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Characterization of electrical penetration graphs of the Asian citrus psyllid, Diaphorina citri, in sweet orange seedlings

BONANI, J. P.; FERERES, A.; GARZO, E.; MIRANDA, M. P.; APPEZZATO-DA-GLORIA, B.; LOPES, J. R. S.
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.18%
Detailed information on probing behavior of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is critical for understanding the transmission process of phloem-limited bacteria (Candidatus Liberibacter spp.) associated with citrus `huanglongbing` by this vector. In this study, we investigated stylet penetration activities of D. citri on seedlings of Citrus sinensis (L.) Osbeck cv. Pera (Rutaceae) by using the electrical penetration graph (EPG-DC system) technique. EPG waveforms were described based on amplitude, frequency, voltage level, and electrical origin of the observed traces during stylet penetration into plant tissues. The main waveforms were correlated with histological observations of salivary sheath termini in plant tissues, to determine the putative location of stylet tips. The behavioral activities were also inferred based on waveform similarities in relation to other Sternorrhyncha, particularly aphids and whiteflies. In addition, we correlated the occurrence of specific waveforms with the acquisition of the phloem-limited bacterium Ca. Liberibacter asiaticus by D. citri. The occurrence of a G-like xylem sap ingestion waveform in starved and unstarved psyllids was also compared. By analyzing 8-h EPGs of adult females...

Characterization of electrical penetration graphs of Bucephalogonia xanthophis, a vector of Xylella fastidiosa in citrus

MIRANDA, M. P.; FERERES, A.; APPEZZATO-DA-GLORIA, B.; LOPES, J. R. S.
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.26%
The sharpshooter Bucephalogonia xanthophis (Berg) (Homoptera: Cicadellidae) is a vector of the xylem-limited bacterium, Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner), which causes citrus variegated chlorosis. Despite the importance of citrus variegated chlorosis, the probing behavior of vectors on citrus and its implications for transmission of X. fastidiosa have not been studied. Here we studied electrical penetration graph (EPG-DC system) waveforms produced by B. xanthophis on Citrus sinensis (L.) Osbeck (Rutaceae), and their relationships with stylet activities and xylem ingestion. Electrical penetration graph waveforms were described based on amplitude, frequency, voltage level, and electrical origin of the observed traces during stylet penetration on plant tissues. The main waveforms were correlated with histological observations of salivary sheaths in plant tissues and excretion analysis, in order to determine stylet activities and their precise position. Six waveforms and associated activities are described: (S) secretion of salivary sheath and intracellular stylet pathway, (R) resting during stylet pathway, (Xc) contact of stylets with xylem vessels, (Xi) active xylem ingestion, (N) interruption within the xylem phase (during Xc or Xi)...

Caracterização do aparelho bucal e comportamento alimentar de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) em Citrus sinensis (L.) Osbeck; Caracterization of the mouth aparatus and feeding behavior of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) on Citrus sinensis (L.) Osbeck

Bonani, Jean Patrick
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/04/2009 Português
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O psilídeo Diaphorina citri é vetor das bactérias Candidatus Liberibacter asiaticus e Ca. L. americanus, associadas ao Huanglongbing (HLB) dos citros. Apesar da grande importância desta doença no mundo, sabe-se pouco sobre a atividade alimentar deste vetor, o que seria fundamental para entender o processo de transmissão desses patógenos e aprimorar estratégias de manejo da doença. Assim, esta pesquisa teve por objetivos: a) examinar aspectos morfológicos do aparato bucal de D. citri; b) caracterizar o seu comportamento alimentar em mudas de laranja doce (Citrus sinensis) através da técnica de Electrical Penetration Graph (EPG)-sistema DC; e c) avaliar o efeito da idade de folhas cítricas na penetração estiletar deste inseto e na eficiência de aquisição de Ca. L. asiaticus. Adultos de D. citri apresentam um rostro que se projeta logo após o par de coxas protoráxicas. Verificou-se que na extremidade distal desta estrutura há quatro pares de sensilas em simetria bilateral. O rostro abriga um feixe de quatro estiletes (2 mandíbulas e 2 maxilas) com comprimento médio de 512 µm. Os estiletes maxilares se acoplam formando os canais alimentar e salivar com diâmetros de 0,90 µm e 0,47 µm, respectivamente; esses dois canais se fundem próximo à extremidade distal de uma das maxilas para formar um canal comum...

