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two distinct mechanisms regulate luteovirus transmission efficiency and specificity at the aphid salivary gland.barley yellow dwarf luteovirus (bydv) particles are transmitted by aphids in a species-specific manner. transmission to plants requires that the virus particles be transported across the basal lamina and plasmalemma of the accessory salivary gland (asg). to characterize the role of the asg basal lamina in regulating bydv transmission, five aphid species were microinjected with purified new york isolates bydv-pav or -rpv. both viruses associated specifically only with the asg basal lamina. the ab ...19979049397
vector specificity of barley yellow dwarf virus (bydv) transmission: identification of potential cellular receptors binding bydv-mav in the aphid, sitobion avenae.two proteins (sam35 and sam50) isolated from head tissues of the aphid vector, sitobion avenae, were identified as potential receptors for barley yellow dwarf virus mav isolate (luteoviridae) based on mav virus overlay assays and immunoblots of urea sds 2-d gels. an anti-idiotypic antibody (mav4 anti-id) that mimics an epitope on mav virions and competes with mav in antibody binding assays also bound to sam50 and sam35 and to six additional proteins including a groel homolog. no mav-binding prot ...200111448166
[niches analysis of three aphid populations on spring sowing maize].systematic analysis of aphid populations and niches patterns on spring sowing maize was carried out during 1998-1999 in the suburbs of chongqing. the results indicated that there were three aphid populations rhopalosiphum maidis fitch., rhopalosiphum padi linn. and sitobion avenae fabricius distributed on the spring sowing maize. the mixed aphid populations traded off during the growth period of spring sowing maize, and two peaks of quantitative counts were shown at the mid and last ten days of ...200314733003
estimation of hymenopteran parasitism in cereal aphids by using molecular markers.polymerase chain reaction (pcr) primers were designed and tested for identification of immature parasitoids in small grain cereal aphids and for estimation of parasitism rates. pcr technique was evaluated for 1) greenhouse-reared greenbugs, schizaphis graminum (rondani), parasitized by lysiphlebus testaceipes cresson and 2) aphids collected from winter wheat fields in caddo county, oklahoma. for greenhouse samples, parasitism frequencies for greenbugs examined by pcr at 0, 24, and 48 h after rem ...200515765686
aphid (hemiptera: aphididae) species composition and potential aphid vectors of plum pox virus in pennsylvania peach orchards.plum pox, an invasive disease recently identified in pennsylvania stone fruit orchards, is caused by the aphid-transmitted plum pox virus (genus potyvirus, family potyviridae, ppv). to identify potential vectors, we described the aphid species communities and the seasonal dynamics of the dominant aphid species within pennsylvania peach orchards. aphids were trapped weekly in 2002 and 2003 from mid-april through mid-november within two central pennsylvania orchards by using yellow and green water ...200516334309
changes in delta 13c stable isotopes in multiple tissues of insect predators fed isotopically distinct prey.traditionally, researchers have used measurements of carbon stable isotopes to infer the composition of consumers' diets. however, since consumer's tissues may process carbon isotopes differently, particularly following a diet shift, it is possible to use measurements of carbon isotopes in multiple tissues to determine not only the composition of an individual's diet, but also the temporal dynamics thereof. this study examined how stable isotopes of carbon (13c/12c, expressed as delta 13c) chang ...200616341886
enhancement of resistance to aphids by introducing the snowdrop lectin gene gna into maize plants.in order to enhance the resistance to pests, transgenic maize (zea mays l.) plants from elite inbred lines containing the gene encoding snowdrop lectin (galanthus nivalis l. agglutinin; gna) under control of a phloem-specific promoter were generated through the agrobacterium tumefaciens-mediated method. the toxicity of gna-expressing plants to aphids has also been studied. the independently derived plants were subjected to molecular analyses. polymerase chain reaction (pcr) and southern blot ana ...200516388137
influence of aphid species and barley yellow dwarf virus on soft red winter wheat yield.yield loss in soft red winter wheat, triticum aestivum l., caused by aphid-transmitted barley yellow dwarf virus (family luteoviridae, genus luteovirus, bydv) was measured over a 2-yr period in central missouri. rhopalosiphum padi (l.) was the most common and economically important species, accounting for > 90% of the total aphids. schizaphis graminum (rondani), rhopalosiphum maidis (fitch), and sitobion avenae (f.) made up the remainder of the aphids. aphid numbers peaked at wheat stem elongati ...200516539127
