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Cigarrinhas potenciais vetoras (Hemiptera: Cercopidae e Cicadellidae) e plantas infestantes associadas à epidemiologia da escaldadura das folhas da ameixeira / Potential hopper vectors (Hemiptera: Cercopidae and Cicadellidae) and weeds associated with the epidemiology of Plum Leaf ScaldGraner, Luiza Silva 07 November 2014 (has links)
A Escaldadura das Folhas da Ameixeira (EFA) é uma das principais doenças que prejudicam a produção de ameixas no Brasil. Ela é causada pela bactéria Xylella fastidiosa (Wells) cujos potenciais vetores são cigarrinhas (Hemiptera: Cercopidae e Cicadellidae, Cicadellinae). Sabe-se que existem diversas espécies de cicadelídeos e cercopídeos em pomares de ameixeira, mas faltam informações sobre as plantas hospedeiras desses insetos e sua importância epidemiológica. Esta pesquisa teve por objetivo associar as cigarrinhas potenciais vetoras com as plantas de ameixeira e com plantas infestantes da vegetação de cobertura dos pomares. Para tal, realizaram-se amostragens de cigarrinhas em três pomares de ameixeira no município de Paranapanema-SP, no período de setembro/2012 a abril/2013, usando-se três métodos distintos: a) rede de varredura em plantas infestantes; b) armadilhas adesivas amarelas colocadas na copa das ameixeiras a 0,5 e 2 m acima do solo; e c) amostragens visuais em ameixeiras e certas plantas infestantes. As cigarrinhas coletadas foram triadas e identificadas em laboratório e os resultados obtidos foram submetidos à análise faunística. Para verificar se as plantas infestantes eram hospedeiras da X. fastidiosa, experimentos de inoculação mecânica foram feitos para tentar estabelecer infecção pela bactéria nas plantas de Bidens pilosa L., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. e Lantana camara L. Após meses da inoculação, as plantas foram testadas por PCR e isolamento primários para detectar a infecção por X. fastidiosa. Avaliou-se, também, a ocorrência de transmissão de X. fastidiosa de ameixeiras paras plantas infestantes, por cigarrinhas sabidamente vetoras, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). Nas amostragens com rede de varredura, encontraram-se 72 espécies de cigarrinhas associadas às plantas infestantes dos pomares de ameixeiras, pertencentes às famílias Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae e Membracidae. As cigarrinhas foram observadas em um total de oito espécies herbáceas de dicotiledôneas e sete monocotiledôneas. As plantas infestantes que abrigam maiores números de cigarrinha são Paspalum notatum Flügge, Parthenium hysterophorus L. e Raphanus sativus L. Dentre as espécies com potencial de transmitir X. fastidiosa, o cercopídeo Deois schach (Fabricius) e o cicadelíneo Plesiommata corniculata Young predominaram nas plantas infestantes dos pomares de ameixeira, podendo ter um papel chave em uma eventual disseminação primária de X. fastidiosa dessas plantas para ameixeira. Os cicadelíneos Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) predominaram em capturas com armadilhas adesivas amarelas na copa das ameixeiras, o que sugere sua participação na disseminação secundária de X. fastidiosa entre árvores de ameixeira. O. facialis foi visualizada nos ramos de ameixeiras e de Lantana camara L. As plantas infestantes Solanum americanum Mill e L. camara permitem colonização por X. fastidiosa após inoculação mecânica. A cigarrinha Sibovia sagata (Signoret) é capaz de transmitir X. fastidiosa de ameixeira para S. americanum. / Plum Leaf Scald (PLS) is one of the major diseases that impair the production of plums in Brazil, caused by the xylem-limited bacterium Xylella fastidiosa (Wells), whose potential vectors in plums are sharpshooter leafhoppers (Hemiptera: Cicadellidae, Cicadellinae) and spittlebugs (Hemiptera: Cercopidae). A number of leafhoppers and and spittlebugs have been reported in Brazilian plum orchards, but their host plants and role in PLS epidemiology are largely unknown. The goal of this research was to investigate the association of potential hopper vectors with plum trees and weedy plants in the ground vegetation of orchards, in order to determine key vector species and weeds involved in PLS epidemiology. Therefore, a hopper survey was carried out in three plum orchards in the municipality of Paranapanema, SP, from September/2012 to April/2013, using three sampling methods: a) sweep net on weed species of the ground vegetation; b) yellow sticky cards placed on the plum canopy at 0.5 and 2 m above ground; and c) visual inspections of plum trees and some