Publications

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prey acceptability and preference of oenopia conglobata (coleoptera: coccinellidae), a candidate for biological control in urban green areas.oenopia conglobata is one of the most common ladybird species in urban green areas of the mediterranean region. we have obtained data about its prey acceptability and prey preferences. in a laboratory experiment, we investigated the acceptability of seven aphid and one psyllid species as prey for this coccinellid: the aphids chaitophorus populeti, aphis gossypii, aphis craccivoramonelliopsis caryae, eucallipterus tiliae, aphis nerii (on white poplar, pomegranate, false acacia, black walnut, lime ...201829329217
a large-scale field study of bacterial communities in cereal aphid populations across morocco.insects are frequently associated with bacteria that can have significant ecological and evolutionary impacts on their hosts. to date, few studies have examined the influence of environmental factors to microbiome composition of aphids. the current work assessed the diversity of bacterial communities of five cereal aphid species (sitobion avenae, rhopalosiphum padi, r. maidis, sipha maydis and diuraphis noxia) collected across morocco and covering a wide range of environmental conditions. we aim ...201829346623
biocidal potential and chemical composition of industrial essential oils from hyssopus officinalis, lavandula × intermedia var. super, and santolina chamaecyparissus.this work presents the biocidal (insecticidal, ixodicidal, nematicidal, and phytotoxic) effects and chemical compositions of three essential oils obtained from the industrial steam distillation (ieos) of hyssop (hyssopus officinalis l.), lavandin (lavandula × intermedia or l. × hybrida var. super), and cotton lavender (santolina chamaecyparissus l.). their chemical composition analyzed by gas chromatography coupled to mass spectrometry showed 1,8-cineole (53%) and β-pinene (16%) as the major com ...201828801935
the plant hormone salicylic acid interacts with the mechanism of anti-herbivory conferred by fungal endophytes in grasses.the plant hormone salicylic acid (sa) is recognized as an effective defence against biotrophic pathogens, but its role as regulator of beneficial plant symbionts has received little attention. we studied the relationship between the sa hormone and leaf fungal endophytes on herbivore defences in symbiotic grasses. we hypothesize that the sa exposure suppresses the endophyte reducing the fungal-produced alkaloids. because of the role that alkaloids play in anti-herbivore defences, any reduction in ...201829194664
comparative role of neem seed extract, moringa leaf extract and imidacloprid in the management of wheat aphids in relation to yield losses in pakistan.wheat being staple food of pakistan is constantly attacked by major wheat aphid species, schizaphis graminum (r.), rhopalosiphum padi (l.) and sitobion avenae (f.). due to concern on synthetic chemical use in wheat, it is imperative to search for alternative environment- and human- friendly control measures such as botanical pesticides. in the present study, we evaluated the comparative role of neem seed extract (nse), moringa leaf extract (mle) and imidacloprid (i) in the management of the aphi ...201728953894
metabolism or behavior: explaining the performance of aphids on alkaloid-producing fungal endophytes in annual ryegrass (lolium multiflorum).plant-herbivore interactions are often mediated by plant microorganisms, and the "defensive mutualism" of epichloid fungal endophytes of grasses is an example. these endophytes synthesize bioactive alkaloids that generally have detrimental effects on the performance of insect herbivores, but the underlying mechanisms are not well understood. our objective was to determine whether changes in the physiology and/or behavior of aphids explain the changes in performance of insects feeding on endophyt ...201728879573
insecticide resistance status and detoxification enzymes of wheat aphids sitobion avenae and rhopalosiphum padi. 201728755297
differences in egg hatching time between cyclical and obligate parthenogenetic lineages of aphids.many aphid species exhibit a variation in reproductive mode which is influenced by winter climate regimes, with cyclical parthenogenetic (cp) lines dominating in cold winter areas (because they produce cold-resistant eggs) and obligate parthenogenetic (op) ones in mild winter regions (because of their parthenogenetic overwintering). genetic studies on several aphid species have shown that the op trait can be transmitted during sexual events involving the 2 types of lines. this genetic system cou ...201728608995
plant water stress affects interactions between an invasive and a naturalized aphid species on cereal crops.in cereal cropping systems of the pacific northwestern united states (pnw), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. yet, it remains uncertain how interactions between herbivore species are affected by drought stress. here, interactions between two cereal aphids present in pnw cereal systems, metopolophium festucae (theobald) subsp. cerealium (a newly invasive species) and rhopalosiphum padi l. (a na ...201728430898
transcription of four rhopalosiphum padi (l.) heat shock protein genes and their responses to heat stress and insecticide exposure.the bird cherry-oat aphid, rhopalosiphum padi (l.), a worldwide destructive pest, is more heat tolerant than other wheat aphids, and it has developed resistance to different insecticides. heat shock proteins (hsps) play an important role in coping with environmental stresses. to investigate hsp transcriptional responses to heat and insecticide stress, four full-length hsp genes from r. padi (rphsp60, rphsc70, rphsp70-1, and rphsp70-2) were cloned. four rphsps were expressed during all r. padi de ...201728025068
overexpression and down-regulation of barley lipoxygenase lox2.2 affects jasmonate-regulated genes and aphid fecundity.aphids are pests on many crops and depend on plant phloem sap as their food source. in an attempt to find factors improving plant resistance against aphids, we studied the effects of overexpression and down-regulation of the lipoxygenase gene lox2.2 in barley (hordeum vulgare l.) on the performance of two aphid species. a specialist, bird cherry-oat aphid (rhopalosiphum padi l.) and a generalist, green peach aphid (myzus persicae sulzer) were studied. lox2.2 overexpressing lines showed up-regula ...201729257097
the protease inhibitor ci2c gene induced by bird cherry-oat aphid in barley inhibits green peach aphid fecundity in transgenic arabidopsis.aphids are phloem feeders that cause large damage globally as pest insects. they induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid (rhopalosiphum padi l.) affects aphid performance in the model plant arabidopsis thaliana l. a barley cdna encoding the protease inhibitor ci2c was expressed in a. tha ...201728632160
characterisation of imidacloprid resistance in the bird cherry-oat aphid, rhopalosiphum padi, a serious pest on wheat crops.rhopalosiphum padi is a destructive insect pest of wheat worldwide. studies have shown that r. padi has developed resistance to different insecticides, including imidacloprid. we studied the mechanisms conferring resistance to imidacloprid at the biochemical and molecular levels.201729266699
