和可适应的光强度高.(4)棉铃虫蛾的趋光、避光反应行为具有相似的波长及光强度选择机制.     

不同光波及光强度下棉铃虫(Helicoverpa armigera)成虫的行为反应

运用室内行为实验方法研究了不同波长单色光和白光刺激刺激的棉铃虫「Ｈｅｌｉｃｏｖｅｒｐａ ａｒｍｉｇｅｒａ（Ｈｕｂｎｅｒ）」成虫趋光、避光反应及其与光强度之间的相互关系,结果显示：（１）一定时间暗适应的棉铃虫蛾对单光和白光刺激均具有趋光行为反应,依其趋光反应率大小,其光谱反应曲线在３４０－６０５ｎｍ波谱范围内,表现为大小较复杂上峰,其中两个峰分别在蓝光区４８３ｎｍ、紫外３４０ｎｍ,另外近紫外的４０ｎ     

Electrophysiological responses of female Helicoverpa armigera (Hübner) (Lepidoptera; Noctuidae) to synthetic host odours

Studies were conducted to investigate the electroantennographic (EAG) responses of adult female Helicoverpa armigera to a range of known and putative kairomone components. The studies show that at a given dose the EAG responses elicited by a series of straight-chain aliphatic primary alcohols were not dependent on volatility since butan-1-ol and pentan-1-ol elicited EAG responses that were significantly smaller than those elicited by hexan-1-ol. The amplitudes of responses to hexan-1-ol were found to be dose dependent with a dose of 10(-1) μmol at source in a non-volatile solvent eliciting the largest response. Similarly, changes in functionality in a range of C(6) straight-chain aliphatic compounds significantly changed the amplitude of response elicited, with aldehydes eliciting smaller responses than the related primary alcohols and saturated compounds eliciting higher responses than related unsaturated compounds. Of the range of nine host plant-produced terpenoids tested, ocimene and beta-phellandrene elicited the highest responses and of the six aromatic compounds tested phenylacetaldehyde and benzaldehyde elicited the largest responses, at the doses tested. The significance of these findings for analysis of floral odours by gas chromatography linked to electroantennography as a means of identifying kairomone components attractive to H. armigera are discussed.     

Characterization of three pheromone-binding proteins (PBPs) of Helicoverpa armigera (Hübner) and their binding properties

Three pheromone-binding proteins of Helicoverpa armigera were cloned and expressed in Escherichia coli. In order to characterize their physiological properties, ligand-binding experiments were performed using five biologically relevant substances including sex pheromones and interspecific signals. The results showed that one of the pheromone-binding proteins, HarmPBP1, binds strongly to each of the two principal pheromone components of H. armigera, (Z)-11-tetradecenal and (Z)-9-hexadecenal, but not to the interspecific signal (Z)-9-tetracecenal. The two remaining pheromone-binding proteins, HarmPBP2 and HarmPBP3, showed only weak affinities with the ligands tested. The 3-D structure of HarmPBP1 was predicted and the docking experiments indicate that the key binding site of (Z)-9-hexadecenal to HarmPBP1 includes Thr112, Lys111, and Phe119 whereas that of (Z)-11-tetradecenal includes Ser9, Trp37, Phe36, and Phe119.     

Karyomorphological effects of two new oil formulations on Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

The cotton bollworm Helicoverpa armigera is a serious pest of many economically important crops. Since this pest has become resistant to the conventional synthetic insecticides, newer compounds and formulations are being developed against this insect pest. Many natural compounds isolated from the plants were tested against this pest. Among them Hyptis suaveolens and Melochia corchorifolia showed insecticidal properties against H. arnigera. Based on bioefficacy studies, caryophyllene and β-sitosterol were isolated from H. suaveolens and M. corchorifolia respectively. The isolated natural compounds were further developed as formulations in various combinations with neem (Azadirachta indica) and karanj (Pongamia pinnata) oils. The present study indicated that the formulations influenced the karyomorphology of H. armigera.     

Mechanisms of monocrotophos resistance in cotton bollworm,Helicoverpa armigera (Hübner)

Insensitive acetylcholinesterase was identified as a resistance mechanism by comparing biochemical analysis with a laboratory selected monocrotophos resistant cotton bollworm (RR: 200) and the susceptible strain. The cDNA encoding AChE was cloned by the method of RACE (rapid amplification of cDNA ends). The complete AChE gene deduced from the cDNA consisted of a putative signal peptide of 32 amino acid residues, a mature protein of 615 residues, 5' untranslated regions (UTR) of 315 bp and 3' UTR of 324 bp. The coding sequence had a high degree of homology to the AChE from other insect species reported in the GenBank. After comparing analysis of the entire AChE gene sequence from 5 resistant and 6 susceptible cotton bollworm individuals, nine mutations were identified. One of them, the Ala/Thr mutation, is likely to be responsible for the AChE insensitivity to monocrotophos.     