[effects of transgenic corn expressing bacillus thuringiensis cry1ab toxin on population increase of rhopalosiphum maidis fitch].a laboratory study was made on the effects of transgenic corn expressing cry1ab toxin from the bacterium bacillus thuringiensis (bt) on the life table of an experimental population of corn leaf aphid rhopalosiphum maidis fitch. the results showed that no obvious negative effects of two bt corn hybrids dk647bty (event mon810) and nx4777 (event bt11) were observed on the net reproductive rate, average generation time, innate capacity for increase, and finite rate of increase of r. maidis, and ther ...200717650861
patch edges and insect populations.responses of insect populations may be related to patch size and patch edge responses, but it is not clear how to identify these rapidly. we used a random-walk model to identify three qualitative responses to edges: no edge effect (the null model), reflecting edges and absorbing edges. interestingly, no edge effect meant that abundance was lower at edges than in the center of patches, and reflecting edges have similar abundance at edges and centers. we then characterized several insect species' ...200818157553
[quality of different aphids as hosts of the parasitoid lysiphlebus testaceipes (cresson) (hymenoptera: braconidae, aphidiinae)].lysiphlebus testaceipes (cresson) has a broad aphid host range; however the quality of these preys may interfere in its biological feature. this study aimed to evaluate the quality of three macrosiphini, brevicoryne brassicae (l.), lipaphis erysimi (kaltenbach) and myzus persicae (sulzer), and three aphidini schizaphis graminum (rondani) rhopalosiphum maidis (fitch) and aphis gossypii glover as hosts to l. testaceipes and to determine the relation possible of host preference, of size and quality ...200818506297
plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread.abstract thirteen aphid species were tested for their ability to transmit pennsylvania isolates of plum pox virus (ppv) collected in columbia (penn-3), franklin (penn-4), and york (penn-7) counties, pa. four species, aphis fabae, a. spiraecola, brachycaudus persicae, and myzus persicae, consistently transmitted ppv in preliminary transmission tests. two species, metopolophium dirhodum and rhopalosiphum padi, were occasional inefficient vectors. toxoptera citricida, from florida, also was an effe ...200418943108
transmission efficiency of cucumber mosaic virus by aphids associated with virus epidemics in snap bean.cucumber mosaic virus (cmv) is a major component of the virus complex that has become more pronounced in snap bean in the midwestern and northeastern united states since 2001. multiple-vector-transfer tests were done to estimate the cmv transmission efficiencies (p) of the main aphid species identified in commercial snap bean fields in new york and pennsylvania. the four most efficient vectors (p > 0.05) were aphis gossypii, a. glycines, acyrthosiphon pisum, and therioaphis trifolii, which were ...200818943413
variation in transmission efficiency among barley yellow dwarf virus-rmv isolates and clones of the normally inefficient aphid vector, rhopalosiphum padi.the rmv strain of barley yellow dwarf virus (bydv-rmv) is an unassigned member of the luteoviridae that causes barley yellow dwarf in various cereal crops. the virus is most efficiently vectored by the aphid rhopalosiphum maidis, but can also be vectored with varying efficiency by r. padi and schizaphis graminum. field collections of alate aphids migrating into the emerging winter wheat crop in the fall of 1994 in central new york identified a high proportion of r. padi transmitting bydv-rmv. th ...200118944037
transmission, characterization, and serology of a luteovirus associated with yellow leaf syndrome of sugarcane.abstract a previously uncharacterized luteovirus was associated with one form of yellow leaf syndrome (yls), a widespread disease of sugarcane (saccharum sp.). the virus was named sugarcane yellow leaf luteovirus (scylv), and was identified in major sugarcane-producing areas of the world. typical disease symptoms were reproduced when scylv was transmitted by melanaphis sacchari or rhopalosiphum maidis from infected to healthy sugarcane, suggesting that this virus may be the causal agent of one f ...200018944599
design, synthesis and insecticidal activities of novel pyrazole amides containing hydrazone substructures.background: pyrazole and hydrazone derivatives possess good insecticidal activities; their substructural units are widely used in pesticide design. in an effort to discover new molecules with good insecticidal activities, a series of pyrazole amide derivatives containing hydrazone substructures were synthesised and bioassayed. results: bioassays demonstrated that some of the title compounds exhibited notable control of plutella xylostella (linnaeus), helicoverpa armigera (hübner), culex pipiens ...201122190278
