Long flights in Cydia pomonella L. (Lepidoptera: Tortricidae) measured by a flight mill: influence of sex, mated status and age

Abstract. The flight capacity of Cydia pomonella L. (Lepidoptera: Tortricidae) was measured in the laboratory by using computer-linked flight mills. Codling moths showed a large variation in flight capacity between individuals. We defined arbitrarily a longest single flight (LSF) of more than 5 km as an index for long-flyers. About 16.7% of virgin and 10.0% of mated males and 20.0% of virgin and 7.4% of mated females undertook such flights. Based on the LSF and the total distance flown (TDF^we concluded that males and females have little or no difference in flight capacity and that both the within-and between-habitat flights are similar in number and magnitude for both sexes. In the field, females are therefore potentially able to undertake flights of up to 11 km, as reported for males by other authors. This ability was highest at ages of 2–7 days after emergence, i.e. the first third of their lifetime, for virgin and mated male moths and for virgin female moths. Mated females showed peak flight capacity between 1 and 3 days after eclosion, which corresponded with the major egg-laying period. Few long flights were undertaken before oviposition. These findings do not agree with the oogenesis flight syndrome described by other authors, and this theory is believed not to apply to C.pomonella. Our laboratory results are discussed in relation to field experiments in general and hypotheses are developed about the significance of long-flyers for this species.     

Influence of juvenile hormone and mating on oogenesis and oviposition in the codling moth,Cydia pomonella

Oogenesis in the codling moth, Cydia pomonella, and the role of juvenile hormones (JHs) were addressed. Rudimentary ovarian structures were recognisable in day 3–4 pupae, when haemolymph JH was still undetectable by coupled gas chromatography‐mass spectrometry in the selected ion mode (GC‐MS/SIM). The presence of developing oocytes was observed by light microscopy on day 8, coincident with very low JH titres (0.74 ± 0.05 ng/ml JH II). Chorionation was only evident upon emergence, following an increase in JH in the pharate adult (0h old: 4.71 ± 0.34 ng/ml JH II). Analysis of haemolymph from virgin and mated females indicated that JH II was predominant, with approximately equal and lower quantities of JHs I and III (3.3‐ to 5.0‐fold less). When pupae or newly emerged adults were treated with JH homologues, no alteration in ovarian protein content was apparent, but the JH mimetic, fenoxycarb, depressed the number of oocytes filling ≥ 50% follicular volume. Chorion deposition was stimulated by JHs I, II, or III (10 μg), but not by fenoxycarb (0.05 μg, 10 μg). Mating provided correct stimuli for enhanced choriogenesis and egg laying, and, since haemolymph JH titres were concomitantly elevated (approximately 2‐fold), it was postulated that the rise in JH elicited both these events. Application of JHs to virgin females, however, could not mimic mating; only increases in choriogenesis were induced: JH‐treatment of virgins (or mated insects) significantly decreased oviposition rates over 24 and 48 h and markedly reduced the life‐time total number of eggs. Arch. Insect Biochem. Physiol. 41:186–200, 1999. © 1999 Wiley‐Liss, Inc.     

Antennal and behavioural response of codling moth Cydia pomonella to plant volatiles

Identification of host volatile compounds attractive to codling moth Cydia pomonella, a most important insect of apple, will contribute to the development of safe control techniques. Synthetic apple volatiles in two doses were tested for antennal and behavioural activity in codling moth. Female antennae strongly responded to (Z)3‐hexenol, (Z)3‐hexenyl benzoate, (Z)3‐hexenyl hexanoate, (±)‐linalool and E,E‐α‐farnesene. Two other compounds eliciting a strong antennal response were the pear ester, ethyl (E,Z)‐2,4‐decadienoate, and its corresponding aldehyde, E,E‐2,4‐decadienal, which is a component of the larval defence secretion of the European apple sawfly. Attraction of codling moth to compounds eliciting a strong antennal response was tested in a wind tunnel. Male moths were best attracted to a blend of (E,E)‐α‐farnesene, (E)‐beta‐farnesene and ethyl (E,Z)‐2,4‐decadienoate. The aldehyde E,E‐2,4‐decadienal had an antagonistic effect when added to the above mixture.     

Isolation of microsatellite loci in the codling moth,Cydia pomonella (Lepidoptera: Tortricidae)

Cydia pomonella L. is an important insect pest of pome fruits worldwide. We have isolated and characterized 17 microsatellite loci from the enriched genomic libraries constructed using a biotin/streptavidin capture protocol. Among these loci, 11 were scored polymorphic when 50 individuals from a laboratory population were screened. Their alleles numbered two to four, with the observed heterozygosity (H_O) ranging from 0.114 to 0.404. Successful amplification was obtained for all these loci when the designed primers were tested, showing the promise of use in genetic mapping and population studies.     