weeds. The collected hoppers were sorted and identified in the laboratory, and the data were submitted to faunistic analysis. To check if the weeds were hosts of plum strains of X. fastidiosa, bacterial suspensions were mechanically inoculated in Bidens pilosaL., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. Lantana camara L. The plants were assayed for infection of X. fastidiosa by PCR and culture at 2 months after inoculation. Transmission assays of X. fastidiosa from plum to weeds were carried out using two sharpshooter vectors, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). The sweep net samplings revealed 72 species of seven hopper families (Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae and Membracidae) associated with eight dicotyledoneous and seven monocotyledoneous weeds in the ground vegetation, with prevalence of Cicadellidae and Cercopidae. Among the potential hopper vectors, the spittlebug Deois schach (Fabricius) and the sharpshooter Plesiommata corniculata Young were predomimant species on the weed species, suggesting that they may play a key role in a possible primary spread of X. fastidiosa from weeds to plum. Paspalum notatum Flügge, Parthenium hysterophorus L. and Raphanus sativus L. were the weed species with the largest hopper populations. The sharpshooters Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) were prevalent species trapped by the yellow sticky cards on the plum canopy, indicating that they may be involved in secondary spread of X. fastidiosa between plum trees in that region. O. facialis was visually detected on branches of plum trees and on the weed Lantana camara L. The weeds Solanum americanum Mill e L. camara allow colonization by X. fastidiosa after mechanical inoculation.The sharpshooter Sibovia sagata (Signoret) transmitted X. fastidiosa from plum to S. americanum.
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Plant-arthropod interactions : domatia and mites in the genus Coprosma (Rubiaceae)O'Connell, Dean Michael, n/a January 2009 (has links)
Plant-based defence mutualisms involve aspects of plant morphology that influence the performance of plant parasites, their natural enemies and trophic interactions. Leaf domatia, small indentations on the underside of leaves, can be structurally complex, and are often inhabited by potentially beneficial mites and other arthropods. Plant morphological traits such as domatia that enhance mutualistic relationships may result in increased plant growth rates, and reproductive success. New Zealand supports ~60 plant species that have domatia, the most speciose genus being Coprosma. The aim of this thesis was to examine factors that affect the production of leaf domatia and their relationship with foliar mite assemblages. The three main objectives of this thesis are: First, to investigate the production of foliar domatia and their susceptibility to limited resources, particularly to carbon availability. Second, to test if domatia are inducible structures during leaf ontogeny in the presence of foliar mites and/or fungi. Finally, to explore the effect of domatia availability on foliar mite assemblages on leaves with and without resident mites. This thesis tested the stated objectives using C. lucida, C. ciliata, C. foetidissima and C. rotundifolia, with a combination of field investigations and controlled manipulative experiments. The cost of domatia production was investigated using two field surveys and two controlled experiments. Under natural conditions the relationship between leaf morphology and domatia were measured in situ and across an altitudinal gradient. The experimental manipulations used carbon and nutrient stress, induced by temperature, light and fertilizer application. The second objective was experimentally tested under field conditions by manipulating foliar mites and fungal densities on C. rotundifolia. The third objective was investigated by manipulating domatia availability on C. lucida shrubs across three different vegetation types. Under field conditions, the number of domatia per leaf was associated with leaf morphology in C. lucida and C. foetidissima, but not C. rotundifolia. Foliar carbon showed a positive, but weak association with domatia production in C. foetidissima and C. ciliata. Altitudinal induced-carbon stress on domatia production was ambiguous. Domatia production in C. foetidissima was positively associated to altitude in field survey (1), and negatively associated in the second survey, with no correlation found between carbon and altitude. Experimental C. rotundifolia shrubs