accumulation of 5-hydroxynorvaline in maize (zea mays) leaves is induced by insect feeding and abiotic stress.plants produce a wide variety of defensive metabolites to protect themselves against herbivores and pathogens. non-protein amino acids, which are present in many plant species, can have a defensive function through their mis-incorporation during protein synthesis and/or inhibition of biosynthetic pathways in primary metabolism. 5-hydroxynorvaline was identified in a targeted search for previously unknown non-protein amino acids in the leaves of maize (zea mays) inbred line b73. accumulation of t ...201425271262
effects of transgenic bt rice on nontarget rhopalosiphum maidis (homoptera: aphididae).the effects of three transgenic bacillus thuringiensis (bt) rice lines, kmd1, kmd2, and g8-7, on biological parameters and population dynamics of nontarget insect, rhopalosiphum maidis (fitch) (homoptera: aphididae), were investigated in the laboratory and field. no significant differences were found between bt and non-bt rice lines for aphid survival. the developmental time of r. maidis that fed on kmd1 and kmd2 did not differ significantly from those of the individuals feeding on the parental ...201627389683
comparison of gene repertoires and patterns of evolutionary rates in eight aphid species that differ by reproductive mode.in theory, the loss of sexual reproduction is expected to result in the accumulation of deleterious mutations. in aphids, two main types of life cycle, cyclic and obligate parthenogenesis, represent respectively "sexual" and "asexual" reproductive modes. we used the complete pea aphid genome and previously published expressed sequence tags (ests) from two other aphid species. in addition, we obtained 100,000 new ests from five more species. the final set comprised four sexual and four asexual ap ...201222215803
genetic mapping shows intraspecific variation and transgressive segregation for caterpillar-induced aphid resistance in maize.plants in nature have inducible defences that sometimes lead to targeted resistance against particular herbivores, but susceptibility to others. the metabolic diversity and genetic resources available for maize (zea mays) make this a suitable system for a mechanistic study of within-species variation in such plant-mediated interactions between herbivores. beet armyworms (spodoptera exigua) and corn leaf aphids (rhopalosiphum maidis) are two naturally occurring maize herbivores with different fee ...201526462033
near-isogenic lines for measuring phenotypic effects of dimboa-glc methyltransferase activity in maize.three o-methyltransferases (bx10a, b, c) catalyze the conversion of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (dim boa-glc) to 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (hdmboa -glc) in maize (zea mays). variation in benzoxazinoid accumulation and resistance to rhopalosiphum maidis (corn leaf aphid) was attributed to a natural cacta family transposon insertion that inactivates bx10c. whereas maize inbred line b73 has this transposon insertion, line cm l277 does not. to ...201324494232
intraplant communication in maize contributes to defense against insects.the vasculature of plants act as a channel for transport of signal(s) that facilitate long-distance intraplant communication. in maize, maize insect resistance1-cysteine protease (mir1-cp), which has homology to papain-like proteases, provides defense to different feeding guilds of insect pests. furthermore, accumulation of mir1-cp in the vasculature suggests that mir1-cp can potentially function as a phloem-mobile protein. in a recent study, we provided evidence that mir1-cp can curtail the gro ...201627467304
two-spotted ladybeetle adalia bipunctata l. (coleoptera: coccinellidae): a commercially available predator to control asian citrus psyllid diaphorina citri (hemiptera: liviidae).the asian citrus psyllid diaphorina citri kuwayama (hemiptera: liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (hlb) also known as citrus greening disease. the increased use of insecticides for control of d. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. the two-spotted ladybeetle, adalia bipunctata (coleoptera: coccinellidae) is found i ...201627631730