苹果蠹蛾成虫产卵特性

苹果蠹蛾Cydia pomonella(L.)是全球温带地区果园主要害虫之一,是中国的重要检疫性有害生物,对我国苹果、梨等水果的安全生产造成极大危害及威胁。为详细了解苹果蠹蛾的产卵特性,从而为进行有效的监测与防控提供基础信息,作者于2006年在甘肃省山丹县梨果园中对树冠不同高度与朝向的蛀果率进行了调查,并于2010在内蒙古阿拉善左旗对梨树果枝上不同部位的产卵量进行了详细调查。主要研究结果如下:1)树冠2.5m以上的蛀果率显著高于2.5m以下的蛀果率,树冠东面的蛀果率最高,南面的蛀果率最低;2)在整个果园中,靠近北侧的果树上果实受害程度要高于南侧果树上的果实受害程度,整个果园中蛀果率由北向南逐渐降低;3)叶片上的卵数最多,占总卵数的73.1%,果实上的卵数次之,占总卵数的14.6%,枝条上的卵数最少,占总卵数的12.2%;4)在产卵的叶片上,卵主要产在叶背面,叶片背面卵量是叶正面的6.65倍。鉴于以上研究结果,在开展化学防治或颗粒体病毒防治时,应注意充分喷施果树上层树冠,且在对果实进行处理的同时,叶片和枝条也需要充分喷药。     

Response of Cydia pomonella to selection on mobility: laboratory evaluation and field verification

1. The codling moth Cydia pomonella (L.), largely regarded as a sedentary species, shows great variation in flight capacity among individuals in the laboratory, as has been reported for tethered flight. The occurrence of individuals with the ability to fly over long distances is considered ecologically significant for the colonisation of new habitats in response to deteriorating environmental conditions. The work reported here was designed to investigate the importance of the genetic component in regulating dispersal in C. pomonella. 2. Bi‐directional selection on mobility measured by actograph was carried out in the laboratory. Both male and female codling moths responded significantly to the upward and downward selections. Divergence between the two selected strains occurred after one generation of selection and increased as further selections continued. The realised heritabilities for mobility were estimated as 0.43 in males and 0.29 in females when averaged from the two selection directions. 3. The dispersal capacity of the selected mobile and sedentary strains was verified by mark–release–recapture experiments in the field, though only the released male moths were captured effectively. Flight distances by males differed significantly between the two strains, with the mobile strain showing a greater dispersal capacity than the sedentary strain. 4. This study demonstrated a positive correlation between mobility measured by actograph and field dispersal capacity in the codling moth. Furthermore, it provides the first experimental data to show field performances of different genotypes in insect dispersal.     

苹果蠹蛾幼虫爬行特性

本文通过收集苹果和梨树上的蛀果模拟自然落果,研究了苹果蠹蛾Cydia pomonella(L.)脱果幼虫的爬行特性。结果发现,58.91%的幼虫钻出蛀果进行了爬行,而41.09%滞留于果堆内部;在进行爬行的幼虫中,50%的幼虫爬行距离在0～1m之间,95%的幼虫爬行距离在0～7m之间,这意味着在实际防治过程中,落果周围0到7m的范围都需要做防治处理,而0～1m的范围需要重点防治;幼虫在果堆放置后的0～25d持续脱果,表明当果园内有落果时需要马上及时清理;幼虫结茧的高度大部分在50cm以下,在实际防治过程中,树干缚带诱杀幼虫时应将诱集带设置在距地面0～0.5m的主干上,以保证落果幼虫也可以被诱集带捕获。     

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.     

Prospection and molecular analysis of CpGV isolates infecting Cydia pomonella at different geographical locations in Argentina

The occurrence and genetic diversity of Cydia pomonella granulovirus infecting C. pomonella across Argentina were investigated. Larvae were collected from fruit orchards in regions where CpGV‐based biopesticides have been extensively used and then discontinued (Catamarca) or are still being used (Alto Valle). The survey was also extended to regions where few occasional (i.e. Mendoza) or no virus treatments (various locations) have been made. PCR analysis showed an unexpectedly high proportion of infected larvae (31.3–50%) at most sampling sites in Catamarca. Phylogenetic analysis of these samples, based on gran and lef‐8 genes partial sequences, revealed a previously unreported CpGV variant which could not be assigned to any of the known CpGV genome types and formed a well‐defined new cluster. Instead, samples from Alto Valle were genetically similar to isolate CpGV‐M (the active ingredient in commercial formulations). There, the percentage of infected individuals was considerably lower (1.8–21.9%). The virus was not detected in Mendoza or the other sampling regions. Implications of these results on the epidemiology and current classification of CpGV isolates are discussed.     

Juvenile hormone catabolism and oviposition in the codling moth, Cydia pomonella, as functions of age, mating status, and hormone treatment.