Resistance inducing agents on the biology and probing behaviour of the greenbug in wheat

Pereira, Rosane Rodrigues Costa; Moraes, Jair Campos; Prado, Ernesto; Dacosta, Ronelza Rodrigues
Fonte: Universidade de São Paulo (USP), Escola Superior de Agricultura Luiz de Queiroz (ESALQ) Publicador: Universidade de São Paulo (USP), Escola Superior de Agricultura Luiz de Queiroz (ESALQ)
Tipo: Artigo de Revista Científica Formato: 430-434
Português
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); O pulgão-verde Schizaphis graminum (Rond.) (Hemiptera: Aphididae) é um dos principais insetos- praga da cultura do trigo (Triticum aestivum, L.). Agentes que induzem resistência como silício e acibenzolars-methyl (ASM) podem fornecer proteção às plantas contra insetos e doenças. Avaliou-se o efeito do silício e/ ou ASM no desenvolvimento e comportamento alimentar de S. graminum em plantas de trigo. Plantas de trigo cultivar Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 22 foram tratadas com silício (ácido silícico a 1%) e acibenzolar-S-methyl (ASM) a 0.5%. Os parâmetros estudados foram biologia, excreção de honeydew e comportamento alimentar (de prova) monitorado por meio da técnica Electrical Penetration Graphs (EPG). Para o estudo de biologia e excreção de honeydew foram usadas dez repetições e 25 para EPG. A aplicação de agentes indutores de resistência reduziu o número de ninfas, prolongando a duração de período de pré-reprodutivo e o número de gotas de honeydew. O efeito de resistência foi localizado principalmente no floema, com redução de ingestão de seiva elaborada.; The greenbug Schizaphis graminum (Rond.) (Hemiptera: Aphididae) is one of the main pestinsects of wheat (Triticum aestivum...

Resistance inducing agents on the biology and probing behaviour of the greenbug in wheat

Pereira,Rosane Rodrigues Costa; Moraes,Jair Campos; Prado,Ernesto; Dacosta,Ronelza Rodrigues
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2010 Português
Relevância na Pesquisa
35.99%
The greenbug Schizaphis graminum (Rond.) (Hemiptera: Aphididae) is one of the main pestinsects of wheat (Triticum aestivum, L.). Resistance inducing agents as silicon (Si) and acibenzolar-s-methyl (ASM) can provide some protection against insects and diseases. The effect of Si and/or ASM on the development and probing behaviour of S. graminum in wheat plants was evaluated. Wheat plants (cultivar Embrapa 22) were treated with Si (silicic acid at the rate of 1%) and acibenzolar-S-methyl (ASM) at the rate of 0.5%. The effects of these treatments on greenbugs were analyzed by development parameters, honeydew excretion and probing behavior monitored by Electrical Penetration Graphs (EPG). The development and honeydew experiments consisted of ten replications each and EPG experiment was replicated 25 times. The application of both resistance inducing agents reduced fecundity, prolonged the duration of pre-reproductive period, and decreased honeydew production. Induced resistance was localized mainly at phloem level and caused a strong reduction of phloem sap ingestion, but some effect of ASM at parenchyma/mesophyll level could not be discounted as far fewer aphids reached the sieve elements.

Probing Behavior of Apterous and Alate Morphs of two Potato—Colonizing Aphids

Boquel, Sébastien; Giordanengo, Philippe; Ameline, Arnaud
Fonte: University of Wisconsin Library Publicador: University of Wisconsin Library
Tipo: Artigo de Revista Científica
Publicado em 02/12/2011 Português
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Secondary host plant colonization by aphids involves alate and apterous morphs to spread in the population at a large scale by flying or, at a finer one, by walking. Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae) and Myzus persicae Sulzer (Hemiptera: Aphididae) are two polyphagous aphids that cause serious losses on many crops, particularly on potato, Solanum tuberosum L. (Solanales: Solanaceae). When settlement of virginoparous alate aphids occurs, apterous individuals are produced and spread within the potato field. As these two potato colonizers originate from different areas and show different body length, this study compared probing behaviors of virginoparous alate and apterous M. persicae and M. euphorbiae on one of their secondary host plants, Solanum tuberosum. Non—choice bioassays and electrical penetration graph (EPG) recordings were performed. Most M. euphorbiae of the two morphs rapidly accepted potato plants and exhibited long duration of probing, phloem sap salivation, and ingestion phases. In contrast, at the end of the experiment, most alates of M. persicae left the potato leaflet after brief gustative probes. Moreover, EPG experiments showed that the main difference between both morphs of the two species concerned the xylem ingestion parameter. Differences between species were also reported...

