The infectivity and host range of Orgyia anartoides nucleopolyhedrovirus

The painted apple moth (PAM), Teia anartoides (Walker) (Lepidoptera: Lymantriidae) made a recent incursion into New Zealand. A nucleopolyhedrovirus (NPV), Orgyia anartoides NPV (OranNPV), originally isolated from PAM in Australia, was tested for its pathogenicity to PAM and a range of non‐target insect species found in New Zealand, to evaluate its suitability as a microbial control for this insect invader. Dosage‐mortality tests showed that OranNPV was highly pathogenic to PAM larvae; mean LT₅₀ values for third instars ranged from 17.9 to 8.1 days for doses from 10² to 10⁵ polyhedral inclusion bodies/larva, respectively. The cause of death in infected insects was confirmed as OranNPV. Molecular analysis established that OranNPV can be identified by PCR and restriction digestion, and this process complemented microscopic examination of infected larvae. No lymantriid species occur in New Zealand; however, the virus had no significant effects on species from five other lepidopteran families (Noctuidae, Tortricidae, Geometridae, Nymphalidae and Plutellidae) or on adult honeybees. Thus, all indications from this initial investigation are that OranNPV would be an important tool in the control of PAM in a future incursion of this species into New Zealand.     

Effects of SPLAT® GM sprayable pheromone formulation on gypsy moth mating success

Several integrated pest management programs rely on the use of mating disruption tactics to control insect pests. Some programs specifically target non‐native species, such as the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae). We evaluated SPLAT^® GM, a new sprayable formulation of the gypsy moth sex pheromone disparlure, for its ability to disrupt gypsy moth mating. The study was conducted in 2006, 2007, and 2008 in forested areas in Virginia, USA. Mating success of gypsy moth females was reduced by >99% and male moth catches in pheromone‐baited traps by >90%, in plots treated with SPLAT^® GM at dosages ranging from 15 to 75 g of active ingredient (a.i.) ha^?1. Dosage‐response tests conducted in 2008 indicated that SPLAT^® GM applied at a dosage of 7.5 g a.i. ha^?1 was as effective as a 15 g a.i. ha^?1 dosage.     

Potential for controlling codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) in Argentina using the sterile insect technique and egg parasitoids

Codling moth is the main pest affecting apples and pears worldwide. Most pest control strategies used against this insect have relied on the use of broad‐spectrum insecticides which have led to non‐desirable effects like pesticide resistance, residues in the environment, human health concerns and the reduction of access to international markets. Therefore, alternative pest control strategies that would result in sustainable fruit production systems while taking care of the environment are strongly promoted. The use of the sterile insect technique has proven to be a valuable pest control tactic within area‐wide integrated pest management strategies, and its synergistic effect for Lepidoptera pests when combined with other biological control tactics such as parasitoids has been documented. The purposes of this research were to evaluate the response of an Argentinean codling moth strain to a sub‐sterilizing radiation dose of 100 Gy and to assess the acceptability and suitability of sterile codling moth eggs by the egg parasitoids, Trichogramma cacoeciae (Marchal) and Trichogramma nerudai (Pintureau and Gerding). Irradiated female moths survived better than irradiated male moths and non‐irradiated male and female moths. Also, the fecundity of irradiated female moths was reduced by more than 30% as compared to non‐irradiated ones whereas their fertility was close to zero. The F₁ generation was male biased with a lower fertility (inherited sterility) than the parental generation. Trichogramma cacoeciae and T. nerudai parasitized both fertile and sterile eggs. However, there was a significant reduction in acceptability for sterile eggs. Trichogramma nerudai parasitized more eggs than T. cacoeciae, but egg acceptability for this species was proportionally lower than for T. cacoeciae especially on eggs oviposited by irradiated females. Development to adult of both parasitoids species was not substantially affected by the origin of the eggs and the wasps had acceptable levels of adult emergence, survival and fecundity. These results provided useful information on the potential for controlling the codling moth using egg parasitoids and the sterile insect technique in Argentina.     