feeding by melanaphis sacchari (hemiptera: aphididae) facilitates use of sorghum by rhopalosiphum padi (hemiptera: aphididae), but reciprocal effects are negative.in the process of feeding, aphids modify the physiology of their host plants in species-specific ways, and plant responses to these aggressions are often genotype- or cultivar-specific. thus, different aphid species sharing a host can influence each other's fitness via plant-mediated interactions, usually with negative and asymmetric impacts. here, we show that feeding by the sugarcane aphid, melanaphis sacchari zehntner, can improve the suitability of sorghum as a host plant for the bird cherry ...201728073905
why is there no impact of the host species on the cold tolerance of a generalist parasitoid?for generalist parasitoids such as those belonging to the genus aphidius, the choice of host species can have profound implications for the emerging parasitoid. host species is known to affect a variety of life history traits. however, the impact of the host on thermal tolerance has never been studied. physiological thermal tolerance, enabling survival at unfavourable temperatures, is not a fixed trait and may be influenced by a number of external factors including characteristics of the stress, ...201729038015
the effect of landscape complexity and microclimate on the thermal tolerance of a pest insect.landscape changes are known to exacerbate the impacts of climate change. as such, understanding the combined effect of climate and landscape on agroecosystems is vital if we are to maintain the function of agroecosystems. this study aimed to elucidate the effects of agricultural landscape complexity on the microclimate and thermal tolerance of an aphid pest to better understand how landscape and climate may interact to affect the thermal tolerance of pest species within the context of global cli ...201728322022
the identification and expression analysis of candidate chemosensory genes in the bird cherry-oat aphid rhopalosiphum padi (l.).the bird cherry-oat aphid rhopalosiphum padi (l.) is one of the most important wheat pests with polyphagia and autumn migrants. and, chemosensory genes were thought to play a key role in insect searching their hosts, food and mate. however, a systematic identification of the chemosensory genes in this pest has not been reported. thus, in this study, we identified 14 odorant-binding proteins, nine chemosensory proteins, one sensory neuron membrane protein, 15 odorant receptors, 19 gustatory recep ...201729198196
morphological variation of aphidius ervi haliday (hymenoptera: braconidae) associated with different aphid hosts.parasitoids are frequently used in biological control due to the fact that they are considered host specific and highly efficient at attacking their hosts. as they spend a significant part of their life cycle within their hosts, feeding habits and life history of their host can promote specialization via host-race formation (sequential radiation). the specialized host races from different hosts can vary morphologically, behaviorally and genetically. however, these variations are sometimes incons ...201728713658
spatial and temporal dynamics of aphids (hemiptera: aphididae) in the columbia basin and northeastern oregon.aphid species, such as the potato aphid, macrosiphum euphorbiae thomas, and the green peach aphid, myzus persicae sulzer, are routinely considered the most important pests of potatoes. potato aphid, green peach aphid, and more recently, other aphids such as the bird cherry-oat aphid rhopalosiphum padi l. have been identified as vectors of multiple plant pathogenic viruses in potatoes. since 2006, an area-wide trapping network consisting of ∼60 sites was developed through collaboration between re ...201728510728
transcriptomics and alternative splicing analyses reveal large differences between maize lines b73 and mo17 in response to aphid rhopalosiphum padi infestation.maize (zea mays l.) is a staple crop worldwide with extensive genetic variations. various insects attack maize plants causing large yield loss. here, we investigated the responses of maize b73, a susceptible line, and mo17, a resistant line, to the aphid rhopalosiphum padi on metabolite and transcriptome levels. r. padi feeding had no effect on the levels of the defensive metabolites benzoxazinoids (bxs) in either line, and mo17 contained substantially greater levels of bxs than did b73. profili ...201729067035
enhanced aphid abundance in spring desynchronizes predator-prey and plant-microorganism interactions.climate change leads to phenology shifts of many species. however, not all species shift in parallel, which can desynchronize interspecific interactions. within trophic cascades, herbivores can be top-down controlled by predators or bottom-up controlled by host plant quality and host symbionts, such as plant-associated micro-organisms. synchronization of trophic levels is required to prevent insect herbivore (pest) outbreaks. in a common garden experiment, we simulated an earlier arrival time (~ ...201727858148
interactions among the predatory midge aphidoletes aphidimyza (diptera: cecidomyiidae), the fungal pathogen metarhizium brunneum (ascomycota: hypocreales), and maize-infesting aphids in greenhouse mesocosms.the generalist entomopathogenic fungus, metarhizium brunneum, has proved to have great potential as a versatile biological pest control agent. the gall midge aphidoletes aphidimyza is a specialist predator that occurs naturally in europe and has been successfully used for aphid suppression. however, the interaction between these two biological control organisms and how it may affect the biological control of aphids awaits further investigation. as part of the eu-supported project inbiosoil, this ...201728417909
viral metagenomics of aphids present in bean and maize plots on mixed-use farms in kenya reveals the presence of three dicistroviruses including a novel big sioux river virus-like dicistrovirus.aphids are major vectors of plant viruses. common bean (phaseolus vulgaris l.) and maize (zea mays l.) are important crops that are vulnerable to aphid herbivory and aphid-transmitted viruses. in east and central africa, common bean is frequently intercropped by smallholder farmers to provide fixed nitrogen for cultivation of starch crops such as maize. we used a pcr-based technique to identify aphids prevalent in smallholder bean farms and next generation sequencing shotgun metagenomics to exam ...201728969654
responses of holocyclic and anholocyclic rhopalosiphum padi populations to low-temperature and short-photoperiod induction.the different life cycles of aphid species make these organisms good models for studying the short-term consequences of sex. the bird cherry-oat aphid rhopalosiphum padi has a wide geographic distribution and correspondingly different life cycles. in this study, the life cycles of r. padi collected from six different regions in china were characterized experimentally by comparing the responses of holocyclic and anholocyclic populations to low-temperature and short-photoperiod induction. clones c ...201728303175
searching for wheat resistance to aphids and wheat bulb fly in the historical watkins and gediflux wheat collections.insect pests can reduce wheat yield by direct feeding and transmission of plant viruses. here we report results from laboratory and field phenotyping studies on a wide range of wheat, including landraces from the watkins collection deriving from before the green revolution, more modern cultivars from the gediflux collection (north-western europe) and modern uk elite varieties, for resistance to the bird cherry-oat aphid, rhopalosiphum padi (homoptera: aphididae) and the english grain aphid, sito ...201728303034
