The Role of Formulation Additives in Increasing the Potency of Cydia pomonella Granulovirus for Codling Moth Larvae,in Laboratory and Field Experiments

Studies were undertaken to improve the biological efficacy of the granulovirus (CpGV) of the codling moth, Cydia pomonella , by evaluating the performance of some formulation additives that might improve virus persistence and/or virus uptake by first instar larvae. Laboratory studies, using a leaf disc bioassay, demonstrated that 15% cane molasses incorporated within a formulation of purified CpGV dramatically reduced the median lethal exposure time (LET 50 ) to CpGV for neonate larvae at a CpGV dosage rate of 10 7 occlusion bodies (OBs) ml -1 . Screening of a range of other compounds showed that sucrose, fructose and sorbitol (at 10% concentrations) and extracts of apple flesh and skin also gave significant reductions in the LET 50 of CpGV formulations containing these ingredients. Pectin, malic acid and &#102 -farnesene did not significantly reduce the LET 50 . In a field trial, molasses included at 15% (v/v) in a CpGV formulation, containing a dosage rate of 10 12 OBs ha -1 , gave as good control of codling moth damage as virus formulations containing the 'sticker' 0.2% skimmed milk at higher dosage rates of 10 13 and 10 14 OBs ha -1 . Studies of CpGV persistence on foliage revealed no significant improvement of virus persistence on apple foliage using 10% or 15% molasses formulations. A second field trial demonstrated that 10% molasses, 10% sorbitol or 0.08% &#102 -farnesene significantly reduced codling moth deep damage to fruit when these ingredients were added to formulations of pure CpGV. Substantial sooty-mould growth ( Cladosporium spp.) was observed on apple foliage treated with formulations containing molasses, indicating that this formulation additive has secondary consequences that would need to be taken into account if molasses was to be used in commercial CpGV formulations. Nonetheless, these studies clearly demonstrate that major biological improvements in CpGV performance can be achieved by the incorporation of formulation additives, including molasses and several other compounds, that probably function as attractants and/or feeding stimulants for codling moth larvae.     

Hickory shuckworm Cydia caryana: electroantennogram and flight tunnel studies of potential sex pheromone components

Electroantennogram (EAG) measurement of male Cydia caryana moth antennal olfactory response to monounsaturated 12 and 14 carbon alcohols and acetates indicated that the (E)-8-, (E)-10- conjugated double bond system of a dodecadien-1-ol acetate is a critical chemical structural component of the C. caryana sex pheromone. Additionally, EAG measurements implicated (E)-8-dodecen-1-ol acetate, (Z)-8-dodecen-1-ol acetate, (Z)-9-dodecen-1-ol acetate and (Z)-12-tetradecen-1-ol as potential minor pheromonal components. An EAG dosage-response study suggested that there were at least two heterologous populations of pheromone acceptors. Behavioral analysis of male moth response in a flight tunnel to compounds which evoked the stronger EAG responses suggested that (E,E)-8,10-dodecadien-1-ol acetate and (Z)-9-dodecen-1-ol acetate resemble or are C. caryana sex pheromonal components, while (Z)-8-dodecen-1-ol acetate and (E)-10-dodecen-1-ol acetate are either parapheromones or are minor pheromone components. Behavioral significance of (Z)-12-tetradecen-1-ol was difficult to interpret in the flight tunnel.

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Résumé Les réponses olfactives antennaires de Cydia caryana, mesurées par électroantennogrammes (EAG), aux alcools et acétates à carbones monounsaturés en positions 12 et 14, ont montré que le système conjugué de double liaison, (E)-8-, (E)-10- du dodecadien-1-ol acétate constitue un composé chimique strutural critique de la phéromone sexuelle de C. caryana.De plus, les acétates: (E)-8-dodecen-1-ol,(Z)-8-dodecen-1-ol,(Z)-9-dodecen-1-ol, et le (Z)-12-tetradecen-1-ol, se sont révélés en AEG comme des composés secondaires de la phéromone. L'étude par AEG de la relation dose-réponse a conduit à l'hypothèse de deux catégories de populations de récepteurs de phéromones. L'analyse comportementale des résponses des papillons mâles dans le tunnel de vol aux composés qui ont provoqués les plus forts AEG, on fait estimer que les acétates (E,E)-8,10-dodécadien-1-ol et (Z)-9-dodecen-1-ol ressemblent (ou sont) les constituants de la phéromone sexuelle de C. caryana; tandis que les (Z)-8-dodecen-1-ol et (E)-10-dodecen-1-ol sont, soit des paraphéromones, soit des constituants mineurs de la phéromone.La signification biologique du (Z)-12-tétradécen-1-ol a été difficile à interprêter avec les expériences en tunnel de vol.