biological aspects of eriopis connexa (germar) (coleoptera: coccinellidae) fed on different insect pests of maize (zea mays l.) and sorghum [sorghum bicolor l. (moench.)].eriopis connexa (germar) (coleoptera: coccinellidae) occurs in several countries of south america and its mass rearing is important for biological control programmes. this work evaluated biological aspects of e. connexa larva fed on eggs of anagasta kuehniella (zeller) (lepidoptera: pyralidae) and spodoptera frugiperda (j. e. smith) (lepidoptera: noctuidae) frozen for one day, fresh eggs of diatraea saccharalis (fabricius) (lepidoptera: pyralidae), s. frugiperda newly-hatched caterpillars, nymph ...201323917572
antifeedant activity of fatty acid esters and phytosterols from echium wildpretii.crude extracts and fractions from echium wildpretii h. pearson ex hook. f. subsp. wildpretii (boraginaceae) have been tested against insect species spodoptera littoralis, leptinotarsa decemlineata, and the aphids myzus persicae, diuraphis noxia, metopolophium dirhodum, rhopalosiphum maidis, and rhopalosiphum padi. the etoh extract and the lipid and steroidal fractions of e. wildpretii exhibited significant antifeedant activities against the aphids and l. decemlineata. two bioactive mixtures comp ...201222422524
the complete nucleotide sequence of the genome of barley yellow dwarf virus-rmv reveals it to be a new polerovirus distantly related to other yellow dwarf viruses.the yellow dwarf viruses (ydvs) of the luteoviridae family represent the most widespread group of cereal viruses worldwide. they include the barley yellow dwarf viruses (bydvs) of genus luteovirus, the cereal yellow dwarf viruses (cydvs) and wheat yellow dwarf virus (wydv) of genus polerovirus. all of these viruses are obligately aphid transmitted and phloem-limited. the first described ydvs (initially all called bydv) were classified by their most efficient vector. one of these viruses, bydv-rm ...201323888156
dynamic maize responses to aphid feeding are revealed by a time series of transcriptomic and metabolomic assays.as a response to insect attack, maize (zea mays) has inducible defenses that involve large changes in gene expression and metabolism. piercing/sucking insects such as corn leaf aphid (rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. to elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line b73 were infested with corn leaf aphids fo ...201526378100
ethylene contributes to maize insect resistance1-mediated maize defense against the phloem sap-sucking corn leaf aphid.signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. previously, it was reported that the synergistic combination of ethylene (et) and jasmonic acid (ja) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (cys) proteinase that is a key defensive protein against chewing insect pests in maize (zea mays). however, this study suggests that mir1-mediated resistance to corn leaf aphid (cla; rhopalosiphu ...201526253737
additive effects of two quantitative trait loci that confer rhopalosiphum maidis (corn leaf aphid) resistance in maize inbred line mo17.plants show considerable within-species variation in their resistance to insect herbivores. in the case of zea mays (cultivated maize), rhopalosiphum maidis (corn leaf aphids) produce approximately twenty times more progeny on inbred line b73 than on inbred line mo17. genetic mapping of this difference in maize aphid resistance identified quantitative trait loci (qtl) on chromosomes 4 and 6, with the mo17 allele reducing aphid reproduction in each case. the chromosome 4 qtl mapping interval incl ...201525249072
natural variation in maize aphid resistance is associated with 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside methyltransferase activity.plants differ greatly in their susceptibility to insect herbivory, suggesting both local adaptation and resistance tradeoffs. we used maize (zea mays) recombinant inbred lines to map a quantitative trait locus (qtl) for the maize leaf aphid (rhopalosiphum maidis) susceptibility to maize chromosome 1. phytochemical analysis revealed that the same locus was also associated with high levels of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (hdmboa-glc) and low levels of 2,4-dihydroxy-7-meth ...201323898034
lady beetle (coleoptera: coccinellidae) communities in soybean and maize.coccinellids provide the most effective natural control of soybean aphid, but outbreaks remain common. previous work suggests that native coccinellids are rare in soybean, potentially limiting soybean aphid control. we compared the coccinellid community in soybean with that of maize to identify differences in how coccinellid species use these habitats. as maize has long been used by coccinellids in the americas, we hypothesized that coccinellids native to the americas would use maize habitats, w ...201626396229