tps46, a rice terpene synthase conferring natural resistance to bird cherry-oat aphid, rhopalosiphum padi (linnaeus).plant terpene synthases (tpss) are key enzymes responsible for terpene biosynthesis, and can play important roles in defense against herbivore attack. in rice, the protein sequence of tps46 was most closely related to maize tps10. however, unlike maize tps10, tps46 was also constitutively expressed in rice even in the absence of herbivore attack. potential roles or constitutive emissions of specific volatiles may due to the constitutive expressions of tps46 in rice. therefore, in the present stu ...201728217135
stacked bt maize and arthropod predators: exposure to insecticidal cry proteins and potential hazards.genetically engineered (ge) crops with stacked insecticidal traits expose arthropods to multiple cry proteins from bacillus thuringiensis (bt). one concern is that the different cry proteins may interact and lead to unexpected adverse effects on non-target species. bi- and tri-trophic experiments with smartstax maize, herbivorous spider mites (tetranychus urticae), aphids (rhopalosiphum padi), predatory spiders (phylloneta impressa), ladybeetles (harmonia axyridis) and lacewings (chrysoperla car ...201728724730
resistance of select winter wheat (triticum aestivum) cultivars to rhopalosiphum padi (hemiptera: aphididae).the bird cherry-oat aphid (rhopalosiphum padi l.) is a global pest of wheat and vectors some of the most damaging strains of barley yellow dwarf virus (bydv). in years of heavy r. padi infestation, r. padi and bydv together reduce wheat yields by 30-40% in kansas and other states of the u.s. great plains wheat production area. cultivation of wheat cultivars resistant to r. padi can greatly reduce production costs and mitigate r. padi-bydv yield losses, and increase producer profits. this study i ...201728854661
crop-associated virus reduces the rooting depth of non-crop perennial native grass more than non-crop-associated virus with known viral suppressor of rna silencing (vsr).as agricultural acreage expanded and came to dominate landscapes across the world, viruses gained opportunities to move between crop and wild native plants. in the midwestern usa, virus exchange currently occurs between widespread annual poaceae crops and remnant native perennial prairie grasses now under consideration as bioenergy feedstocks. in this region, the common aphid species rhopalosiphum padi l. (the bird cherry-oat aphid) transmits several virus species in the family luteoviridae, inc ...201728688850
identification of an intraspecific alarm pheromone and two conserved odorant-binding proteins associated with (e)-β-farnesene perception in aphid rhopalosiphum padi.(e)-β-farnesene (ebf) is the common active component of aphid alarm pheromone. either or both of two orthologs of ordorant-binding proteins (obps), obp3 and obp7, recently reported in aphids, may be involved in ebf perception. the aim of this study was to investigate the respondence of the aphid rhopalosiphum padi to its intraspecific alarm pheromone and which obp is responsible for that response. we tested the olfactory response of the aphid r. padi to ebf and freshly crushed aphids. then, we e ...201728778653
biocidal effects of piper hispidinervum (piperaceae) essential oil and synergism among its main components.in this study we evaluated the effect of a pressure gradient (1-2 atm) in the extraction and composition of the essential oil (eo) of piper hispidinervum by steam distillation. we also evaluated the insect antifeedant effects (spodoptera littoralis, leptinotarsa decemlineata, myzus persicae and rhopalosiphum padi) and nematicidal activity (meloidogyne javanica) of the oils, their major components and their synergistic interactions. safrole was the major component (78-81%) followed by terpinolene ...201728416272
establishing alighting preferences and species transmission differences for pea seed-borne mosaic virus aphid vectors.pea seed-borne mosaic virus (psbmv) infection causes a serious disease of field pea (pisum sativum) crops worldwide. the psbmv transmission efficiencies of five aphid species previously found landing in south-west australian pea crops in which psbmv was spreading were studied. with plants of susceptible pea cv. kaspa, the transmission efficiencies of aphis craccivora, myzus persicae, acyrthosiphon kondoi and rhopalosiphum padi were 27%, 26%, 6% and 3%, respectively. lipaphis erysimi did not tran ...201728408208
seed treatments with thiamine reduce the performance of generalist and specialist aphids on crop plants.thiamine is a vitamin that has been shown to act as a trigger to activate plant defence and reduce pathogen and nematode infection as well as aphid settling and reproduction. we have here investigated whether thiamine treatments of seeds (i.e. seed dressing) would increase plant resistance against aphids and whether this would have different effects on a generalist than on specialist aphids. seeds of wheat, barley, oat and pea were treated with thiamine alone or in combination with the biocontro ...201728578733
insect deterrent and nematicidal screening of microfungi from mexico and anti-aphid compounds from gliomastix masseei.fungal metabolites are promising alternatives for the development of biorational pesticides. in this sense, microfungi from tropical regions are valuable sources of natural compounds for pest management. with the aim of broadening the search for new eco-friendly products to manage plant pests, this study was carried out to evaluate the biological activity of 23 tropical fungal extracts on three species of phytophagous insects and a plant parasitic nematode. in addition, the active principles of ...201728258772
dahurelmusin a, a hybrid peptide-polyketide from elymus dahuricus infected by the epichloë bromicola endophyte.one novel hybrid peptide-polyketide, dahurelmusin a (1), was isolated from elymus dahuricus infected by the epichloë bromicola endophyte. comprehensive spectroscopic analysis revealed that 1 is the first example of hybrid peptide-polyketide possessing an unprecedented 5-hydroxy-2,2,4,6-tetramethyl-3-oxooctanoic acid moiety. the single-crystal x-ray diffraction analyses allowed the absolute configuration assignment of this compound. compound 1 also exhibited significant insecticidal activities ag ...201728029264
contribution of noncolonizing aphids to potato virus y prevalence in potato in idaho.potato virus y (pvy) is a major concern for potato production in the united states given its impact on both crop quality and yield. although green peach aphid, myzus persicae (sulzer), is the most efficient pvy vector, it may be less abundant in potato-growing areas of idaho relative to non-potato-colonizing aphid vectors of pvy that may disperse from nearby cereal fields and other crops. a field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fi ...201628028092
contribution of noncolonizing aphids to potato virus y prevalence in potato in idaho.potato virus y (pvy) is a major concern for potato production in the united states given its impact on both crop quality and yield. although green peach aphid, myzus persicae (sulzer), is the most efficient pvy vector, it may be less abundant in potato-growing areas of idaho relative to non-potato-colonizing aphid vectors of pvy that may disperse from nearby cereal fields and other crops. a field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fi ...201627694432
long chain alcohols produced by trichoderma citrinoviride have phagodeterrent activity against the bird cherry-oat aphid rhopalosiphum padi.in this study we report the effects of fungal metabolites isolated from cultures of the fungus trichoderma citrinoviride item 4484 on the feeding preference of the aphid rhopalosiphum padi, a major pest of cereal crops. different phagodeterrent metabolites were purified by a combination of direct and reverse phase column chromatography and thin-layer chromatography. chemical investigations, by spectroscopic and chemical methods, led to the identification of different long chain primary alcohols ...201627014220
