Efficacy of pymetrozine against Myzus persicae and in reducing potato virus Y transmission on tobacco plants

Forty‐four parthenogenetic lineages of Myzus persicae s.l. (Sulzer) from tobacco crops and peach orchards located in various regions of Greece were examined to determine their response to the insecticide pymetrozine using leaf‐dip bio‐assays. The results show that the aphid has not developed resistance, as all lineages exhibited resistance factors bellow 6.0. In transmission experiments of potato virus Y (PVY) using a lineage of the tobacco‐adapted subspecies M. persicae nicotianae Blackman on tobacco plants, one foliar application with pymetrozine provided adequate protection for 7 days. Pymetrozine significantly reduced both virus acquisition and inoculation compared with the untreated control and the reduction was comparable to a mineral oil application. These results are discussed in terms of the advantage of incorporating pymetrozine as a compound of pest management strategies against M. persicae s.l. and for control of non‐persistent viruses, especially in crops such as tobacco because of the high selection pressure from neonicotinoids resulting in potential of resistance developing in aphid populations.     

Behavioural differences during host selection between alate virginoparae of generalist and tobacco-specialist Myzus persicae

Host plant selection and acceptance by aphids involves four consecutive steps: (1) prealighting behaviour, (2) leaf surface exploration and probing of subepidermal tissues, (3) deep probing of plant tissues, and (4) evaluation of the phloem sap. Host specialisation in aphids may involve not only different performances on potential hosts, but also different strategies for host selection and acceptance. Myzus persicae s.s. (Sulzer) (Homoptera: Aphididae) is one of the most polyphagous aphid species, although a tobacco‐adapted subspecies, M. persicae nicotianae, has been described. These two taxa constitute a good system for studying the effect of host range on host selection strategies. We studied the first two steps in the host selection process by alate virginoparae of M. persicae s.s. and M. persicae nicotianae on host and non‐host plants, using three types of behavioural assays: wind tunnel, olfactometry, and video‐recording. Alate virginoparae of M. persicae nicotianae recognised and chose their host plant more efficiently than M. persicae s.s., on the basis of olfactory and visual cues, and factors residing at cuticular and subcuticular levels. Host recognition was evident before phloem tissues were contacted. Olfactory cues were apparently not involved in host selection by M. persicae s.s.     

3种寄主上桃蚜的选择性及形态分化

桃蚜是一种重要的农业害虫,寄主广泛,种下分化复杂。以采自黄土高原旱作区桃树、烟草、甘蓝上的桃蚜为研究对象,通过叶片选择法、传统比较形态测定法研究了3种寄主上桃蚜的选择性及形态分化。结果表明:在3种寄主同时存在的情况下,烟草上的桃蚜嗜食烟草,表现为63.5%的桃蚜选择烟草叶,13.8%选择甘蓝叶,8.2%选择桃叶,而甘蓝和桃树上的桃蚜对原寄主没有表现出明显的嗜好性;从形态指标来看,3种寄主上的桃蚜在体长、触角末节长度、后足腿节长度、触角与体长的比例方面存在显著差异(P0.05),说明这几个特征可以作为区分这3种寄主上桃蚜的依据。综合分析可以初步认为黄土高原旱作区烟草上的桃蚜可能形成了寄主专化型-烟草型。     

Abscisic acid deficiency increases defence responses against Myzus persicae in Arabidopsis

Comparison of Arabidopsis thaliana (Arabidopsis) gene expression induced by Myzus persicae (green peach aphid) feeding, aphid saliva infiltration and abscisic acid (ABA) treatment showed a significant positive correlation. In particular, ABA‐regulated genes are over‐represented among genes that are induced by M. persicae saliva infiltration into Arabidopsis leaves. This suggests that the induction of ABA‐related gene expression could be an important component of the Arabidopsis–aphid interaction. Consistent with this hypothesis, M. persicae populations induced ABA production in wild‐type plants. Furthermore, aphid populations were smaller on Arabidopsis aba1‐1 mutants, which cannot synthesize ABA, and showed a significant preference for wild‐type plants compared with the mutant. Total free amino acids, which play an important role in aphid nutrition, were not altered in the aba1‐1 mutant line, but the levels of isoleucine (Ile) and tryptophan (Trp) were differentially affected by aphids in wild‐type and mutant plants. Recently, indole glucosinolates have been shown to promote aphid resistance in Arabidopsis. In this study, 4‐methoxyindol‐3‐ylmethylglucosinolate was more abundant in the aba1‐1 mutant than in wild‐type Arabidopsis, suggesting that the induction of ABA signals that decrease the accumulation of defence compounds may be beneficial for aphids.     