Improved quality management to enhance the efficacy of the sterile insect technique for lepidopteran pests

Lepidoptera are among the most severe pests of food and fibre crops in the world and are mainly controlled using broad spectrum insecticides. This does not lead to environmentally sustainable control and farmers are demanding alternative control tools which are both effective and friendly to the environment. The sterile insect technique (SIT), within an area‐wide integrated pest management (AW‐IPM) approach, has proven to be a powerful control tactic for the creation of pest‐free areas or areas of low pest prevalence. Improving the quality of laboratory‐reared moths would increase the efficacy of released sterile moths applied in AW‐IPM programmes that integrate the (SIT). Factors that might affect the quality and field performance of released sterile moths are identified and characterized in this study. Some tools and methods to measure, predict and enhance moth quality are described such as tests for moth quality, female moth trapping systems, ‘smart’ traps, machine vision for recording behaviour, marking techniques, and release technologies. Methods of enhancing rearing systems are discussed with a view to selecting and preserving useful genetic traits that improve field performance.     

Improvement of the sterile insect technique for codling moth Cydia pomonella (Linnaeus) (Lepidoptera Tortricidae) to facilitate expansion of field application

The codling moth Cydia pomonella (L.) (Lepidoptera Tortricidae) is a key pest of pome fruit (apple, pear and quince) and walnut orchards in most temperate regions of the world. Efforts to control the codling moth in the past mostly relied on the use of broad spectrum insecticide sprays, which has resulted in the development of insecticide resistance, and the disruption of the control of secondary pests. In addition, the frequent reliance and use of these insecticides are a constant threat to the environment and human health. Consequently, there have been increased demands from the growers for the development of codling moth control tactics that are not only effective but also friendly to the environment. In that respect, the sterile insect technique (SIT) and its derivative, inherited sterility (IS), are, together with mating disruption and granulosis virus, among the options that offer great potential as cost‐effective additions to available control tactics for integration in area‐wide integrated pest‐management approaches. In support of the further development of the SIT/IS for codling moth control, the Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture implemented a 5‐year Coordinated Research Project (CRP) entitled ‘Improvement of codling moth SIT to facilitate expansion of field application’. Research focussed on sterile codling moth quality and management (e.g. mobility and life‐history traits in relation to rearing strategy, dispersal, flight ability, radiosensitivity and mating compatibility) and a better understanding of the basic genetics of codling moth to assist the development of genetic sexing strains (e.g. cytogenetics, the development of dominant conditional lethal mutations, molecular characterization of the sex chromosomes, sex identification in embryos and cytogenetic markers). The results of the CRP are presented in this special issue.     

Diversity and distribution of leaf mining insects on birches (<Emphasis Type="Italic">Betula</Emphasis> spp.) in Siberia

The diversity and distribution of leaf mining insects developing on birches (Betula spp.) in Siberia were reviewed based on published records and our observations. Analysis of the literature revealed 52 species of leaf miners recorded as feeding on different Betula species in Siberia. Among them, three species were listed under different names and six species were erroneously recorded as birch consumers. Thus, the revised list of birch leaf miners contains 44 species. Five moth and four sawfly species are mentioned in the literature as pests of Betula. Four sawflies are known to be invasive in North America. Our collections comprised 25 species, including the micro-moth Stigmella continuella (Lepidoptera, Nepticulidae), a new species for Siberia found in Novosibirsk. Immature stages of 15 species were identified using DNA barcoding. Twenty species were recorded from several regions of Siberia for the first time. The dominant group is Lepidoptera (31 species), followed by Coleoptera (7), Hymenoptera (5), and Diptera (1). Two-thirds of all the known leaf miners develop exclusively on birches; the remaining species also colonize alders (Alnus, Betulaceae), some Rosaceae, Salicaceae, and Ulmaceae. In our observations, the majority of insects (96%) developed on B. pendula. About half of them were also observed on the East Asian birches B. dahurica, B. divaricata, B. costata, B. ermanii, and B. gmelinii; five species were found on the North American birches B. occidentalis and B. papyrifera. All the leaf mining species listed in our paper for Siberia also occur in Europe. The similarity between the miner faunas of these regions is discussed and it is warned about possible errors in diagnostics of the Siberian species using the keys and catalogues for the European fauna. The importance of DNA barcoding in the study of the local insect faunas of poorly explored regions is also emphasized.     