molecular cloning, expression pattern of multidrug resistance associated protein 1 (mrp1, abcc1) gene, and the synergistic effects of verapamil on toxicity of two insecticides in the bird cherry-oat aphid.the atp-binding cassette (abc) transporters are important transmembrane proteins encoded by a supergene family. the majority of abc proteins are primary active transporters that bind and hydrolyze atp to mediate the efflux of a diverse range of substrates across lipid membranes. in this study, we cloned and characterized a putative multidrug resistance associated protein 1 (mrp1) from rhopalosiphum padi encoded by abcc1. structural analysis showed that this protein has structural features typica ...201627110952
molecular cloning, expression pattern and polymorphisms of nadph-cytochrome p450 reductase in the bird cherry-oat aphid rhopalosiphum padi (l.).nadph-cytochrome p450 reductase (cpr) plays an important role in the cytochrome p450 (cyp)-mediated metabolism of endogenous and exogenous substrates. cpr has been found to be associated with insecticide metabolism and resistance in many insects. however, information regarding cpr in the bird cherry-oat aphid, rhopalosiphum padi, is unavailable. in the current study, a full-length cdna (2,476 bp) of cpr (rpcpr) encoding 681 amino acids was cloned from r. padi. nucleotide sequence and deduced ami ...201627124302
triticum monococcum lines with distinct metabolic phenotypes and phloem-based partial resistance to the bird cherry-oat aphid rhopalosiphum padi.crop protection is an integral part of establishing food security, by protecting the yield potential of crops. cereal aphids cause yield losses by direct damage and transmission of viruses. some wild relatives of wheat show resistance to aphids but the mechanisms remain unresolved. in order to elucidate the location of the partial resistance to the bird cherry-oat aphid, rhopalosiphum padi, in diploid wheat lines of triticum monococcum, we conducted aphid performance studies using developmental ...201627570248
expression patterns of genes involved in ascorbate-glutathione cycle in aphid-infested maize (zea mays l.) seedlings.reduced forms of ascorbate (asa) and glutathione (gsh) are among the most important non-enzymatic foliar antioxidants in maize (zea mays l.). the survey was aimed to evaluate impact of bird cherry-oat aphid (rhopalosiphum padi l.) or grain aphid (sitobion avenae f.) herbivory on expression of genes related to ascorbate-glutathione (asa-gsh) cycle in seedlings of six maize varieties (ambrozja, nana, tasty sweet, touran, waza, złota karłowa), differing in resistance to the cereal aphids. relative ...201626907270
expression patterns, mutation detection and rna interference of rhopalosiphum padi voltage-gated sodium channel genes.the voltage-gated sodium channel (vgsc) is the target of sodium-channel-blocking insecticides. traditionally, animals were thought to have only one vgsc gene comprising a α-subunit with four homologous domains (di-div). the present study showed that rhopalosiphum padi, an economically important crop pest, owned a unique heterodimeric vgsc (h1 and h2 subunits) encoded by two genes (rpvgsc1 and rpvgsc2), which is unusual in insects and other animals. the open reading frame (orf) of rpvgsc1 consist ...201627439594
cloning of eight rhopalosiphum padi (hemiptera: aphididae) nachr subunit genes and mutation detection of the β1 subunit in field samples from china.the bird cherry-oat aphid, rhopalosiphum padi (l.), is one of the most important wheat pests. this aphid damages through direct feeding and by transmitting the barley yellow dwarf virus (bydv). both types of damage significantly reduce the quality and yield of wheat crops globally. insecticides are the primary method of controlling the bird cherry-oat aphid in china, yet this aphid species has developed resistance to different types of insecticides, especially organophosphates and carbamates. in ...201627521918
virus infection mediates the effects of elevated co2 on plants and vectors.atmospheric carbon dioxide (co2) concentration has increased significantly and is projected to double by 2100. to increase current food production levels, understanding how pests and diseases respond to future climate driven by increasing co2 is imperative. we investigated the effects of elevated co2 (eco2) on the interactions among wheat (cv. yitpi), barley yellow dwarf virus and an important pest and virus vector, the bird cherry-oat aphid (rhopalosiphum padi), by examining aphid life history, ...201626941044
interactions between metopolophium festucae cerealium (hemiptera: aphididae) and barley yellow dwarf virus (bydv-pav).interactions between an invasive aphid, metopolophium festucae (theobald) subsp. cerealium, and barley yellow dwarf virus (bydv-pav) were studied under laboratory conditions. m. festucae cerealium is an economic pest of wheat and barley that has recently been found in high population densities in wheat in the pacific northwest of the united states. bydv-pav is the most prevalent and injurious species of bydv worldwide and in the pacific northwest. although m. festucae sensu stricto (theobald 191 ...201626896673
inter-varietal interactions among plants in genotypically diverse mixtures tend to decrease herbivore performance.much research has explored the effects of plant species diversity on herbivore populations, but far less has considered effects of plant genotypic diversity, or how abiotic stressors, like drought, can modify effects. mechanisms by which plant genotypic diversity affects herbivore populations remain largely unresolved. we used greenhouse studies with a model system of wheat (triticum aestivum l.) and bird cherry-oat aphid (rhopalosiphum padi l.) to determine whether the genotypic diversity of a ...201627170329
deciphering the role of nadph oxidase in complex interactions between maize (zea mays l.) genotypes and cereal aphids.plant nadph oxidases (noxs) encompass a group of membrane-bound enzymes participating in formation of reactive oxygen species (ros) under physiological conditions as well as in response to environmental stressors. the purpose of the survey was to unveil the role of nadph oxidase in pro-oxidative responses of maize (zea mays l.) seedling leaves exposed to cereal aphids' infestation. the impact of apteral females of bird cherry-oat aphid (rhopalosiphum padi l.) and grain aphid (sitobion avenae f.) ...201627178208
impact of change in winter strategy of one parasitoid species on the diversity and function of a guild of parasitoids.the rise of temperatures may enable species to increase their activities during winter periods and to occupy new areas. in winter, resource density is low for most species and an increased number of active consumers during this season may produce heightened competitive pressure. in western france, the aphid parasitoid species aphidius avenae haliday has been known to adopt a winter diapausing strategy adjacent to newly sown cereal crops, until recent reports of active winter populations in cerea ...201626558625