A Plant Virus Manipulates the Behavior of Its Whitefly Vector to Enhance Its Transmission Efficiency and Spread

Moreno-Delafuente, Ana; Garzo, Elisa; Moreno, Aranzazu; Fereres, Alberto
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 16/04/2013 Português
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Plant viruses can produce direct and plant-mediated indirect effects on their insect vectors, modifying their life cycle, fitness and behavior. Viruses may benefit from such changes leading to enhanced transmission efficiency and spread. In our study, female adults of Bemisia tabaci were subjected to an acquisition access period of 72 h in Tomato yellow leaf curl virus (TYLCV)-infected and non-infected tomato plants to obtain viruliferous and non-viruliferous whiteflies, respectively. Insects that were exposed to virus-infected plants were checked by PCR to verify their viruliferous status. Results of the Ethovision video tracking bioassays indicated that TYLCV induced an arrestant behavior of B. tabaci, as viruliferous whitefly adults remained motionless for more time and moved slower than non-viruliferous whiteflies after their first contact with eggplant leaf discs. In fact, Electrical Penetration Graphs showed that TYLCV-viruliferous B. tabaci fed more often from phloem sieve elements and made a larger number of phloem contacts (increased number of E1, E2 and sustained E2 per insect, p<0.05) in eggplants than non-viruliferous whiteflies. Furthermore, the duration of the salivation phase in phloem sieve elements (E1) preceding sustained sap ingestion was longer in viruliferous than in non-viruliferous whiteflies (p<0.05). This particular probing behavior is known to significantly enhance the inoculation efficiency of TYLCV by B. tabaci. Our results show evidence that TYLCV directly manipulates the settling...

Probing Behavior of Aphis gossypii on Resistant and Susceptible Muskmelon

Kennedy, G. G.; McLean, D. L.; Kinsey, M. G.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
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Microscopic examination of stylets and sheaths and electronic recording of the probing behavior of the melon aphid on resistant and susceptible muskmelon revealed pronounced differences in probing on the 2 lines. Relative to the susceptible line, ‘Top Mark,’ stylets and sheaths in the resistant line, 91213, had significantly more branches ending in the phloem. Electronic recording of aphid probing revealed that on the resistant plants a significantly greater percentage of the probes led to stylet contact with the phloem sieve cells, but a smaller proportion of the sieve cell contacts resulted in ingestion than was the case on susceptible plants. In addition, the duration of periods of ingestion from the sieve cells was 2- to 3× greater on susceptible than on resistant plants.

Probing and Feeding Behavior of Two Distinct Biotypes of Bemisia tabaci (Homoptera: Aleyrodidae) on Tomato Plants

Jiang, Y. X.; Lei, H.; Collar, J. L.; Martin, B.; Muñiz, M.; Fereres, A.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
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The probing and feeding behavior of 2 biotypes (B and Q) of the sweetpotato whitefly, Bemisia tabaci (Gennadius), were monitored using the electrical penetration graph (EPG) technique on tomato, Lycopersicon esculentum (Mill) (‘Riofuego’). Seven EPG waveform patterns were distinguished. B. tabaci (B biotype) showed a shorter duration of potential drop pattern (4.73 ± 0.45 s [mean ± SE], n = 125), longer time to reach the phloem (209 ± 23.42 min, n = 22), and more complex pathway patterns than the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Some differences were observed in feeding behavior of the 2 B. tabaci biotypes (B and Q) tested. Interestingly, significant differences (P< 0.05) were found in those parameters related with phloem events: total duration of the E(pd), E(pd)1, and E(pd)2 (P < 0.01), as well as mean duration of E(pd) and E(pd)2. In addition, there also were significant differences in the total number of probes (P< 0.05). The Q biotype showed fewer number of probes and a longer phloem ingestion time (pattern E(pd)2) than those from the B biotype. Hence, our results revealed a clear difference in the probing and feeding behavior between the B and the Q biotypes of B. tabaci on tomato plants.