role of olfaction in host finding by aphid parasitoidaphidius nigripes (hymenoptera: aphidiidae).the olfactory responses of the parasitoidaphidius nigripes ashmead were investigated with a four-field airflow olfactometer. female and male parasitoids did not respond to potato plants, the food plant of their host. however, females were strongly attracted by odors from a preferred host,macrosiphum euphorbiae (thomas), and also from less preferred hosts such asmyzus persicae (sulzer) andaphis nasturtii kalt. moreover,a. nigripes females responded positively to odors from a nonhost aphid,rhopalo ...198524310224
do refuge plants favour natural pest control in maize crops?the use of non-crop plants to provide the resources that herbivorous crop pests' natural enemies need is being increasingly incorporated into integrated pest management programs. we evaluated insect functional groups found on three refuges consisting of five different plant species each, planted next to a maize crop in lima, peru, to investigate which refuge favoured natural control of herbivores considered as pests of maize in peru, and which refuge plant traits were more attractive to those de ...201728718835
how the use of nitrogen fertiliser may switch plant suitability for aphids: the case of miscanthus, a promising biomass crop, and the aphid pest rhopalosiphum maidis.the use of nitrogen fertiliser in agrosystems can alter plant nitrogen and consequently improve nutrient availability for herbivores, potentially leading to better performance for herbivores and higher pest pressure in the field. we compared, in laboratory conditions, the effects of nitrogen fertilisation on a promising biomass crop, miscanthus × giganteus, and its parents m. sinensis and m. sacchariflorus. the plant-mediated effects were compared on the second trophic level, the green corn leaf ...201727990748
changes in life history parameters of rhopalosiphum maidis (homoptera: aphididae) under four different elevated temperature and co2 combinations.biological characteristics of corn leaf aphid, rhopalosiphum maidis (fitch), on barley, hordeum vulgare l., were examined for two generations under four different elevated temperature and co2 combinations. the developmental duration for each life stage was significantly reduced under the elevated temperature (+4 degrees c). the elevated co2 (700-750 microl/liter) reduced only the development time of fourth-instar nymph. the overall duration of nymphal stage was reduced in the second generation. ...201425195429
direct and indirect effects of warming on aphids, their predators, and ant mutualists.species exist within communities of other interacting species, so an exogenous force that directly affects one species can indirectly affect all other members of the community. in the case of climate change, many species may be affected directly and subsequently initiate numerous indirect effects that propagate throughout the community. therefore, the net effect of climate change on any one species is a function of the direct and indirect effects. we investigated the direct and indirect effects ...201425039213
effects of relay-intercropping sorghum with winter wheat, alfalfa, and cotton on lady beetle (coleoptera: coccinellidae) abundance and species composition.creating conditions that enhance the abundance of resident populations of natural enemies in agroecosystems is considered critical to the efficiency of biological control of insect pests. we conducted a study to determine the potential of relay-intercropping for enhancing the abundance of aphidophagous lady beetles in sorghum. a relay-intercropping system consisting of alfalfa, winter wheat, and cotton as intercrops and sorghum as a main crop was compared with sorghum monoculture plots at two st ...201020550789
high susceptibility of bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. so-called bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. here we show a remarkable positive effect of bt maize on the performance of the corn leaf aphid rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid hone ...200717622345
identifying key cereal aphid predators by molecular gut analysis.we describe polymerase chain reaction (pcr) primers for gut analysis of aphid predators. the primers amplify aphid mitochondrial coii fragments ranging in size from 77 to 386 bp. using these primers, we were able to distinguish six species of us great plains cereal aphids, including two congeners, rhopalosiphum maidis (fitch) and r. padi (l.), and to detect them in extracts of coccinellid and chrysopid predators. we devised a protocol for deriving half-lives of detectability for the dna of a sin ...200011091324
herbicide (2,4-d) increases insect and pathogen pests on corn.corn leaf aphids, european corn borers, and southern corn leaf blight were more abundant on corn exposed to 2,4-dichlorophenoxyacetic acid (2,4-d) herbicide than they were on unexposed corn. protein levels were higher in corn plants that were exposed to several dosages of 2,4-d, and this may have favored the growth of pests.197617796156
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