comparative transcriptomics and proteomics of three different aphid species identifies core and diverse effector sets.aphids are phloem-feeding insects that cause significant economic losses to agriculture worldwide. while feeding and probing these insects deliver molecules, called effectors, inside their host to enable infestation. the identification and characterization of these effectors from different species that vary in their host range is an important step in understanding the infestation success of aphids and aphid host range variation. this study employs a multi-disciplinary approach based on transcrip ...201626935069
application of rna-seq for mitogenome reconstruction, and reconsideration of long-branch artifacts in hemiptera phylogeny.hemiptera make up the largest nonholometabolan insect assemblage. despite previous efforts to elucidate phylogeny within this group, relationships among the major sub-lineages remain uncertain. in particular, mitochondrial genome (mitogenome) data are still sparse for many important hemipteran insect groups. recent mitogenomic analyses of hemiptera have usually included no more than 50 species, with conflicting hypotheses presented. here, we determined the nearly complete nucleotide sequence of ...201627633117
sublethal effects of imidacloprid on the fecundity, longevity, and enzyme activity of sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus).the aphid species sitobion avenae and rhopalosiphum padi are the most important pests in wheat growing regions of many countries. in this study, we investigated the sublethal effects of imidacloprid on fecundity, longevity, and enzyme activity in both aphid species by comparing 3-h exposure for one or three generations. our results indicated that 3-h exposure to sublethal doses of imidacloprid for one generation had no discernible effect on the survival, fecundity, longevity, or enzyme activity ...201627161277
influence of selected plant amines on probing behaviour of bird cherry-oat aphid (rhopalosiphum padi l.).the study aimed to quantify the influence of common plant polyamines and tyramine on probing behaviour in the bird cherry-oat aphid (rhopalosiphum padi l.). electrical penetration graphs (dc) were used to monitor the probing and feeding behaviour of r. padi exposed to the amines agmatine, cadaverine, putrescine, spermidine, spermine and tyramine. the study results showed that the analyzed amines tended to shorten the stylet activity of aphids in the gels (as indicated by the g-c pattern), prolon ...201626898153
categorization of putative factors against rhopalosiphum padi (l.) (heteroptera: aphididae).the bird cherry-oat aphid, rhopalosiphum padi (l.) (heteroptera: aphididae), causes heavy losses to wheat crops worldwide by direct damage and virus transmission. this study was conducted to identify putative resistance mechanisms in four wheat varieties (bobtail, ladd, stephens, and skiles) and one advanced line (ys434)where r. padi was subjected to choice and no-choice tests. antixenosis, antibiosis and tolerance studies were conducted in controlled environmental conditions at temperature of 2 ...201626568060
longitudinal clines in the frequency distribution of 'super-clones' in an aphid crop pest.parthenogenesis is the main mode of reproduction of aphids. their populations are therefore composed of clones whose frequency distribution varies in space and time. previous population genetic studies on aphids have highlighted the existence of highly abundant clones ('super-clones'), distributed over large geographic areas and persisting over time. whether the abundance of 'super-clones' results from their ecological success or from stochastic forces, such as drift and migration, is an open qu ...201526278064
identification of rhopalosiphum padi virus 5' untranslated region sequences required for cryptic promoter activity and internal ribosome entry.the 579-nucleotide 5' untranslated region (5'utr) of the rhopalosiphum padi virus (rhpv) possesses a cross-kingdom internal ribosome entry site (ires) activity that functions in insect, mammalian, and plant-derived in vitro translation systems, and six taag motifs within the dna fragment encoding the rhpv 5'utr were previously found to confer the rhpv 5'utr with late promoter activity in baculovirus. in the present study, various truncated rhpv 5'utr sequences were produced, and among them, a fr ...201526184188
aphidophagous parasitoids can forage wheat crops before aphid infestation, parana state, brazil.aphid parasitoids are common in brazilian wheat fields, and parasitize aphids at the wheat tillering stage. however, there is little information available about when this natural enemy occurs in wheat crops. this study investigated the initial occurrence of aphid parasitoids in four commercial wheat crops in northern paraná during the 2009 crop season. we installed two malaise traps at each wheat farm, and 400 tillers were assessed weekly in each field for aphid abundance. during this study, we ...201525843593
gene silencing of two acetylcholinesterases reveals their cholinergic and non-cholinergic functions in rhopalosiphum padi and sitobion avenae.the function of acetylcholinesterase (ache) is to terminate synaptic transmission by hydrolysing the neurotransmitter acetylcholine (ach) in the synaptic cleft, and thus it is an effective target for organophosphate (op) and carbamate (cb) insecticides.201524729410
tritrophic interactions between parasitoids and cereal aphids are mediated by nitrogen fertilizer.host plant nutritional quality can directly and indirectly affect the third trophic levels. the aphid-parasitoid relationship provides an ideal system to investigate tritrophic interactions (as the parasitoids are completely dependent for their development upon their hosts) and assess the bottom up forces operating at different concentrations of nitrogen applications. the effects of varying nitrogen fertilizer on the performance of aphidius colemani (v.) reared on sitobion avenae (f.) and aphidi ...201524623663
testing the fecundity advantage hypothesis with sitobion avenae, rhopalosiphum padi, and schizaphis graminum (hemiptera: aphididae) feeding on ten wheat accessions.the fecundity advantage hypothesis suggests that females with a large body size produce more offspring than smaller females. we tested this hypothesis by exploring the correlations between life-history traits of three aphid species feeding on ten wheat accessions at three levels of analysis with respect to the host plant: overall, inter-accession, and intra-accession. we found that fecundity was significantly correlated with mean relative growth rate (mrgr), weight gain, and development time, an ...201526680508
the effect of pro-ecological procedures and insect foraging on the total content of phenol compounds in winter wheat.in laboratory conditions, the effect of pro-ecological procedures (application of effective microorganisms and asahi sl biostimulator) and foraging by insects [cereal leaf beetle (oulema melanopa l.) and bird cherry-oat aphid (rhopalosiphum padi (l.)] on the total content of phenolic compounds in winter wheat, was studied. correlations between the total content of phenolic compounds (determined by the folin-ciocalteau colorimetric method) expressed as the amount of pyrogallol in wheat plants: un ...201526081273
hydroxamic acids in secale cereale l. and the relationship with their antifeedant and allelopathic properties.contents of the hydroxamic acids 2,4-dihydroxy-1,4-benzoxazin-3-one (diboa), and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (dimboa) in leaves and roots of 14 cultivars of rye, secale cereale l., were determined. dynamics of accumulation in three cultivars were evaluated. diboa was the main cyclic hydroxamic acid in leaves but the contents differed significantly between the cultivars. both diboa and dimboa were present in the roots. maximum concentration of diboa in leaves and dimboa in roots ...201517137112