Comparison of laboratory and field bioassays of laboratory‐reared Cydia pomonella (Lepidoptera: Tortricidae) quality and field performance

Maximum production and fitness of insect species that are mass‐reared for biological control programmes such as the sterile insect technique (SIT) have benefitted from the employment of quality control and quality management. With a growing interest in the use of SIT as a tactic for the suppression/eradication of key lepidopteran pests, such as the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), there is a parallel interest in inexpensive bioassays that can accurately detect differences in insect quality and monitor insect field performance. In this study, we examined laboratory (mating and flight ability) bioassays and field (field cage and open field release) bioassays simultaneously to discern the ability of the different bioassays to predict quality and field performance of codling moths produced in a commercial mass‐rearing facility. Moth quality was degraded by different levels of radiation during the sterilization procedure. Both the laboratory flight bioassay and the field cage bioassay successfully detected quality and performance differences that were relevant to moth performance in the field. However, the study data suggest that the field cage bioassay was a better predictor of the daily performance of males that had been released in the orchard than the laboratory flight bioassay. Conversely, data suggest that the controlled climatic conditions of the laboratory allowed the flight cylinder bioassay to be more sensitive in detecting daily fluctuations in the quality of moths caused by factors within the mass‐rearing facility. Therefore, both laboratory and field bioassays may be required to provide feedback on quality and performance of mass‐reared moths in a SIT programme.     

中国舞毒蛾六个地理种群的RAPD分析及SCAR标记构建

舞毒蛾Lymantria dispar L.是世界性农林害虫, 包含不同的亚种, 其中亚洲舞毒蛾的雌蛾具有较强的飞行能力, 已成为国际性的重要检疫性有害生物。然而, 不同舞毒蛾亚种及种群间形态难辨, 因此采用传统的手段鉴别舞毒蛾亚种种群是很困难的。本研究首先采用RAPD标记分析了中国舞毒蛾6个地理种群的遗传多态性。结果表明, 所检测的舞毒蛾种群的遗传分化系数G_st为0.7571, 由此推算出的平均有效迁移数（基因流参数）N_em为0.1604, 说明不同舞毒蛾种群间的遗传分化程度较高, 缺乏广泛的基因流动。本研究在RAPD遗传分析基础之上, 筛选出了4个舞毒蛾种群的特异性遗传位点, 然后对这些特异性位点进行了克隆测序、 序列分析和位点特异性引物设计。结果表明, 其中2个舞毒蛾种群的位点特异性引物可产生序列特征性扩增区域（SCAR）标记。经验证, 这些标记可被用来鉴别特定的舞毒蛾地理种群, 因此有助于对这些舞毒蛾地理种群的分布与扩散进行监测。     

A study of host specificity in the entomopathogenic fungus Beauveria bassiana (Hypocreales,Clavicipitaceae)

Beauveria bassiana (Balsamo – Crivelli) Vuillemin based mycoinsecticides are used against agricultural, veterinary and medical insect pests. The fungus has a very diverse and extensive host range. Variation in virulence among isolates of B. bassiana to different insect species has been abundantly documented. Given the effect of multiple factors on virulence, it is not certain whether the observed difference in virulence can be labelled as host specificity. Environmental conditions and susceptibility of the insect population are two main factors that affect successful fungal infection. Keeping the environmental factors constant, if virulence of an isolate to different insect species and different populations within an insect species is compared, the scale of difference between the two responses can be estimated. If differences in virulence of an isolate to different insect species are greater than the difference in virulence to different insect populations within an insect species, then, the isolate can be considered as exhibiting specific preference to those insect species towards which it exhibits high virulence. To examine this feature, a worldwide sample of B. bassiana was bioassayed on nine insect species and two different populations within two insect species. Laboratory bioassays were done on: Bombyx mori (Lepidoptera), Spodoptera litura (Lepidoptera), Chilo partellus (Lepidoptera), Helicoverpa armigera (Lepidoptera), Epilachna vigintioctopunctata (Coleoptera), Mylabris pustulata (Coleoptera), Aphis craccivora (Homoptera), Maconellicoccus hirsutus (Hemiptera) and Oecophylla smaragdina (Hymenoptera). The range of variation in virulence of a B. bassiana isolate to different insect species was not more than that observed with different populations within a single insect species. B. bassiana is thus a generalist with no strict host preference. B. bassiana based biopesticide can be used as a broad spectrum insecticide against a myriad of insect pests.     