Survival, growth, and reproduction of two aphid species on sucrose solutions containing host or non-host honeydews

Aphids, like most phloem-feeding insects, commonly exhibit a high degree of host specificity. Plant-specific chemical compounds are likely to serve as important host selection cues for monophagous aphids and such substances could be present in aphid honeydew. Apterous virginoparae ofMyzus persicae (Sulzer) andPhorodon humuli (Schrank) were reared on a buffered sucrose solution containing various aphid honeydews or a mixture of amino acids. In two separate experiments, the host-specificP. humuli (hop aphid) could grow and reproduce only on diets containing honeydew collected from hop (Humulus lupulus L.).M. persicae (the green peach aphid, GPA) did not perform well on diets containing hop honeydew, perhaps because hop is a poor GPA host. Honeydew collected from preferred GPA host plants rape,Brassica napus L., and jimsonweed,Datura stramonium L., allowed GPA growth and reproduction. Hop aphids, however, performed poorly on rape and jimsonweed honeydew diets. Bell pepper,Capsicum annuum L., honeydew supported neither the hop aphid nor GPA. The study of aphid honeydew components may contribute towards a more complete understanding of host preference and selection phenomena in aphids.     

Genetic variability in host plant adaptation of the green peach aphid, Myzus persicae

The green peach aphid, Myzus persicae (Sulz.), is polyphagous on over 400 plant species in more than 50 families. Phenotypic plasticity of individuals and genetic variability in the population presumably contribute to this polyphagy. The genetic variability in field populations of M. persicae was assessed with respect to their adaptation to sugar beets and potatoes. An analysis of more than 1 000 clones, sampled during 1980, 1981 and 1982 from different host plants in the field, revealed a wide genetic variability in host plant adaptation to sugar beets as well as to potatoes. Both traits seem to be inherited independently from each other and do not correlate with clone-specific host plant preference of apterous adults. The aphid M. persicae can be characterized as a polyphagous insect species with a wide, continuously distributed variability and a broad phenotypic plasticity. A general differentiation of herbivorous species into generalists and specialists tends to ignore the genetic component in the complex of insect-plant relationships.

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Zusammenfassung Die Grüne Pfirsichblattlaus Myzus persicae (Sulz.) lebt polyphag an über 400 Pflanzenarten in mehr als 50 Pflanzenfamilien. Ein breites Nahrungsspektrum einer Art ergibt sich jedoch aus der phänotypischen Plastizität des Individuums oder einer Klonlinie und der genetischen Variabilität der Population. Felpopulationen der Grünen Pfirsichblattlaus wurden auf ihre genetische Variabilität bezüglich der Wirtspflanzenanpassung an Rübe und Kartoffel untersucht. Eine Analyse von mehr als 1 000 Klonen, die über die Jahre 1980, 1981 und 1982 im Rheinland gesammelt wurden, lassen eine breite Variabilität in der Wirtspflanzenanpassung der Population erkennen. Beide Merkmale scheinen unabhängig voneinander vererbt zu werden und zeigen keine Beziehung zum Wirtswahlverhalten adult apterer Läuse der entsprechenden Klone. Die Art M. persicae kann daher charakterisiert werden als eine polyphage Insektenart mit einer breiten genetischen Variabilität und einer grossen phänotypischen Plastizität. Eine generelle Differenzierung von Herbivoren in Generalisten und Spezialisten vernachlässigt die genetische Komponente in der komplexen Beziehung zwischen Insekten un ihren Wirtspflanzen.