Synthesis, thermal behavior, and aggregation in aqueous solution of poly(methyl methacrylate)-b-poly(2-hydroxyethyl methacrylate)

ACEVEDO, B.; MARTINEZ, F.; OLEA, A. F.
Fonte: 2014 Sociedad Chilena de Química Publicador: 2014 Sociedad Chilena de Química
Tipo: Artigo de Revista Científica
Português
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Indexación: Scielo; ABSTRACT Amphiphilic block copolymers of poly(methyl methacrylate) PMMA and poly(2-hidroxyethyl methacrylate) PHEMA were synthesized by a two-step atom transfer radical polymerization (ATRP). Copolymers with various degrees of polymerization and different relative block sizes were obtained. The structure of the resulting polymers have been characterized and verified by FT-IR and 1H-NMR, molecular weight were determined by size exclusion chromatography analyses. The thermal properties of these polymers were investigated by differential scanning calorimetry DSC and thermogravimetric analysis TGA. The glass transition temperature of mono halogenated PMMA increases from 116 °C to 123 °C with increasing molecular weight, whereas the glass transition temperature of block copolymers depends slightly on polymer structure. The derivatives of TGA curves indicate that thermal degradation occurs in one stage. The self-assembly of PMMA-b-PHEMA in aqueous solution have been investigated by fluorescence probing methods. The critical micelle concentrations are in the range 10-6 - 10-7 M. The micropolarity sensed by pyrene is higher than in aggregates formed by block copolymers based on polystyrene. Keywords: Block copolymers...

Detection of the bacterium, Xylella fastidiosa, in saliva of glassy-winged sharpshooter, Homalodisca vitripennis

RAMIREZ, Jose L.; LACAVA, Paulo T.; MILLER, Thomas A.
Fonte: UNIV ARIZONA Publicador: UNIV ARIZONA
Tipo: Artigo de Revista Científica
Português
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35.99%
Homalodisca vitripennis ( Germar) ( Hemiptera: Cicadellidae), the glassy- winged sharpshooter, is one of the most important vectors of the bacterium, Xylella fastidiosa subsp. piercei ( Xanthomonadales: Xanthomonadaceae) that causes Pierce's Disease in grapevines in California. In the present study we report a new method for studying pathogen transmission or probing behavior of H. vitripennis. When confined, H. vitripennis attempt to probe the surface of sterile containers 48 hours post- acquisition of X. f. piercei. The saliva deposited during attempted feeding probes was found to contain X. f. piercei. We observed no correlation between X. f. piercei titers in the foregut of H. vitripennis that fed on Xylella- infected grapevines and the presence of this bacterium in the deposited saliva. The infection rate after a 48 h post- acquisition feeding on healthy citrus and grapevines was observed to be 77% for H. vitripennis that fed on grapevines and 81% for H. vitripennis that fed on citrus, with no difference in the number of positive probing sites from H. vitripennis that fed on either grapevine or citrus. This method is amenable for individual assessment of X. f. piercei- infectivity, with samples less likely to be affected by tissue contamination that is usually present in whole body extracts.

Human Probing Behavior of Aedes aegypti when Infected with a Life-Shortening Strain of Wolbachia

Moreira, Luciano A.; Saig, Emad; Turley, Andrew P.; Ribeiro, José M. C.; O'Neill, Scott L.; McGraw, Elizabeth A.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 15/12/2009 Português
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Mosquitoes transmit diseases when they are actively searching for a source of blood. This so called probing behavior comprises the “searching” time, the beginning of the feeding process until the first sign of blood can be seen within the insect body. The manipulation of this behavior can have important consequences for the mosquito's ability to transmit pathogens, such as dengue virus or Plasmodium. In this study we examined the probing behavior of the main vector of dengue viruses, Aedes aegypti, when infected with an intracellular bacterium, Wolbachia pipientis. This bacterium alters the probing behavior of older mosquitoes such that they take longer to find a feeding site and longer to imbibe blood, which may make them more susceptible to human defense responses. The bacterium appears to reduce mosquito feeding success by preventing the mosquito from successfully inserting its stylet into human skin. The old age onset of reduced mosquito feeding success due to Wolbachia could selectively promote a reduction in dengue transmission.