increased susceptibility to aphids of flowering wheat plants exposed to low temperatures.frost is known to directly affect flowering wheat plants (triticum aestivum l.) and lead to reduced grain yield. additionally, it may increase wheat susceptibility to economically important pests, such as aphids (hemiptera: aphididae). wheat plants at flowering stage were exposed to one of the three temperature treatments: ambient (11-12°c), 0°c, and -3°c for 60 min. preference (3-choice) and performance (no-choice) bioassays with aphids (rhopalosiphum padi l.) were conducted 1, 3, 6, and 12 d a ...201526313967
assessment of sublethal and transgenerational effects of pirimicarb on the wheat aphids rhopalosiphum padi and sitobion avenae.the wheat aphids, rhopalosiphum padi (linnaeus) and sitobion avenae (fabricius), are key pests on wheat crops worldwide. management practices rely primarily on insecticides. the pirimicarb (carbamate) is used extensively as an effective insecticide to control these two aphids. in addition to the mortality caused by pirimicarb, various sublethal effects may occur in aphids when exposed to low lethal or sublethal doses. understanding the general effect of pirimicarb on aphids could help increasing ...201526121265
risk assessment of genetically engineered maize resistant to diabrotica spp.: influence on above-ground arthropods in the czech republic.transgenic maize mon88017, expressing the cry3bb1 toxin from bacillus thuringiensis (bt maize), confers resistance to corn rootworms (diabrotica spp.) and provides tolerance to the herbicide glyphosate. however, prior to commercialization, substantial assessment of potential effects on non-target organisms within agroecosystems is required. the mon88017 event was therefore evaluated under field conditions in southern bohemia in 2009-2011, to detect possible impacts on the above-ground arthropod ...201526083254
integrative proteomics to understand the transmission mechanism of barley yellow dwarf virus-gpv by its insect vector rhopalosiphum padi.barley yellow dwarf virus-gpv (bydv-gpv) is transmitted by rhopalosiphum padi and schizaphis graminum in a persistent nonpropagative manner. to improve our understanding of its transmission mechanism by aphid vectors, we used two approaches, isobaric tags for relative and absolute quantitation (itraq) and yeast two-hybrid (yth) system, to identify proteins in r. padi that may interact with or direct the spread of bydv-gpv along the circulative transmission pathway. thirty-three differential aphi ...201526161807
landing preference and reproduction of rhopalosiphum padi (hemiptera: aphididae) in the laboratory on three maize, potato, and wheat cultivars.the bird cherry-oat aphid rhopalosiphum padi (l.) transmits the nonpersistent potato virus y (pvy) to seed potatoes. planting a nonvirus host plant around the main crop can reduce pvy incidence, because aphids tend to land in high numbers at the edge of a field and the crop border acts as a virus sink. this study determined r. padi landing and settling preferences and reproductive rates on three cultivars each of maize and wheat compared with potato in the laboratory as a basis for identifying a ...201526022628
effect of insecticide-treated potato plants on aphid behavior and potato virus y acquisition.the objective was to assess the effect of two contact insecticides, lambda-cyhalothrin and flonicamid, and three systemic insecticides, pymetrozine, dimethoate and imidacloprid, on the behavior and potato virus y (pvy) acquisition of three aphid species, macrosiphum euphorbiae (thomas), rhopalosiphum padi l. and aphis fabae (scopoli).201525159012
[anticholinesterase effect of organophosphorus and pyrethroid insecticides on some phytophages, their predators, and parasites].the normal catalytic activity of insects cholinesterases was determined: apanteles glomeratus l., coccinella septempunctata l., rhopalosiphum padi l. and pieris brassicae l. constants of bimolecular interaction of three insecticides for insects were calculated: cholinesterase of c. septempunctata were the most sensitive to bi-58 new [kii = (4.54 +/- 0.23). 10(4)], cholinesterase of aphids was revealed to be the most sensitive to acetec [kii = (2.9 +/- 0.14). 10(5)]. the studies have been carried ...201510609334
mechanism of entomotoxicity of the concanavalin a in rhopalosiphum padi (hemiptera: aphididae).the toxicity effect of concanavalin a (canavalia ensiformis lectin, cona) to bird cherry-oat aphid, rhopalosiphum padi l. (hemiptera: aphididae), was investigated in the laboratory by using artificial diets containing cona concentrations. bird cherry-oat aphid performance was affected by the presence of con a in artificial diets. the lectin added into the liquid diet increased the prereproductive period, mortality, and the average time of generation development (t) and decreased fecundity and th ...201425525100
activities of glutathione s-transferase and glutathione peroxidases related to diet quality in an aphid predator, the seven-spot ladybird, coccinella septempunctata l. (coleoptera: coccinellidae(.larvae of coccinella septempunctata were reared on three aphid diets, consisting of pure rhopalosiphum padi, pure metopolophium dirhodum, and an equal mix of these aphid species. in the pupal stage, the activities of three detoxifying enzyme systems - glutathione s-transferase (gst) with 1-chloro-2,4-dinitrobenzene as substrate, glutathione peroxidase with hydrogen peroxide as substrate (gsh-px[h2o2]), and glutathione peroxidase with tert-butyl hydroperoxide as substrate (gsh-px[tbh]) - were ass ...201425419924
evaluation of tetraploid switchgrass (poales: poaceae) populations for host suitability and differential resistance to four cereal aphids.switchgrass, panicum virgatum l., is being developed as a bioenergy feedstock. the potential for large-scale production has encouraged its evaluation as a host for important grass pests. eight no-choice studies were performed for two developmental stages of two switchgrass cultivars ('kanlow' and'summer') and two experimental strains, k x s, and s x k produced by reciprocal mating of these cultivars followed by selection for high yield. plants were evaluated for host suitability and damage diffe ...201424665729
analysis of new aphid lethal paralysis virus (alpv) isolates suggests evolution of two alpv species.aphid lethal paralysis virus (alpv; family dicistroviridae) was first isolated from the bird cherry-oat aphid, rhopalosiphum padi. alpv-like virus sequences have been reported from many insects and insect predators. we identified a new isolate of alpv (alpv-ap) from the pea aphid, acyrthosiphon pisum, and a new isolate (alpv-dvv) from western corn rootworm, diabrotica virgifera virgifera. alpv-ap has an ssrna genome of 9940 nt. based on phylogenetic analysis, alpv-ap was closely related to alpv- ...201425170050
toxin delivery by the coat protein of an aphid-vectored plant virus provides plant resistance to aphids.the sap-sucking insects (order hemiptera), including aphids, planthoppers, whiteflies and stink bugs, present one of the greatest challenges for pest management in global agriculture. insect neurotoxins offer an alternative to chemical insecticides for controlling these pests, but require delivery into the insect hemocoel. here we use the coat protein of a luteovirus, an aphid-vectored plant virus, to deliver a spider-derived, insect-specific toxin that acts within the hemocoel. the luteovirid c ...201424316580