     

Egg production by the coccinellid Hippodamia convergens fed on two morphs of the green peach aphid, Myzus persicae

Adults of the lady beetle Hippodamia convergens Guérin-Méneville requiring aphids for egg production, were fed suboptimal amounts of apteriform virginoparous larvae or alatiform gynoparous larvae of the green peach aphid, Myzus persicae (Sulz.), and artificial diet ad lib. The beetles initiated oviposition sooner and deposited significantly more eggs when supplied with the same weight of apterous virginoparous morph. The possible nutritional, hormonal, and ecological implications of the findings are discussed.

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Zusammenfassung Die Eiproduktion des Marienkäfers Hippodamia convergens, welcher hierzu Blattläuse als Nahrung benötigt, wurde bei Fütterung mit zwei verschiedenen Morphen der Blattlaus Myzus persicae untersucht. Der Verzehr derselben Menge flügelloser Virginoparen führte im Vergleich zu geflügelten Gynoparen zu früherer und signifikant erhöhter Eiabgabe. Der hormonale und ernährungsphysiologische Hintergrund und die ökologische Bedeutung dieser Ergebnisse werden diskutiert.

     

Ecological genetics of Italian peach‐potato aphid (Myzus persicae) populations in relation to geography,dispersal and insecticide resistance as studied using microsatellite and resistance markers

相似文献   

Response of Solanum tuberosum to Myzus persicae infestation at different stages of foliage maturity

Young leaves of the potato Solanum tuberosum L. cultivar Kardal contain resistance factors to the green peach aphid Myzuspersicae （Sulzer） （Hemiptera： Aphididae） and normal probing behavior is impeded. However, M. persicae can survive and reproduce on mature and senescent leaves of the cv. Kardal plant without problems. We compared the settling ofM. persicae on young and old leaves and analyzed the impact of aphids settling on the plant in terms of gene expression. Settling, as measured by aphid numbers staying on young or old leaves, showed that after 21 h significantly fewer aphids were found on the young leaves. At earlier time points there were no difference between young and old leaves, suggesting that the young leaf resistance factors are not located at the surface level but deeper in the tissue. Gene expression was measured in plants at 96 h postinfestation, which is at a late stage in the interaction and in compatible interactions this is long enough for host plant acceptance to occur. In old leaves of cv. Kardal （compatible interaction）, M. persicae infestation elicited a higher number of differentially regulated genes than in young leaves. The plant response to aphid infestation included a larger number of genes induced than repressed, and the proportion of induced versus repressed genes was larger in young than in old leaves. Several genes changing expression seem to be involved in changing the metabolic state of the leaf from source to sink.     

Genetic variation in Myzus persicae populations associated with host-plant and life cycle category

Random amplified polymorphic DNA (RAPD) analysis was applied on 96 clones of Myzus persicae (Sulzer) (Homoptera: Aphididae) representing seven populations collected from different host-plants and regions of Greece. Ten decamer random primers were used to evaluate genetic variation among the examined samples. Despite the variability found between clones, no specific RAPD marker was detected to discriminate the different populations. A significant finding was that aphids from peach and pepper, which were collected far away from tobacco-growing regions, especially those from peach, showed genetic divergence from the tobacco-feeding clones. Moreover, data analysis revealed a significant genetic divergence between holocyclic and anholocyclic populations from tobacco. Lastly, holocyclic clones showed higher level of estimated heterozygosity than the nonholocyclic (anholocyclic, androcyclic and intermediate) ones.     

Effects of aluminum mulch on fecundity of apterous Myzus persicae on head lettuce in a field planting

Head lettuce field plantings were artificially infested with apterous adults of the green peach aphid, Myzus persicae (Sulzer). Significantly greater aphid fecundity was demonstrated on plants grown through aluminum-coated construction paper than on plants grown on bare soil. Higher temperatures and host-plant physiology were factors modified by the mulch, and could have resulted in larger aphid populations on plants grown over a reflective surface as the season progressed. Faster plant growth and a significantly larger yield per head of lettuce also resulted from the use of the aluminum mulch. The incidence of a leafhopper-borne plant disease, aster yellows, was significantly reduced on head lettuce in the aluminum mulch plots.