Ovicidal activity of Couroupita guianensis (Aubl.) against cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

There is a great demand for food with increasing population of the world. Many chemical fertilisers and pesticides are used to increase crop productivity. Over use of pesticides and fertilisers has affected the environment and non-target organisms severely; minor pests have become major destructive pests. Hence, eco-friendly approaches are needed. The present study reports the effect of hexane, chloroform and ethyl acetate extract of Couroupita guianensis on the eggs of Helicoverpa armigera. All the extracts showed ovicidal activity, and among them hexane extract showed 64.28% ovicidal activity with LC₅₀ value of 2.62% and regression of (R ²) 83.5%. All the original data showed normality and homogeneity. The active hexane extract was fractionated; finally, eight fractions were obtained and studied at different concentrations. Among the fractions, fraction 8 showed 75% ovicidal activity with R ² of 90%. It showed LC₅₀ value of 322.94?ppm with χ ² value at 0.5%. C. guianensis could be used in pest management programme.     

棉田与玉米田棉铃虫(Helicoverpa armigera Hübner)种群动态特征的比较

1998年在江苏丰县系统调查了棉田和玉米田中第三、四代棉铃虫的种群动态,用生命表方法比较了两种寄主田内棉铃虫种群的发育速率和存活率.结果表明,棉铃虫卵峰期至4龄幼虫高峰期的历期在玉米田要比棉田快4d,并以产卵于玉米抽雄扬花期的发育最快.两类寄主田内平均存活率无显著差异,但产卵于玉米抽雄扬花期时,其卵至6龄幼虫的存活率比产在其它阶段玉米上的存活率高.在江苏棉区目前的作物布局和耕作制度下,玉米田第三代棉铃虫是棉田第四代棉铃虫的重要虫源.     

Structure and ultrastructure of the silk glands and spinneret of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

This study provides comprehensive documentation of silk production in the pest moth Helicoverpa armigera from gland secretion to extrusion of silk thread. The structure of the silk glands, accessory structures and extrusion apparatus are reported. The general schema of the paired silk glands follows that found for Lepidoptera. Morphology of the duct, silk press, muscle attachments and spigot are presented as a three-dimensional reconstruction and the cuticular crescent-shaped profile of the silk press is demonstrated in both open and closed forms with attendant muscle blocks, allowing advances in our knowledge of how the silk press functions to regulate the extrusion of silk. Growth of the spigot across instars is documented showing a distinctive developmental pattern for this extrusion device. Its shape and structure are related to use and load-bearing activity.     

棉铃虫(Helicoverpa armigera)FK506结合蛋白基因的克隆、表达与纯化

为了深入了解FK506结合蛋白基因的作用和探索调控棉铃虫CYP6B6的表达机制,基于单酵母杂杂交结果采用RT-PCR的方法从棉铃虫的中肠cDNA中扩增得到了FK506结合蛋白基因,将测序正确的目的片段克隆至原核表达载体pET32a中,在大肠杆菌BL21中用异丙基-β-D-硫代半乳糖(IPTG)诱导表达,通过镍柱离子亲和层析纯化目的蛋白。用SDS-PAGE检测目的蛋白的表达和纯化结果,并用Western blotting进行验证。结果表明,克隆得到的目的基因大小为327 bp,编码108个氨基酸残基,预测蛋白质分子量和等电点分别是11.78 kD和7.87。氨基酸序列分析表明该序列具有完整的开放阅读框,且没有信号肽。重组质粒pET32a-FKBP在大肠杆菌BL21中获得表达,主要以可溶性形式存在,经亲和层析柱纯化获得目的蛋白,Western blotting检测发现纯化的目的蛋白大小正确且纯度高。     

土壤特性对棉铃虫(Helicoverpa armigera Hübner)发生的影响及发生程度分区

统计分析表明,土壤的多种理化性质与棉铃虫的发生程度间存在着密切的关系,其中起主要作用的是土壤容重、砂粒含量和粘粒含量3个因子,其直接通径系数依次为-0.6521、0.6735和0.3456.这些因子使土壤表现出不同的粘性,决定了土壤的透气性、持水量和板结程度等,从而影响到棉铃虫幼虫人土后蛹的存活率.用上述3个因子进行聚类分析,可将通州市划分为3个棉铃虫发生区,各区域在测报和防治上应进行区别对待.     