preference by a virus vector for infected plants is reversed after virus acquisition.pathogens and their vectors can interact either directly or indirectly via their shared hosts, with implications for the persistence and spread of the pathogen in host populations. for example, some plant viruses induce changes in host plants that cause the aphids that carry these viruses to settle preferentially on infected plants. furthermore, relative preference by the vector for infected plants can change to a preference for noninfected plants after virus acquisition by the vector, as has re ...201424269348
the role of natural enemy foraging guilds in controlling cereal aphids in michigan wheat.insect natural enemies (predators and parasitoids) provide important ecosystem services by suppressing populations of insect pests in many agricultural crops. however, the role of natural enemies against cereal aphids in michigan winter wheat (triticum aestivum l.) is largely unknown. the objectives of this research were to characterize the natural enemy community in wheat fields and evaluate the role of different natural enemy foraging guilds (foliar-foraging versus ground-dwelling predators) i ...201425473951
mapping resistance to the bird cherry-oat aphid and the greenbug in wheat using sequence-based genotyping.identification of novel resistance qtl against wheat aphids. first qtl-resistance report for r. padi in wheat and chromosome 2dl for s. graminum . these sources have potential use in wheat breeding. the aphids rhopalosiphum padi and schizaphis graminum are important pests of common wheat (triticum aestivum l.). characterization of the genetic bases of resistance sources is crucial to facilitate the development of resistant wheat cultivars to these insects. we examined 140 recombinant inbred line ...201425112202
contribution of predator identity to the suppression of herbivores by a diverse predator assemblage.studies manipulating predator diversity and measuring the impact on herbivore abundance have found that enhancing predator species richness often increases the strength of prey suppression. this relationship may be due to mechanisms such as complementarity or facilitation, which are considered "true" benefits of diversity because greater prey suppression is an emergent property of the multispecies predator community. or it may be due to an identity effect, an "apparent" benefit of diversity that ...201424755243
epichloë endophytes alter inducible indirect defences in host grasses.epichloë endophytes are common symbionts living asymptomatically in pooid grasses and may provide chemical defences against herbivorous insects. while the mechanisms underlying these fungal defences have been well studied, it remains unknown whether endophyte presence affects the host's own defences. we addressed this issue by examining variation in the impact of epichloë on constitutive and herbivore-induced emissions of volatile organic compounds (voc), a well-known indirect plant defence, bet ...201424978701
valorization of essential oils from moroccan aromatic plants.the chemical composition and biological activity of cultivated and wild medicinal and aromatic plants from morocco (artemisia herba-alba, lippia citriodora, mentha pulegium, m. spicata, myrtus communis, rosmarinus officinalis, and thymus satureioides) are described. the essential oils (eos) of these species have been analyzed by gc-ms. the antifeedant, nematicidal and phytotoxic activities of the eos were tested on insect pests (spodoptera littoralis, myzus persicae and rhopalosiphum padi), root ...201425233584
genes involved in barley yellow dwarf virus resistance of maize.the results of our study suggest that genes involved in general resistance mechanisms of plants contribute to variation of bydv resistance in maize. with increasing winter temperatures in europe, barley yellow dwarf virus (bydv) is expected to become a prominent problem in maize cultivation. breeding for resistance is the best strategy to control the disease and break the transmission cycle of the virus. the objectives of our study were (1) to determine genetic variation with respect to bydv res ...201425261982
sequencing and validation of reference genes to analyze endogenous gene expression and quantify yellow dwarf viruses using rt-qpcr in viruliferous rhopalosiphum padi.the bird cherry-oat aphid (rhopalosiphum padi), an important pest of cereal crops, not only directly sucks sap from plants, but also transmits a number of plant viruses, collectively the yellow dwarf viruses (ydvs). for quantifying changes in gene expression in vector aphids, reverse transcription-quantitative polymerase chain reaction (rt-qpcr) is a touchstone method, but the selection and validation of housekeeping genes (hkgs) as reference genes to normalize the expression level of endogenous ...201424810421
could behaviour and not physiological thermal tolerance determine winter survival of aphids in cereal fields?traits of physiological thermotolerance are commonly measured in the laboratory as predictors of the field success of ectotherms at unfavourable temperatures (e.g. during harsh winters, heatwaves, or under conditions of predicted global warming). due to being more complicated to measure, behavioural thermoregulation is less commonly studied, although both physiology and behaviour interact to explain the survival of ectotherms. the aphids metopolophium dirhodum, rhopalosiphum padi and sitobion av ...201425490555
expression profiling of selected glutathione transferase genes in zea mays (l.) seedlings infested with cereal aphids.the purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (zea mays l.) varieties (relatively resistant ambrozja and susceptible tasty sweet) that were colonized with oligophagous bird cherry-oat aphid (rhopalosiphum padi l.) or monophagous grain aphid (sitobion avenae l.). simultaneously, insect-triggered generation of superoxide anion radicals (o2•-) in infested z. mays plants was moni ...201425365518
differential expression of superoxide dismutase genes in aphid-stressed maize (zea mays l.) seedlings.the aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodb) in seedling leaves of the zea mays l. tasty sweet (susceptible) and ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous sitobion avenae f. (grain aphid) or oligophagous rhopalosiphum padi l. (bird cherry-oat aphid). secondarily, aphid-elicited alternations in the antioxidative capacity towards dpph (1,1-diphenyl-2-picrylhyd ...201424722734
a negative effect of a pathogen on its vector? a plant pathogen increases the vulnerability of its vector to attack by natural enemies.plant pathogens that are dependent on arthropod vectors for transmission from host to host may enhance their own success by promoting vector survival and/or performance. the effect of pathogens on vectors may be direct or indirect, with indirect effects mediated by increases in host quality or reductions in the vulnerability of vectors to natural enemies. we investigated whether the bird cherry-oat aphid rhopalosiphum padi, a vector of cereal yellow dwarf virus (cydv) in wheat, experiences a red ...201424322446
effect of plant nutrition on aphid size, prey consumption, and life history characteristics of green lacewing.plant quality can directly and indirectly affect the third trophic level. the predation by all the instars of green lacewing, chrysoperla carnea (s.) (neuroptera: chrysopidae) on the cereal aphids, rhopalosiphum padi (l.), and sitobion avenae (f.) at varying nitrogen fertilizer levels was calculated under laboratory conditions. wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the c. carnea. aphid densities of 10, 3 ...201423956127