In vitro catabolism of juvenile hormone (JH) in haemolymph of adult female Cydia pomonella was ascribed mainly to juvenile hormone esterase (JHE) activity. No significant differences were noted between virgin and mated females 0-96 h post-emergence. Changes in JHE activity did not appear dependent upon fluctuations in JH titre; conversely, changes in JHE activity could not explain the changes in JH titres. Maximal JHE activity was recorded at 24 h (331.47 +/- 47.25 pmol/h/microl; 355.93 +/- 36.68 pmol/h/microl, virgin; mated insects, respectively) and preceded the peak in JH titres at 48 h. Topical application of JH II (10 ng-10 microg) or fenoxycarb (50 ng) enhanced JHE activity up to 640 and 56%, respectively. Treatment upon emergence with 10 microg JH II induced enzymic activity for less than 24 h, and when 10 microg JH II or 50 ng fenoxycarb were applied, circulating JH titres returned to control levels within 24 h. Oviposition was highly sensitive to exogenous JH and declined significantly with dosages >100 pg. To allow a degree of oocyte maturation before JH treatment, the hormone was administered at 6, 12, 24, or 48 h post-emergence and/or females were mated. Neither measure "protected" the system; oviposition declined immediately after JH application.     

甘肃酒泉苹果蠹蛾的发生规律

苹果蠹蛾Cydia pomonella(L.)是我国重要的果树害虫和检疫对象。本文通过田间调查和性诱芯诱捕器诱捕的方法,研究了2008年苹果蠹蛾在甘肃酒泉的年发生规律和空间分布特性。结果表明,苹果蠹蛾在我国甘肃酒泉1年发生2代;越冬代和第1代成虫发生高峰期分别为5月上旬至中旬和7月上旬至中旬,成虫在树冠的中层、向阳的方向(东部和南部)、果实和叶背面产卵较多;幼虫发生的两次高峰分别发生在6月17日和7月26日,刚孵化幼虫很快蛀果隐蔽为害,给防治带来很大困难;幼虫化蛹前,主要从树的上部向下爬行,并常以老熟幼虫潜入树干或分枝的树皮下结茧化蛹或越冬,次年4月中下旬开始羽化。     

Control efficacy of Bacillus thuringiensis and a new granulovirus isolate against Cydia pomonella in orchards

Abstract

Codling moth, Cydia pomonella, is one of the most serious pests of apple and pear worldwide. This study evaluates the efficacies of a granulovirus, a Bacillus thuringiensis (Bt) strain and their combination in the control of C. pomonella in China. A Cydia pomonella granulovirus (CpGV) was isolated from C. pomonella cadavers in an orchard in Gansu, China. Droplet-feeding bioassays showed the median lethal concentration (LC₅₀) of this CpGV isolate (CpGV-C1) against the third instar C. pomonella larvae was 770 OBs µl^?1. The LC₅₀ values of Bt C-33 and kurstaki HD-1 against the third instar larvae were 26.3 µg ml^?1 and 15.7 µg ml^?1, respectively. Field tests indicated the control efficacies of CpGV-C1 and the combination of CpGV-C1 and Bt against C. pomonella larvae in apple orchards were similar to that of beta-cypermethrin. Our data demonstrated that the combination of CpGV and Bt might effectively protect apple fruits from the damage of C. pomonella larvae and had the potential to be developed as a low-cost, highly effective insecticide.     

苹果蠹蛾老熟幼虫诱杀技术

本文对简易杀虫诱集带诱杀苹果蠹蛾Cydia pomonella(L.)老熟幼虫的效果进行了研究。发现在编织袋,旧衣物,瓦楞纸3种材料中,旧衣物对苹果蠹蛾的老熟幼虫捕获效果最好,其诱捕量占总诱捕量的68.42%;在诱集带中添加的农药中(包括乐斯本、敌敌畏、白僵菌、灭幼脲3号、高效氯氰菊酯等),乐斯本的杀虫效果最好,幼虫死亡率达到98.20%;在不同浓度的乐斯本溶液中,500倍乐斯本杀虫效果最好,幼虫死亡率达到91.61%,且对幼虫没有驱避作用;500倍乐斯本+50倍白僵菌药杀虫诱集带有效期长达40多天,37d后对幼虫的杀伤效果依然达到96%以上,作为老熟幼虫的防治措施十分理想。     

苹果蠹蛾成虫在苹果园中的动态分布

为了解苹果蠹蛾Cydia pomonella(L.)在田间的空间分布格局及其季节变化,从而为基于不同果园特点的诱捕器监测及有害生物综合治理提供基础信息,2005及2010年,本研究选择甘肃高台县和张掖甘州区的两处果园,应用地统计方法对其中的成虫空间分布及其季节性变化进行了研究。其结果显示:在采取常规防治的果园中,苹果蠹蛾发生热点集中在果园的边缘,且随着成虫数量季节性的消长,这种边界效应变的更加突出;而在采取了迷向防治措施的果园当中,诱捕器捕获量的空间相关性与信息素浓度和虫口数量有密切的关系。根据以上研究结果,在今后的监测工作中,尤其是在较大的果园中进行诱捕器布局的时候,应将果园的边缘地区作为重点监测区域。     