Genetics‐based methods for agricultural insect pest management

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A behavioural study to help clarify how undersowing with clover affects host-plant selection by pest insects of brassica crops

Laboratory and field-cage tests were done to determine how undersowing brassica plants (Brassica oleraceae L. and B. rapa L.) (Cruciferae) with subterranean clover (Trifolium subterraneum L.) (Papilionaceae) affected host-plant selection by eight pest insect species of brassica crops. The pest species tested were Pieris rapae (Lepidoptera: Pieridae) (the small white butterfly), Pieris brassicae (Lepidoptera: Pieridae) (the large white butterfly), Delia radicum (Diptera: Anthomyiidae) (the cabbage root fly), Phaedon cochleariae (Coleoptera: Chrysomelidae) (the mustard beetle), Plutella xylostella (Lepidoptera: Yponomeutidae) (the diamond-back moth), Evergestis forficalis (Lepidoptera: Pyralidae) (the garden-pebble moth), Mamestra brassicae (Lepidoptera: Noctuidae) (the cabbage moth) and Brevicoryne brassicae (Hemiptera: Aphididae) (the cabbage aphid). In all tests, except two in which the brassica plants were about three times as high as the clover background, 39%–100% fewer of the pest insect stage monitored were found on host plants presented in clover than on those presented in bare soil. Contrary to claims supporting the ‘enemies hypothesis’, differences in colonization alone appeared sufficient to account for the lower numbers of insects found when host plants are undersown with clover. To be effective in reducing plant colonization, the clover must cover 50%, and preferably more, of the vertical profile of the crop plants. As clover used as an undersown crop often has to be cut to make it less competitive with the main brassica crop, temporal aspects of the condition of the clover during critical periods of pest activity need to be recorded carefully before concluding that undersowing does not produce the effect desired against certain pest species under field conditions. The effective clover barrier is like any other treatment, if it is not present at the appropriate time it cannot be expected to reduce pest insect numbers.     

Colonization of eucalypts in New Zealand by Australian insects

Since the 1860s, Australian insects have steadily colonized eucalypts in New Zealand. The rate of colonization has increased markedly over the last two decades. This increase may be related to increasing trade between the two countries. Currently there are 26 specialist eucalypt insect species and approximately 31 polyphagous insect species that can feed on Eucalyptus in New Zealand. The specialist eucalypt insects endemic to Australia have generally caused more damage than polyphagous or native insects. Eucalypt‐specific insects are dominated by sap sucking bugs, particularly psyllids, and defoliating Coleoptera and Lepidoptera. In some cases the major insect pest species have been those that are only occasional pests in Australia, for example Gonipterus scutellatus, Ctenarytaina eucalypti, Eriococcus coriaceus and Phylacteophaga froggatti. Some important insect pests have been rare, or even not described from Australia, prior to their appearance as a pest in New Zealand, for example Paropsis charybdis and Ophelimus eucalypti. Invading eucalypt insects are more likely to establish in the Auckland region than anywhere else in New Zealand.     

Quality of mass-reared codling moth (Lepidoptera: Tortricidae) after long-distance transportation: 1. Logistics of shipping procedures and quality parameters as measured in the laboratory

The sterile insect technique (SIT) is a proven effective control tactic against lepidopteran pests when applied in an areawide integrated pest management program. The construction of insect mass-rearing facilities requires considerable investment and moth control strategies that include the use of sterile insects could be made more cost-effective through the importation of sterile moths produced in other production centers. For codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), this is an attractive option because mating studies have confirmed the absence of mating barriers between codling moth populations from geographically different areas. To assess the feasibility of long-distance transportation of codling moths, pupae and adult moths were transported in 2004 from Canada to South Africa in four shipments by using normal commercial transport routes. The total transport time remained below 67 h in three of the consignments, but it was 89 h in the fourth consignment. Temperature in the shipping boxes was fairly constant and remained between -0.61 and 0.16 degrees C for 76.8-85.7% of the time. The data presented indicate that transporting codling moths as adults and pupae from Canada to South Africa had little effect on moth emergence, longevity, and ability to mate, as assessed in the laboratory. These results provide support to the suggestion that the STT for codling moth in pome fruit production areas might be evaluated and implemented by the importation of irradiated moths from rearing facilities in a different country or hemisphere.     