Interação trigo-silício-inseticida na biologia e no comportamento de prova do pulgão-verde Schizaphis graminum (Rondani) (Hemiptera: Aphididae) monitorado pela técnica Electrical Penetration Graphs (EPG); Interactions wheat-silicon-insecticide in the biology and probing behavior of greenbug Schizaphis graminum (Rondani) (Hemiptera: Aphididae) monitoring "Electrical Penetration Graphs" technique (EPG)

Goussain, Marcio Marcus
Fonte: UNIVERSIDADE FEDERAL DE LAVRAS; DEN - Programa de Pós-graduação; UFLA; BRASIL Publicador: UNIVERSIDADE FEDERAL DE LAVRAS; DEN - Programa de Pós-graduação; UFLA; BRASIL
Tipo: Tese de Doutorado
Publicado em 18/08/2014 Português
Relevância na Pesquisa
36.15%
Methods of control that diminish the impact of the use of insecticides are being each praised and adopted time more in modern agriculture. Studies with silicon have demonstrated that its application can increase plant resistance to insects. This work had also objective to evaluate the effect of the silicon and the insecticide dimetoato on the probing behaviour of the greenbug S. graminum by using the technique "Electrical Penetration Graphs" (EPG). Moreover, tests with "honeydew clock" were performed and biological studies of the greenbug in plants treated with soil and foliar applications of silicon. The silicon application diminished the probing-time, the number of "honeydew" drops, the duration of the reproductive period, the longevity and the fecundity of S. graminum. The period of non-probing before the first phloem phase increased significantly with silicon application as well as the period to reach the phloem. On the other hand, the insecticide application increased xylem phase. These results demonstrate that utilization of silicon can result in the increase of wheat resistance the green-bug and that the insecticide application changed the behavior of the insect. The silicon applied could be a viable technique in the integrated pest management of aphids in wheat crop.; Métodos de controle que visam diminuir o impacto da utilização de inseticidas estão sendo cada vez mais pesquisados e adotados na agricultura moderna. Estudos com silício têm demonstrado que a sua aplicação pode aumentar o grau de resistência das plantas ao ataque de insetos. Diante disso...

Comparison of Potato virus Y and Plum Pox Virus transmission by two aphid species in relation to their probing behaviour

Fernandez-Calvino, L.; López-Abella, Dionisio; López-Moya Gómez, Juan José; Fereres, Alberto
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 4085 bytes; image/gif
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Two different aphid species,Myzus persicae (Sulzer) andHyalopterus pruni (Geoffroy) (Homoptera: Aphididae), were used to analyze their ability to transmit two different potyviruses,Potato virus Y (PVY) andPlum pox virus (PPV), to pepper (Capsicum annuum) andNicotiana benthamiana plants, respectively. In parallel experiments,M. persicae consistently transmitted both viruses with high efficiency, whereasH. pruni always failed to transmit either virus. This is in contrast to previous reports describingH. pruni as a vector of these potyviruses. Different aphid probing behavior among individual aphids of each species was obtained in electrical penetration graph (EPG) experiments performed on pepper plants. This suggested thatH. pruni did not transmit these potyviruses due to behavioral differences during probing that impeded virus acquisition and/or inoculation. It was found thatM. persicae usually makes its first probe within the first 2 min, whereasH. pruni individuals remained for more than 10 min on the plant before starting to probe. Furthermore,M. persicae individuals displayed their first intracellular puncture during the first minute of probing whereasH. pruni needed ∼ 15 min to penetrate the cell plasmalemma with their stylets. In addition...