光因子对棉铃虫(Helicoverpa armigera)雌蛾性信息素产生及其求偶行为的影响

分为3部分第1部分为光因子对棉铃虫雌蛾求偶行为的影响;第2部分为光因子对棉铃虫雌蛾性信息素(Z-11-16Ald)含量的影响;第3部分为光因子对棉铃虫雌蛾脑因子活性的影响。研究结果表明用非正常光周期、间隔光照、不同光质处理棉铃虫雌蛾后,求偶峰值下降,求偶节律混乱,性信息素含量下降,脑因子活性受到抑制。主要研究目的是探讨一种不使用或少使用农药的新型生态防治方法。     

Antifeedant activity of numb and salty taste compounds against the larvae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Helicoverpa armigera, an important polyphagous insect pest in agriculture, attacks more than 200 plant species of more than 30 families. Our previous study showed that the choice feeding percentages of H. armigera larvae to tobacco leaf discs treated with sweet, bitter, and hot taste substances were higher than the control leaf discs, while numb and salty substances could significantly inhibit their feeding. To quantitatively determine the synergistic effect of numb and salty substances, in this paper, the antifeeding activities of numb and salty substances and their mixtures blended in different doses or volume ratios were assayed on H. armigera larvae. The first bioassay was designed to elucidate the relative feeding preference of the larvae to the leaves from several common host species, each paired with tobacco leaf discs, and the result indicated that the most preferred host leaf by the larvae was tobacco leaf, followed by cotton and peanut leaves, suggesting that tobacco leaf was the most suitable matrix for the antifeeding bioassay, and the larval consumption of maize, pepper, or tomato leaves were significantly lower than that of tobacco leaf. The second bioassay was to test the choice feeding response of H. armigera larvae to tobacco leaf discs treated with Zanthoxylum bungeanum extracts obtained with different solvents, and the result showed that the antifeeding activity of the alcohol extracts was the strongest (93.38%), and the leaf consumption in the treatment and the control showed extremely significant difference (t = 4.23, t_0.01 = 3.25, P = 0.0022), followed by the dichloromethane extracts (47.64%), while the other three solvents (water, acetone, and n-hexane) could not extract the active antifeeding components from Z. bungeanum. The larval consumption of tobacco leaf discs treated with the alcohol extracts of Z. bungeanum and NaCl solution were significantly less than their corresponding controls. The mean larval consumption of the treated leaf discs decreased with ever-increasing dosage, and the consumption of tobacco leaf discs coated with different doses of alcohol extracts of Z. bungeanum or NaCl solution showed extremely significant difference (F_{alcohol extract of Z. bungeanum} = 3.88, F_0.01 = 3.58, P = 0.0064; F_{NaCl solution} = 54.29, F_0.01 = 3.58, P = 0.0000), with maximum antifeeding effects at a dosage of 30 μL per 1.5 cm ID leaf disc. We further tested the larval consumption of tobacco leaf discs treated with alcohol extracts of Z. bungeanum in saturated NaCl solution mixed in different volume ratios, and the result showed that the choice antifeeding percentages of the treatments with 15 μL or more Z. bungeanum alcohol extracts were higher than 90%, among which the mixture with 25:15 volume ratio of Z. bungeanum alcohol extracts and saturated NaCl solution exhibited the strongest antifeeding activity, and the mean consumed leaf area of tobacco leaf discs coated with this blend was only 0.10 mm². In the further test on feeding dose-response of the 25:15 mixture, the mean leaf consumption decreased linearly with ever-increasing dosage, with a regression equation y = ?3.9356x + 120.78(R² = 0.9998), and the 30 μL dose could completely inhibit H. armigera feeding.     

河北省棉铃虫(Helicoverpa armigera Hübner)种群数量的气象综合预报方法的研究

为了客观地反映棉铃虫种群数量变化与气候背景的关系规律,创建了棉铃虫气象多时段综合因子的因子组建方法;建立了贡献度权重修正的气象距离指标方法和模型;匹配以传统的多元回归模型,进行棉铃虫种群数量的气象监测和预报;将其自身生物潜能和气象条件影响相结合,建立了棉铃虫灾害的生物气象定量综合预报模型.在棉铃虫发生的气象条件评价和发生程度预测预报应用中,趋势准确率达到93%.