comparative studies on acetylcholinesterase characteristics between the aphids, sitobion avenae and rhopalosiphum padi.the aphids sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) (hemiptera: aphidiae) are serious pests on grain crops and usually coexist on late period of wheat growth in china. bioassays showed that r. padi was more susceptible than s. avenae to pirimicarb that is used for wheat aphid control, and the determination of acetylcholinesterase (ache, ec 3.1.1.7) sensitivity showed that the sensitivity of ache to pirimicarb was significantly higher in r. padi than in s. avenae ( lu and gao ...201323879406
the resistance and correlation analysis to three species of cereal aphids (hemiptera: aphididae) on 10 wheat varieties or lines.winter wheat resistance is an efficient and environmentally friendly means to controlling aphids. by using principal component analysis and correlation analysis, we evaluated the resistance of 10 winter wheat varieties or lines from three countries to the following three aphid species: sitobion avenae, rhopalosiphum padi, and schizaphis graminum. the data show that batis was susceptible to si. avenae and r. padi, but had adverse effect on the development of sc. graminum; astron was advantageous ...201324020308
exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15)n labelling.studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen ((15)n). we combined the electrical penetration graph (epg) technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (irms) to precisely measure the uptake of nitrogen. bir ...201324376642
virulence of verticillium lecanii (z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?entomopathogenic fungi such as verticillium lecanii (z.) (mycotal(®)) are used for pest control as an alternative to chemical control. in this study, the effect of v. lecanii on cereal aphids is assessed. in addition, an investigation is carried out to determine whether the use of v. lecanii affects the performance of two natural enemies of aphids, the predator harmonia axyridis (p.) and the parasitoid aphidius colemani (v.), in no-choice experiments under laboratory conditions.201322945885
terpenes and polyacetylenes from cultivated artemisia granatensis boiss (royal chamomile) and their defensive properties.artemisia granatensis, an endemic endangered plant species from sierra nevada (spain) has been successfully cultivated in artificial systems (plants in artificial soil and transformed in vitro roots) to generate enough plant biomass (aerial and root) to allow for its chemical and biological study and at the same time to provide with methods for the sustainable production of the plant and its metabolites. a eudesmanolide (17) along with six sesquiterpenes (11-16), nine monoterpenes (2-10), one no ...201323642456
peramine and lolitrem b from endophyte-grass associations cascade up the food chain.endophytic fungi in cool-season grass species produce herbivore-toxic alkaloids, which are assumed to harm higher trophic levels along food chains. previous studies have shown fitness disadvantages for higher trophic levels that feed on aphids that were exclusively reared on perennial ryegrass (lolium perenne) infected with the endophytic fungus neotyphodium lolii. however, it is unknown whether the alkaloids produced by the fungus-grass association can be assimilated by plant sap-sucking insect ...201324233445
analysis of the activity of virus internal ribosome entry site in silkworm bombyx mori.internal ribosome entry site (ires) has been widely used in genetic engineering; however, the application in silkworm (bombyx mori) has hardly been reported. in this study, the biological activity of partial sequence of encephalomyocarditis virus (emcv) ires, rhopalosiphum padi virus (rhpv) ires, and the hybrid of ires of emcv and rhpv were investigated in spodoptera frugiperda (sf9) cell line and silkworm tissues. the hybrid ires of emcv and rhpv showed more effective than emcv ires or rhpv ire ...201323644592
distribution of barley yellow dwarf virus-pav in the sub-antarctic kerguelen islands and characterization of two new luteovirus species.a systematic search for viral infection was performed in the isolated kerguelen islands, using a range of polyvalent genus-specific pcr assays. barley yellow dwarf virus (bydv) was detected in both introduced and native grasses such as poa cookii. the geographical distribution of bydv and its prevalence in p. cookii were analyzed using samples collected from various sites of the archipelago. we estimate the average prevalence of bydv to be 24.9% in p. cookii, with significant variability between ...201323825645
population growth and damage caused by rhopalosiphum padi (l.) (hemiptera, aphididae) on different cultivars and phenological stages of wheat.among the aphids associated with wheat and other winter cereals, rhopalosiphum padi (l.) is currently the predominant species in the wheat growing region of southern brazil. the damage caused by this aphid occurs by direct feeding and/or by the transmission of pathogenic viruses, such as the barley/cereal yellow dwarf virus. in order to estimate the direct damage caused by r. padi on wheat, we evaluated the population growth of this aphid during the tillering and elongation stages and its effect ...201327023210
thiamine treatments alleviate aphid infestations in barley and pea.treatment of plants with thiamine (vitamin b1) has before been shown to activate plant defence against microorganisms. here, we have studied the effects of thiamine treatments of plants on aphid reproduction and behaviour. the work was mainly carried out with bird cherry-oat aphid (rhopalosiphum padi l.) on barley (hordeum vulgare l.). aphid population growth and aphid acceptance on plants grown from seeds soaked in a 150μm thiamine solution were reduced to ca. 60% of that on control plants. r. ...201323787153
colonization of the biomass energy crop miscanthus by the three aphid species, aphis fabae, myzus persicae, and rhopalosiphum padi.miscanthus is a perennial c4-grass that has received much interest as a potential of impact on the local agroecosytem. in this context, laboratory experiments were conducted to investigate the potential colonization of this new exotic plant species by three of the main aphid pest species of common crops in picardie, northern france. in host preference experiments, the two polyphagous aphid species studied, aphis fabae (scop) and myzus persicae (sulzer), exhibited an xclusive preference for their ...201323786055
seasonal phenology and species composition of the aphid fauna in a northern crop production area.the species diversity of aphids and seasonal timing of their flight activity can have significant impacts on crop production, as aphid species differ in their ability to transmit plant viruses and flight timing affects virus epidemiology. the aim of the study was to characterise the species composition and phenology of aphid fauna in finland in one of the northernmost intensive crop production areas of the world (latitude 64°).201323967149
population dynamics of three aphid species (hemiptera: aphididae) on four ipomoea spp. infected or noninfected with sweetpotato potyviruses.three aphid species, aphis gossypii glover and myzus persicae (sulzer) (efficient sweetpotato potyvirus vectors) and rhopalosiphum padi (l.) (an inefficient vector), are commonly found in sweet potato, ipomoea batatas (l.), in louisiana. field-grown sweet potatoes are naturally infected with several potyviruses: sweet potato feathery mottle virus, sweet potato virus g, and sweet potato virus 2. thus, these aphids commonly encounter virus-infected hosts. what is not known is how each of these aph ...201324020267
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