Nonpersistent virus transmission efficiency is determined by aphid probing behavior during intracellular punctures

Collar, J. L.; Fereres, Alberto
Fonte: Entomological Society of America Publicador: Entomological Society of America
Tipo: Artículo Formato: 6080 bytes; image/gif
Português
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The probing behavior of starved and nonstarved Myzus persicae (Sulzer) on pepper plants was compared using the electrical penetration graph technique. Special attention was paid to the 1st intracellular puncture produced by the aphids, recorded as a potential drop waveform pattern. Previously fasted aphids produced potential drops with a longer phase II3 (3.6 versus 2.5 s), and typical II3 pulses were clearly visible in 89% of the records (versus only 61% for the nonstarved aphids). This ability of starved aphids to produce potential drops with a long phase II3 and its associated II3 pulses may account for the increase in potato virus Y (PVY) transmission efficiency when compared with nonstarved aphids (57 versus 4%). A new explanation to the "preacquisition starvation effect" is proposed based on our results. In a separate experiment, the early probing behavior of different aphid species [M. persicae, Aphis gossypii Glover, Rhopalosiphum padi (L.), and Sitobion avenae (F.)] on pepper plants was compared. Again, the great variability observed in the morphology and duration of phase II3 of the potential drops could be correlated with differences in transmission efficiences. Individuals from species that transmitted PVY efficiently (M. persicae and A. gossypii) usually produced pds with long II3 phases and clear II3 pulses...

Behavioral response and virus vector ability of Myzus persicae (Homoptera: Aphididae) probing on pepper plants treated with aphicides

Collar, J. L.; Avilla, C.; Duque, M.; Fereres, Alberto
Fonte: Entomological Society of America Publicador: Entomological Society of America
Tipo: Artículo Formato: 6080 bytes; image/gif
Português
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36.24%
Behavioral response of the green peach aphid, Myzus persicae (Sulzer), to 3 different insecticides (cypermethrin, pirimicarb, and imidacloprid) was assessed on pepper plants, Capsicum annuum L., using electrical monitoring of aphid probing behavior. This technique enabled us to assess stylet penetration pathways as well as cell membrane punctures (potential drops). The effect of these insecticide treatments on potato virus Y (PVY) transmission by M. persicae also was tested. Pirimicarb and imidacloprid did not significantly affect probing behavior or PVY transmission efficiency when aphids were allowed a 10-min acquisition access period on infected insecticide-treated plants. Conversely, cypermethrin affected aphid behavior as well as PVY transmission efficiency. Aphids probing on cypermethrin-treated plants produced fewer (1.7 versus 3.3) and shorter (41 versus 152 s) penetrations than those probing on untreated plants. They also produced a lower number of potential drops (1.3 versus 4.2). Moreover, cypermethrin caused a paralysis of aphids within 2.5 min of exposure to the treated plants. Aphids were not able to subsequently inoculate healthy plants. However, when the acquisition access period was shorter than 2.5 min, aphids were able to efficiently transmit PVY despite the cypermethrin treatment of the virus source plant. The possible existence of an additional deterrent effect caused by cypermethrin on M. persicae and its implications in PVY epidemiology is discussed; Peer reviewed

Behavioral and Sublethal Effects of Structurally Related Lower Terpenes on Myzus persicae

Gutiérrez, Carmen; Fereres, Alberto; Reina, Matías; Cabrera, Raimundo; González-Coloma, Azucena
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 6080 bytes; image/gif
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36.09%
The sesquiterpenes farnesol, caryophyllene oxide, and 2,10-bisaboladien-1-one (patent #9602748) and the monoterpenes citronellol and geraniol were tested for settling inhibition and chronic effects on the aphidMyzus persicae by means of an improved leaf-disk assay. Of these compounds, geraniol, famesol, and the natural bisabolene significantly inhibit settling in choice tests. Furthermore, application of the bisabolene to intactCapsicum annuum leaves did not cause phytotoxicity, but did affect the insects' probing behavior by decreasing the probing activity and the number of intracellular punctures. Both compounds significantly decreased offspring production. Of the compounds tested, the natural product bisabolene could be a promising lead for future development of aphid control agents.; This work has been supported by a grant from DGICYT (PB94-0020).; Peer reviewed

Characterization of electrical penetration graphs of Bucephalogonia xanthophis, a vector of Xylella fastidiosa in citrus