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Résumé Des cultures de laitue ont été artificiellement contaminées avec des adultes aptères de Myzus persicae. La fécondité a été significativement augmentée sur les plantes poussant sur un sol recouvert par un voile d'aluminium, comparées à celles poussant sur un sol nu. Cette augmentation pourrait entrainer des populations de pucerons de plus en plus importantes, au fur et à mesure de l'avancement de la saison, sur les plantes poussant au dessus d'une surface fortement réfléchissante. L'utilisation du voile d'aluminium a provoqué simultanément une accélération de la croissance et une augmentation des rendements de laitue. Ces résultats semblent dus à une augmentation de la température diurne, à une meilleure conservation de l'humidité et à une plus forte réflexion de la lumière lorsqu'il y a présence de voile d'aluminium. Par aulleurs, les dégâts provoqués sur feuilles par les germes pathogénes transmis par les Cicadelles delles sont significativement plus rares sur sol couvert de voile d'aluminium.

     

Expression of snowdrop lectin in transgenic tobacco plants results in added protection against aphids

The range of sap-sucking insect pests to which GNA, (the mannose specific lectin from snowdrops (Galanthus nivalis) has been shown to be insecticidal in artificial diets has been extended to include the peach potato aphid (Myzus persicae). A gene construct for constitutive expression of GNA from the CaMV35S gene promoter has been introduced into tobacco plants. A transgenic tobacco line which expresses high levels of GNA has been shown to have enhanced resistance toM. persicae in leaf disc and whole plant bioassays,demonstrating the potential for extending transgenic plant technology to the control of sap-sucking insect pests.     

Probing behavior of aposymbiotic green peach aphid (Myzus persicae) on susceptible Solanum tuberosum and resistant Solanum stoloniferum plants

The green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae) is one of the potato important pests; it is the most efficient vector of potato viruses. Myzus persicae harbors the endosymbiotic bacteria Buchnera aphidicola which supplements their diet. There is increasing evidence that B. aphidicola is involved in plant–aphid interactions and we previously demonstrated that B. aphidicola disruption (aposymbiosis) affected the probing behavior of M. persicae on radish plants, delaying host plant acceptance. In this work, we evaluated the effect of aposymbiosis on the probing behavior of M. persicae on 2 Solanum species with different compatibility with M. persicae, Solanum tuberosum (susceptible) and Solanum stoloniferum (resistant) with the electrical penetration graph technique (EPG). To disrupt B. aphidicola, rifampicin was administered to aphids through artificial diets. Aposymbiotic aphids, on both plant species, showed increased pathway activities, mechanical problems with the stylets, and delayed salivation in the phloem. The extended time in derailed stylet mechanics affected the occurrence of most other probing activities; it delayed the time to the first phloem phase and prevented ingestion from the phloem. The effect of aposymbiosis was more evident in the compatible interaction of M. persicae–S. tuberosum, than in the incompatible interaction with S. stoloniferum, which generated the M. persicae–S. tuberosum interaction to become incompatible. These results confirm that B. aphidicola is involved in the plant–aphid interaction in relation to plant acceptance, presumably through a role in stylets penetration in the plant.     

Ecological genetics of host plant exploitation in the green peach aphid, Myzus persicae

The ecological consequences of genetic variability in host plant exploitation of Myzus persicae (Hemiptera, Aphididae) were studied in several agro-ecosystems, differing in crop plant heterogeneity. An analysis of aphid populations sampled from sugar beet, potatoes, and lettuce revealed changes in the frequency distribution of aphid clones according to their respective host plant adaptations. The spatial unit of differentiation was below an average field size of 3–5 hectares and a differentiation could be found in the centre of potato and sugar beet fields but not at the edge of the fields. On a temporal scale, the differentiation of populations is transitory even on a large-scale basis of highly specialized cropping areas. The ecological parameters of differentiation are discussed with special reference to agro-ecosystems and integrated pest management. Increasing the genetic heterogeneity of crop fields may help to reduce population outbreaks.