Micro-managing arthropod invasions: eradication and control of invasive arthropods with microbes

Non-indigenous arthropods are increasingly being introduced into new areas worldwide and occasionally they cause considerable ecological and economic harm. Many invasive arthropods particularly pose problems to areas of human habitation and native ecosystems. In these cases, the use of environmentally benign materials, such as host-specific entomopathogens, can be more desirable than broader spectrum control tactics that tend to cause greater non-target effects. The majority of successful eradication programs using arthropod pathogens have targeted invasive Lepidoptera with Bacillus thuringiensis kurstaki (Btk), such as eradication efforts against the gypsy moth, Lymantria dispar (L.), in North America and New Zealand. Both Btk and Lymantria dispar nucleopolyhedrovirus have been successfully used in efforts to limit the spread of L. dispar in the United States. For invasive arthropod species that are well established, suppression programs have successfully used arthropod-pathogenic viruses, bacteria, fungi and nematodes for either short- or long-term management. We will summarize the use of pathogens and nematodes in invasive arthropod management programs within a general context, and compare the use of microbes in gypsy moth management with diverse microbes being developed for use against other invasive arthropods.     

Characterization of an Insecticidal Protein from <Emphasis Type="Italic">Withania somnifera</Emphasis> Against Lepidopteran and Hemipteran Pest

Lectins are carbohydrate-binding proteins with wide array of functions including plant defense against pathogens and insect pests. In the present study, a putative mannose-binding lectin (WsMBP1) of 1124 bp was isolated from leaves of Withania somnifera. The gene was expressed in E. coli, and the recombinant WsMBP1 with a predicted molecular weight of 31 kDa was tested for its insecticidal properties against Hyblaea puera (Lepidoptera: Hyblaeidae) and Probergrothius sanguinolens (Hemiptera: Pyrrhocoridae). Delay in growth and metamorphosis, decreased larval body mass and increased mortality was recorded in recombinant WsMBP1-fed larvae. Histological studies on the midgut of lectin-treated insects showed disrupted and diffused secretory cells surrounding the gut lumen in larvae of H. puera and P. sanguinolens, implicating its role in disruption of the digestive process and nutrient assimilation in the studied insect pests. The present study indicates that WsMBP1 can act as a potential gene resource in future transformation programs for incorporating insect pest tolerance in susceptible plant genotypes.     

A Theoretical Approach to Analyze the Parametric Influence on Spatial Patterns of <Emphasis Type="Italic">Spodoptera frugiperda</Emphasis> (J.E. Smith) (Lepidoptera: Noctuidae) Populations

Studies of the influence of biological parameters on the spatial distribution of lepidopteran insects can provide useful information for managing agricultural pests, since the larvae of many species cause serious impacts on crops. Computational models to simulate the spatial dynamics of insect populations are increasingly used, because of their efficiency in representing insect movement. In this study, we used a cellular automata model to explore different patterns of population distribution of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), when the values of two biological parameters that are able to influence the spatial pattern (larval viability and adult longevity) are varied. We mapped the spatial patterns observed as the parameters varied. Additionally, by using population data for S. frugiperda obtained in different hosts under laboratory conditions, we were able to describe the expected spatial patterns occurring in corn, cotton, millet, and soybean crops based on the parameters varied. The results are discussed from the perspective of insect ecology and pest management. We concluded that computational approaches can be important tools to study the relationship between the biological parameters and spatial distributions of lepidopteran insect pests.     