     

苹果蠹蛾性信息素的研究和应用进展

苹果蠹蛾Cydia pomonella (L.)是我国重要的检疫害虫, 在我国仅分布于新疆和甘肃以西局部地区, 但一直保持向我国东部扩张的趋势。在国际上, 利用性信息素监测和迷向防治苹果蠹蛾已经成为一种切实可行并广泛应用的害虫管理技术。本文综述了苹果蠹蛾性信息素的成分鉴定、人工合成和应用情况的研究进展, 指出了目前存在的问题和应用前景, 以期为我国苹果蠹蛾的防控策略的研究和应用提供参考。     

苹果蠹蛾体内wolbachia wsp基因克隆与序列分析

【目的】对苹果蠹蛾Cydia pomonella L.体内共生菌Wolbachia进行分子生物学鉴定,确定该虫体内Wolbachia的进化位置,为进一步探讨Wolbachia对其生殖作用的调控机制提供理论依据。【方法】应用Wolbachia的wsp基因特异引物,通过PCR扩增法检测了苹果蠹蛾10个地理种群(新疆伊犁、吐鲁番、和田、石河子、奎屯、哈密、库尔勒、阿拉尔、喀什、和甘肃张掖)感染Wolbachia的状况,并对阿拉尔种群体内的Wolbachia的wsp基因进行测序和序列分析。【结果】苹果蠹蛾10个地理种群全部感染了tWolbachia,利用wsp基因的特异性引物从阿拉尔种群体内扩增出了617 bp的Wolbachia的wsp基因片段(GenBank登录号为KC832324),系统发育分析结果表明,苹果蠹蛾体内感染的Wolbachia属于A群Dor亚群,与锤角细蜂亲缘关系较近。【结论】苹果蠹蛾体内普遍感染了Wolbachia,属于A群Dor亚群。     

Investigating the horizontal transmission of the Cydia pomonella granulovirus (CpGV) in a model system

Repeated applications of Cydia pomonella granulovirus (CpGV) can effectively control the codling moth (CM) in apple orchards. However, it is still unknown whether horizontal transmission of the virus from infected to uninfected larvae contributes to the efficacy of the virus insecticide. Horizontal transmission of CpGV was assayed using detached apples. In experiments using artificially applied virus dots on the apple’s surface or infected CM larvae as virus inoculum, it was found that the likelihood of infection of healthy CM larvae relied mainly on the larval behavior. The amount of virus inoculum, either applied artificially or produced by the infected larvae, impacted the infection rate only to a small degree. In the experiments, CM larvae exhibited a strong preference in entry sites, increasing the chance for horizontal transmission. Depending on the experimental design, horizontal transmission rates of about 40% were observed in laboratory assays.     

Effects of dose and attractant on interactions between pheromone traps for the pea moth, Cydia nigricana

The effects of different doses of two attractants on the interactions between pheromone traps for the pea moth, Cydia nigricana (F.) were investigated. In lines of three traps along the wind, each containing 10³ g (E)-10-dodecen-1-yl acetate (E10-12: Ac), interactions were evident at spacings of 15 m and 50 m; the centre trap catch was suppressed (cf. an isolated trap) but, unlike interacting traps containing 10² g (E,E)-8, 10-dodecadien-1-yl acetate (E, E8, 10–12: Ac), the upwind trap did not catch more moths than the other traps.Changing the dose of E10-12: Ac in lines of traps with a spacing of 50 m did not affect the profile of catches, but reducing the dose of E, E8, 10–12: Ac to 1 g per trap resulted in a profile similar to that obtained with all doses of E10-12: Ac.The efficiency with which traps caught moths approaching within 1 m was affected by the attractant rather than the dose. Traps containing E, E8, 10–12: Ac were almost twice as efficient as those containing E10-12: Ac, suggesting that the former is a better close-range attractant.

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Zusammenfassung Die Wirkung verschiedener Mengen zweier Attraktivstoffe auf die gegenseitige Beeinflussung von Pheromonfallen für den Erbsenwickler, Cydia nigricana F., wurde untersucht. Drei Fallen mit je 10³ g des Pheromonanalogs (E)-10-dodecen-1-yl Acetat (E10-12: Ac), wurden in einer Reihe in der Hauptwindrichtung aufgehängt. Bei Fallenabständen von 15 m und 50 m war die gegenseitige Beeinflussung offensichtlich. Im vergleich mit isolierten Fallen wurde der Fang der zentralen Falle reduziert. Die Aufwindfalle fing nicht mehr als die andern Fallen und zwar im Gegensatz zu Versuchen, in denen die Fallen je 10² g des natürlichen Pheromons (E,E) 8, 10-dodecadien-1-yl Acetat (E, E8, 10–12: Ac) enthielten.Wenn die Menge von E10-12: Ac in Fallenreihen mit 50 m Abstand geändert wurde (z.B. 10⁴ g), wurde das Fangprofil nicht geändert. Wurde die Menge von E, E8, 10–12: Ac auf 1 g pro Falle vermindert, ergab sich ein Profil, das allen Kombinationen von E10-12: Ac entsprach.Die Fängigkeit der Fallen im Nahbereich von 1 m wurde mehr durch den Lockstoff als durch die Menge beeinflusst. Fallen mit E, E8, 10–12: Ac waren fast zweimal fängiger als Fallen mit E10-12: Ac (37% und 22%). Demnach scheint die erste Substanz der bessere Nahdistanzlockstoff zu sein.