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Zusammenfassung Die ökologischen Konsequenzen genetischer Variabilität in der Wirtspflanzennutzung von Myzus persicae (Hemiptera, Aphididae) wurden in mehreren Agro-Ökosystemen untersucht, die sich in der Kulturpflanzenheterogenität unterscheiden. Eine Analyse von auf Rüben, Kartoffeln und Salat siedelnden Populationen zeigte eine genetische Differenzierung in Wirtspflanzen-angepaßte Feld-populationen. Die räumliche Einheit solcher Differenzierungen liegt unterhalb einer Feldgröße von 3–5 ha. Eine Differenzierung konnte hier in der Mitte der Felder aber nicht am Rand festgestellt werden. Aus zeitlicher Sicht ist die Differenzierung selbst in großräumigen, spezialisierten Anbaugebieten nur vorübergehend feststellbar. Die ökologischen Parameter der Differenzierung werden besonders in Hinsicht auf die integrierte Schädlingsbekämpfung in Agro-ökosystemen diskutiert. Eine Erhöhung der genetischen Heterogenität von Kulturpflanzenbeständen kann möglicherweise zu einer Verringerung von Blattlaus-Massenvermehrungen beitragen.

     

Transformation of Tobacco with Genes Encoding Helianthus Tuberosus Agglutinin (HTA) Confers Resistance to Peach-Potato Aphid (Myzus persicae)

The effects of the hta gene encoding Helianthus tuberosus agglutinin (HTA) on an insect in the order Homoptera were investigated. Homologous cDNAs of hta-a, hta-b, hta-c and hta-d with CaMV35S as promoter were introduced into tobacco via Agrobacterium tumefaciens. Southern blot results showed that the exogenous hta gene was inserted into the genome of host plants, and northern blot analysis confirmed that hta was expressed in transgenic plants. A bioassay with peach-potato aphid (Myzus persicae) demonstrated that transgenic plants had deleterious effects on the insect. The average population of aphids fed on transgenic T₀ plants during an 11-day assay decreased by 70%, compared controls. In transgenic plants of T₁ generation, aphid fecundity inhibitions were 53.0%(hta-b) and 64.6% (hta-c), respectively. The development of aphids was notably retarded. We conclude that hta could be a novel and promising candidate for plant transgenic engineering against homopteran insect pests.     

Density-dependent regulation in populations of potato-colonizing aphids

Scarcity of long-term (over 30 years) data series represents a major challenge for an accurate estimation of the role of density-dependent processes in population regulation. We analyzed population densities of the wingless parthenogenic morphs of buckthorn aphid (BA), Aphis nasturtii Kaltenbach, potato aphid (PA), Macrosiphum euphorbiae (Thomas), and green peach aphid (GPA), Myzus persicae (Sulzer) from 1949 to 2003 for signs of density-dependent regulation. We found strong evidence of density-dependent regulation, with detection of density dependence being fairly consistent among the different statistical techniques. Direct density dependence was detected for the populations of all three species. There was also evidence of delayed density dependence for PA. The periodicity of population fluctuations for BA and GPA was 6.1 years and 3.9 years, respectively. The periodicity for PA was not explicit, being highly variable throughout the time series. Effects of density-independent weather factors were relatively minor compared to density-dependent regulation. The BA populations experienced a significant reduction in both density and annual oscillations starting in 1995, while GPA populations experienced a similar reduction in 1991. No such change was apparent for PA. The most likely explanation for the observed phenomenon is a change in the composition of the lady beetle community following the establishment of two alien coccinellid species, and/or changes in insecticide use by commercial growers in the area of the study.     

Insect growth regulating effects of neem extract and azadirachtin on aphids

Neem,Azadirachta indica (A. Juss.), seed oil (NSO) applied to leaf discs at a concentration of 1.0% resulted in 94% to 100% mortality of second instar nymphs of currant-lettuce aphid,Nasonovia ribis-nigri (Mosley), and green peach aphid,Myzus persicae (Sulzer), after nine days. The equivalent amount of pure azadirachtin (AZA) (≈40 ppm), the principle active ingredient of neem, was as effective as NSO. The survival of adult aphids was unaffected by NSO or AZA, but the survival of offspring from treated adultM. persicae andN. ribis-nigri was reduced significantly. The lethal concentration of AZA resulting in 50% mortality of second instar nymphs of nine species of aphids ranged from 2.4 ppm forM. persicae on pepper to 635.0 ppm for the strawberry aphid,Chaetosiphon fragaefolii (Cockerell), on strawberry. ForM. persicae, the growth regulating effect of AZA was influenced by the host plant and the nymphal instar treated.     