<Emphasis Type="Italic">Oenothera speciosa</Emphasis> versus <Emphasis Type="Italic">Macroglossum stellatarum</Emphasis>: killing beauty

Hovering and dead individuals of the diurnal hawk-moth Macroglossum stellatarum (Linnaeus, 1758) (Lepidoptera: Sphingidae) were found with proboscides got stuck into flowers of the ornamental plant Oenothera speciosa Nutt (Onagraceae). The phenomenon was observed in several locations in Bulgaria where the plant has been introduced. Microscopic examination revealed that the reason for this unusual interaction is pubescence of thick-walled basiscopically oriented trichomes in the basal part of the hypanthium and style of the plant. When a foraging moth inserts its proboscis into this area, the tips of the trichomes are inserted into the transverse grooves of proboscis and hamper its back movement. As a result the moths are suspended for a long time, sometimes until death. Other trapped moth species were also observed but they always effected self-release. This plant–insect interaction is also a conservation issue as an estimation of its impact on wild insect populations is lacking.     

Constancy,Distribution, and Frequency of Lepidoptera Defoliators of <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> and <Emphasis Type="Italic">Eucalyptus urophylla</Emphasis> (Myrtaceae) in Four Brazilian Regions

The growth of the Brazilian forest sector with monocultures favors the adaptation of Arthropoda pests. The Lepidoptera order includes major pests of Eucalyptus spp. (Myrtaceae). The aim of this work is to study the population constancy, distribution, and frequency of Lepidoptera primary pests of Eucalyptus spp. Lepidoptera pests in Eucalyptus spp. plantations were collected in Três Marias and Guanhães (state of Minas Gerais), Niquelândia (state of Goiás), and Monte Dourado (state of Pará), Brazil, for a period of 5 years, with light traps and captures, every 15 days, for every region. The number of primary pest species (12) has been similar in the four regions, and even with 1.5 to 2.4% of the total species collected, this group has shown a high frequency, especially in Três Marias, Niquelândia, and Monte Dourado, with 66.3, 54.2, and 40.0% of the individuals collected, respectively, for 5 years. The primary pest species have been constant and frequent in all the regions, with population peaks from February to September in Três Marias, February and May in Niquelândia, and from July to September in Monte Dourado. The highest population peaks of these species have been recorded when the Eucalyptus spp. plants are 3 to 6 years old. The Guanhães region is more stable and, therefore, has a lower possibility of outbreaks of the Lepidoptera primary pest species.     

Towards a global barcode library for Lymantria (Lepidoptera: Lymantriinae) tussock moths of biosecurity concern

Background

Detecting and controlling the movements of invasive species, such as insect pests, relies upon rapid and accurate species identification in order to initiate containment procedures by the appropriate authorities. Many species in the tussock moth genus Lymantria are significant forestry pests, including the gypsy moth Lymantria dispar L., and consequently have been a focus for the development of molecular diagnostic tools to assist in identifying species and source populations. In this study we expand the taxonomic and geographic coverage of the DNA barcode reference library, and further test the utility of this diagnostic method, both for species/subspecies assignment and for determination of geographic provenance of populations.

Methodology/Principal Findings

Cytochrome oxidase I (COI) barcodes were obtained from 518 individuals and 36 species of Lymantria, including sequences assembled and generated from previous studies, vouchered material in public collections, and intercepted specimens obtained from surveillance programs in Canada. A maximum likelihood tree was constructed, revealing high bootstrap support for 90% of species clusters. Bayesian species assignment was also tested, and resulted in correct assignment to species and subspecies in all instances. The performance of barcoding was also compared against the commonly employed NB restriction digest system (also based on COI); while the latter is informative for discriminating gypsy moth subspecies, COI barcode sequences provide greater resolution and generality by encompassing a greater number of haplotypes across all Lymantria species, none shared between species.

Conclusions/Significance

This study demonstrates the efficacy of DNA barcodes for diagnosing species of Lymantria and reinforces the view that the approach is an under-utilized resource with substantial potential for biosecurity and surveillance. Biomonitoring agencies currently employing the NB restriction digest system would gather more information by transitioning to the use of DNA barcoding, a change which could be made relatively seamlessly as the same gene region underlies both protocols.