Miranda, M. P.; Fereres, Alberto; Appezzato-da-Gloria, B.; Lopes, J. R. S.
Fonte: Netherlands Entomological Society Publicador: Netherlands Entomological Society
Tipo: Artículo Formato: 1042648 bytes; application/pdf
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12 pages, and tables.; The sharpshooter Bucephalogonia xanthophis (Berg) (Homoptera: Cicadellidae) is a vector of the xylemlimited bacterium, Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner), which causes citrus variegated chlorosis. Despite the importance of citrus variegated chlorosis, the probing behavior of vectors on citrus and its implications for transmission of X. fastidiosa have not been studied. Here we studied electrical penetration graph (EPG-DC system) waveforms produced by B. xanthophis on Citrus sinensis (L.) Osbeck (Rutaceae), and their relationships with stylet activities and xylem ingestion. Electrical penetration graph waveforms were described based on amplitude, frequency, voltage level, and electrical origin of the observed traces during stylet penetration on plant tissues. The main waveforms were correlated with histological observations of salivary sheaths in plant tissues and excretion analysis, in order to determine stylet activities and their precise position. Six waveforms and associated activities are described: (S) secretion of salivary sheath and intracellular stylet pathway, (R) resting during stylet pathway, (Xc) contact of stylets with xylem vessels, (Xi) active xylem ingestion...

Probing and Feeding Behavior of Two Distinct Biotypes of Bemisia tabaci (Homoptera: Aleyrodidae) on Tomato Plant

Jiang, Y-X.; Lei, H.; Collar, J. L.; Martín, B.; Muñiz, M.; Fereres, Alberto
Fonte: Conselho Superior de Investigações Científicas Publicador: Conselho Superior de Investigações Científicas
Tipo: Artículo Formato: 458192 bytes; application/pdf
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The probing and feeding behavior of 2 biotypes (B and Q)of the sweetpotato whitefly, Bemisia tabaci (Gennadius), were monitored using the electrical penetration graph (EPG) technique on tomato, Lycopersicon esculentum (Mill) ("Riofuego"). Seven EPG waveform patterns were distinguished. B. tabaci (B biotype) showed a shorter duration of potential drop pattern (4.73±0.45s) [mean ± SE], n=125), longer time to reach the phloem (209 ± 23.42min, n=22), and more complex pathway patterns than the greenhouse whiteßy, Trialeurodes vaporariorum (Westwood). Some differences were observed in feeding behavior of the 2 B. tabaci biotypes (B and Q) tested. Interestingly, significant differences (P<0.05) were found in those parameters related with phloem events: total duration of the E(pd), E(pd)1, and E(pd)2 (P,0.01), as well as mean duration of E(pd)and E(pd)2. In addition, there also were significant differences in the total number of probes (P<0.05). The Q biotype showed fewer number of probes and a longer phloem ingestion time (pattern E(pd)2) than those from the B biotype. Hence, our results revealed a clear difference in the probing and feeding behavior between the B and the Q biotypes of B. tabaci on tomato plants.; Peer reviewed

Resistance inducing agents on the biology and probing behaviour of the greenbug in wheat; Agentes indutores de resistência na biologia e no comportamento alimentar do pulgão-verde em trigo

Pereira, Rosane Rodrigues Costa; Moraes, Jair Campos; Prado, Ernesto; Dacosta, Ronelza Rodrigues
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/08/2010 Português
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The greenbug Schizaphis graminum (Rond.) (Hemiptera: Aphididae) is one of the main pestinsects of wheat (Triticum aestivum, L.). Resistance inducing agents as silicon (Si) and acibenzolar-s-methyl (ASM) can provide some protection against insects and diseases. The effect of Si and/or ASM on the development and probing behaviour of S. graminum in wheat plants was evaluated. Wheat plants (cultivar Embrapa 22) were treated with Si (silicic acid at the rate of 1%) and acibenzolar-S-methyl (ASM) at the rate of 0.5%. The effects of these treatments on greenbugs were analyzed by development parameters, honeydew excretion and probing behavior monitored by Electrical Penetration Graphs (EPG). The development and honeydew experiments consisted of ten replications each and EPG experiment was replicated 25 times. The application of both resistance inducing agents reduced fecundity, prolonged the duration of pre-reproductive period, and decreased honeydew production. Induced resistance was localized mainly at phloem level and caused a strong reduction of phloem sap ingestion, but some effect of ASM at parenchyma/mesophyll level could not be discounted as far fewer aphids reached the sieve elements.; O pulgão-verde Schizaphis graminum (Rond.) (Hemiptera: Aphididae) é um dos principais insetos- praga da cultura do trigo (Triticum aestivum...