Aphid populations showing differential levels of virulence on Capsicum accessions

The green peach aphid,Myzus persicae,is one of the most threatening pests in pepper cultivation and growers would benefit from resistant varietices.Previously,we identified two Capsicum acessions as susceptible and three as resistant to M.persicae using an aphid population originating from the Netherlands(NL).Later on we identified an aphid population originating from a diferent gcographical region(Switserland,SW)that was virulent on all tested Capsicum acessions.The objeetive of the current work is to describe in detail diferent aspects of the interaction between two aphid populations and two sclected Capsicum acessions(one that was susceptible[PB2013046]and one that was resistant[PB2013071]to population NL),including biochemical processes involved.Electrical penetration graph(EPG)recordings showed similar feeding activities for both aphid populations on PB2013046.On acession PB2013071 the aphid population sw was able to devote significantly more time to phloem ingestion than population NL.We also studied plant defense response and found that plants of acession PB2013046 could not induce an accumulation of reactive oxygen species and callose formation after infestation with either aphid population.However,plants of PB2013071 induced a stronger defense response after infestation by population NL than after infestation by population SW.Based on these results,population SW of M.persicae seems to have overcome the resistance of PB2013071 that prevented feeding of aphids from NL population.The potential mechanism by which SW population overcomes the resistance is discussed.     

Annotated expressed sequence tags and xenobiotic detoxification in the aphid Myzus persicae （Sulzer）

Aphids （Hemiptera： Aphididae） are phytophagous insects that are important agricultural pests. The enormous negative economic impacts caused by aphids worldwide are well known, and are mostly due to their high multiplication rate and the transmission of phytopathogenic viruses. Aphid management strategies mainly involve chemical treatments which are pollutants and are increasingly inefficient, since aphids have developed multiple insecticide-resistant mechanisms. Among the most economically important species is the green peach aptfid Myzus persicae Sulzer （Aphididae： Macrosiphini）, which is able to colonize a wide range of host plants belonging to many different families, and transmits numerous plant viruses. Because of its large prevalence, M. persicae has been the target of massive insecticide treatments; consequently, it has evolved several insecticide-resistant mechanisms. In this work, a collection of expressed genes from M. persicae is presented in order to identify putative genes involved in xenobiotic detoxification. After cDNA cloning and sequencing, 959 expressed sequence tags （EST） were annotated. Most sequences matched known genes corresponded to metabolism proteins （26%）, ribosomal proteins （ 23 % ） and structural proteins （8%）. Among them, several sequences corresponded to proteins putatively involved in sensing, degradation or detoxification of plant xenobiotic products.     

Proteomic analysis of Arabidopsis thaliana (L.) Heynh responses to a generalist sucking pest (Myzus persicae Sulzer)

Herbivorous insects can cause severe cellular changes to plant foliage following infestations, depending on feeding behaviour. Here, a proteomic study was conducted to investigate the influence of green peach aphid (Myzus persicae Sulzer) as a polyphagous pest on the defence response of Arabidopsis thaliana (L.) Heynh after aphid colony establishment on the host plant (3 days). Analysis of about 574 protein spots on 2‐DE gels revealed 31 differentially expressed protein spots. Twenty out of these 31 differential proteins were selected for analysis by mass spectrometry. In 12 of the 20 analysed spots, we identified seven and nine proteins using MALDI‐TOF‐MS and LC‐ESI‐MS/MS, respectively. Of the analysed spots, 25% contain two proteins. Different metabolic pathways were modulated in Arabidopsis leaves according to aphid feeding: most corresponded to carbohydrate, amino acid and energy metabolism, photosynthesis, defence response and translation. This paper has established a survey of early alterations induced in the proteome of Arabidopsis by M. persicae aphids. It provides valuable insights into the complex responses of plants to biological stress, particularly for herbivorous insects with sucking feeding behaviour.