Odour quality discrimination for behavioural antagonist compounds in three tortricid species

The antennal and behavioural response of three tortricid species (Lepidoptera: Tortricidae) to their corresponding sex pheromones and known or putative behavioural antagonists was tested by electroantennography and in field trials. The species and their pheromones and known or proposed behavioural antagonist were lightbrown apple moth, Epiphyas postvittana (Walker) [pheromone: 95% (E)‐11‐tetradecenyl acetate (E11‐14Ac) and 5% (E,E)‐9,11‐tetradecadienyl acetate (E9E11‐14Ac); antagonist: (Z)‐11‐tetradecenyl acetate (Z11‐14Ac)], codling moth, Cydia pomonella (L.) [pheromone: (E,E)‐8,10‐dodecadien‐1‐ol (codlemone); antagonist: (E,E)‐8,10‐dodecadienyl acetate (codlemone acetate)], and gorse pod moth, Cydia ulicetana (Haworth) [pheromone: (E,E)‐8,10‐dodecadienyl acetate (codlemone acetate); putative antagonist: (E,E)‐8,10‐dodecadien‐1‐ol (codlemone)]. In all three species, the antennal response to the antagonists was not significantly different from the antennal response to con‐specific sex pheromone compounds. In the field trapping experiments, significantly fewer males of all three species were attracted to the respective pheromone when blended with the behavioural antagonist compound. However, this response varied between the species, with lightbrown apple moth and codling moth showing stronger responses to the antagonist compounds than gorse pod moth. Both lightbrown apple moth and codling moth males were able to discriminate between pure pheromone and pheromone blended with the antagonist when placed in traps side‐by‐side separated by ca. 10 cm. The presence of the behavioural antagonist not only affected the catch of males of both species within their own traps but also affected the catch in the neighbouring trap that contained con‐specific sex pheromone; the catch of gorse pod moth was not reduced by the presence of codlemone in the neighbouring trap. These results suggest that strong behavioural antagonists such as codlemone acetate for codling moth and Z11‐14Ac for lightbrown apple moth induce their inhibition effect at a substantial distance downwind from the odour source; however, most of those males that were able to overcome this inhibition effect at the early stage of orientation to odour source, were able to discriminate between the pheromone source and the pheromone source admixed with behavioural antagonist. Moderate behavioural antagonists such as codlemone for gorse pod moth did not elicit a discrimination effect.     

苹果蠹蛾性信息素诱捕器田间诱捕效应影响因子

苹果蠹蛾是我国重要的果树害虫和检疫对象.本文比较研究了性信息素诱捕器颜色、类型、放置位置、诱芯颜色及诱芯数量等对苹果蠹蛾雄性成虫诱捕效果的影响.结果表明：白色和绿色诱捕器的诱捕量是蓝色的2倍以上,诱捕效果显著优于后者;三角形诱捕器与水瓶式诱捕器的诱捕效果间不存在显著差异;放置在树冠中部的诱捕器诱蛾量是树冠上部的2倍左右,诱捕效果显著优于后者;诱芯颜色及诱芯数量对诱蛾量无显著影响.本研究结果可为苹果蠹蛾的性信息素监测技术提供指导.     

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.

     

A flight cylinder bioassay as a simple,effective quality control test for Cydia pomonella

Assessment of quality of the sterile male insects that are being mass‐reared for release in area‐wide integrated pest management programmes that include a sterile insect technique component is crucial for the success of these programmes. Routine monitoring of sterile male quality needs to be carried out both in the mass‐rearing facility and in the field. Simple bioassays that can be conducted in the laboratory and that would be surrogates for laborious field tests would be a very cost‐effective way of monitoring sterile male field performance. Simple flight cylinders were used to assess whether these could detect differences in quality of male codling moth Cydia pomonella. The number of male and female codling moths that flew out of the cylinders was influenced by cylinder diameter, cylinder height and number of hours following the initiation of the test. The flight cylinder bioassay was capable of detecting differences in quality of codling moths induced by irradiation when moths were shipped, but no differences were found in flight ability when the moths were not transported. The tests also confirmed that handling and shipment reduced quality more for irradiated than for non‐treated codling moth, and that insect quality was significantly influenced by larval rearing protocols. The flight cylinder bioassay was therefore successful in detecting differences in codling moth quality induced by various treatments that had been identified previously by more complex laboratory bioassays and field trials. Treatment differences were most likely detected when flight cylinders were 16 cm high.