     

The susceptibility of the pea moth, Cydia nigricana, to infection by the granulosis virus of the codling moth, Cydia pomonella

Laboratory studies demonstrated that neonate larvae of the pea moth, Cydia nigricana, are susceptible to infection with a granulosis virus (CpGV) isolated from the codling moth, Cydia pomonella. Comparative LC₅₀ values for C. nigricana and C. pomonella are 1.90 × 10⁵ and 1.54 × 10⁴ capsules/ml of diet, respectively. The virus extracted from CpGV-infected pea moth larvae is serologically related, and probably identical, to CpGV.     

Flight tunnel response of codling moth Cydia pomonella to blends of codlemone,codlemone antagonists and pear ester

Upwind orientation flights of codling moth males Cydia pomonella L. to a single source of sex pheromone (E,E)‐8,10‐dodecadienol (codlemone) are significantly reduced when blending it with pheromone antagonists, either with codlemone acetate, (E,E)‐8,10‐dodecadienyl acetate, or with the codlemone isomer (E,Z)‐8,10‐dodecadienol. However, once activated by a pheromone stimulus, males no longer distinguish between a pheromone source and these antagonistic blend sources. This shows that the pheromone stimulus required for the initiation of an upwind flight response differs from the stimulus for maintaining upwind flight and landing at the source. In contrast to pheromone antagonists, males discriminate between pheromone alone and a blend source of pheromone and the plant volatile pear ester, ethyl (2E,4Z)‐2,4‐decadienoate. This indicates a difference in the detection and neural integration of pheromone and plant volatile stimuli.     

Control of diapausing codling moth,Cydia pomonella (Lepidoptera: Tortricidae) in wooden fruit bins,using entomopathogenic nematodes (Heterorhabditidae and Steinernematidae)

Stacked wooden fruit bins are frequent overwintering sites for overwintering diapausing codling moth larvae. Control strategies against the codling moth (Cydia pomonella) (Lepidoptera: Tortricidae) in South Africa have been hampered by the reinfestation of orchards from nearby stacked infested fruit bins and by the movement of infested bins between orchards. Worldwide, wooden fruit bins are systematically being replaced with plastic bins, however in South Africa this will not be accomplished in the near future. The objective of this study was to evaluate the potential of two recycled commercially available entomopathogenic nematode (EPN) species, Heterorhabditis bacteriophora and Steinernema feltiae, as well as of a local species, Steinernema yirgalemense, to disinfest miniature wooden fruit bins under controlled conditions in the laboratory. After dipping miniature bins loaded with codling moth larvae in a suspension of 25?IJs/mL of each of the three EPN species, under optimum conditions of temperature and humidity, the highest percentage of control was obtained using S. feltiae (75%). The addition of adjuvants significantly increased S. feltiae infectivity to >95%, whereas it did not result in a significant increase in H. bacteriophora or S. yirgalemense infectivity.     

苹果蠹蛾气味结合蛋白基因CpomOBP20的克隆及表达分析

[目的] 通过克隆苹果蠹蛾气味结合蛋白CpomOBP20基因cDNA序列,分析其序列特征和表达谱,旨在更好地了解OBP基因在苹果蠹蛾生命活动过程中的作用,为该害虫的绿色防控提供理论支撑。[方法] 采用RT-PCR法扩增苹果蠹蛾气味结合蛋白CpomOBP20基因cDNA序列,并使用生物信息学软件对其核苷酸和氨基酸序列进行分析;基于qPCR技术分析CpomOBP20基因在苹果蠹蛾4龄幼虫不同组织(头、血淋巴、表皮、脂肪体、中肠、马氏管和唾液腺)以及雌雄成虫不同末端组织(头、触角、下唇须、喙、足和翅)中的表达情况,利用分子对接研究了CpomOBP20与3种保幼激素的结合能力。[结果] 苹果蠹蛾气味结合蛋白CpomOBP20基因的开放阅读框长459 bp,共编码152个氨基酸,等电点为6.30,蛋白分子质量为16.264 ku,N末端具有20个氨基酸组成的信号肽序列,蛋白质序列中具有6个保守的半胱氨酸残基,属于Classical OBP。序列分析表明,CpomOBP20的氨基酸序列与小菜蛾OBP (XP_011557123.1)的一致性最高,在亲缘关系上更加接近。qPCR结果表明,CpomOBP20基因在苹果蠹蛾4龄幼虫以及雌雄成虫不同组织中均有表达,其中在4龄幼虫的血淋巴中表达量最高,在雌雄成虫表达量最高的分别是翅和足,其次是头部。分子对接结果表明,CpomOBP20与3种保幼激素均具有较好的结合能力,可能参与保幼激素的结合与转运。[结论] 本研究明确了CpomOBP20的核苷酸和氨基酸序列的组成及编码蛋白的理化性质,并推测CpomOBP20的作用可能不仅局限于嗅觉识别,在非嗅觉器官中也可能起着重要的生理作用,为今后更深入地探究气味结合蛋白在苹果蠹蛾生命活动中的作用机理提供数据支撑。