held under elevated night-time temperatures showed a 2.5 fold increase in respiration, a 34% to 91% decrease in daily carbon gain, and 38% decrease in domatia per leaf mass. Domatia production showed no significant differences under nutrient stress. The results showed little evidence to support a role for induction of domatia. Domatia production in new leaves was similar across all experimental treatments. Diverse vegetation types supported 60% higher mite species. Leaves with domatia supported ~22 to 66% higher mite densities, greater colonisation success and more diverse mite assemblages, than those without domatia. In the pastoral vegetation, the absence of predatory mites on experimental shrubs resulted in no differences in fungivorous mite densities regardless of domatia availability. Plant investment in foliar domatia appears associated with the number of available sites on the leaf under field conditions. The role of carbon availability during leaf ontogeny suggests a complex and highly variable association with domatia production. Domatia are constitutive defence structures that influence mite assemblages, mediating both beneficial and antagonistic relationships. This thesis concludes that domatia are in part, carbon-based non-inducible structures that influence mite assemblages, plant-mite and mite-mite interactions, and increase the probability of successful colonisation.
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Potential for using insects to guide the search for medicinally-active chemical compounds in plantsRaudsepp-Hearne, Ciara January 2003 (has links)
This thesis investigates the possibility of using aposematic insects as guides to plants that contain pharmacologically-active compounds. Plants were monitored within national parks in the Republic of Panama over a period of six months and all insects feeding on them were collected and raised in captivity. The insects were then extracted and analyzed to determine how they were treating toxic chemical compounds in their host plant. Two principal plants were investigated with their associated insects: (1) Vismia baccifera and (2) Mikania guaco. One generalist and one specialist Lepidopteran species were found to sequester vismione B from their host plant Vismia baccifera, a cytotoxic compound active against three cancer cell lines. Two specialist Coleopterans were found to sequester the novel compound Guacanone, isolated by the primary author from the vine Mikania guaco and active against Trypanosoma cruzi, the causative agent of Chagas' disease. A generalist Coleopteran was found to not sequester this compound. (Abstract shortened by UMI.)
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Induction of maize wallaby ear disease by Cicadulina bimaculata and its incidental infection by leafhopper A virus / by Felix OforiOfori, Felix January 1984 (has links)
Bibliography: leaves 62-64 / iii, 64 leaves, [16] plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Pathology, 1985
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Interactions of potato virus A with host plants : recombination, gene silencing and non-hypersensitive resistance /Gammelgård, Elin, January 2007 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 3 uppsatser.
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Trivial movements and redistribution of polyphagous insect herbivores in heterogeneous vegetation /Hannunen, Salla, January 2003 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.
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Moscas-das-frutas (Diptera: Tephritidae): diversidade, hospedeiros e parasitóides em áreas nativa e cultivadas na região de Viçosa; Minas Gerais, Brasil / Fruit flies (Diptera: Tephritidae): diversity, hosts and parasitoids in the native area and cultivated in region of Viçosa, Minas Gerais, BrazilPirovani, Victor Dias 21 July 2011 (has links)
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Previous issue date: 2011-07-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study shows the diversity of species of tephritid flies, their parasitoids and hosts in the region of Viçosa, Minas Gerais, located in the Zona da Mata Mineira. McPhail traps containing hydrolyzed protein, were installed in orchards with diverse species of fruit trees and a nature reserve, the Atlantic forest, forest known as the Mata do Paraíso. In addition, collections were made periodically cultivated and wild fruits in the region. Were obtained in 21 species of tephritid collections: Ceratitis capitata (Wied.), Anastrepha bahiensis Lima, A. barbiellinii Lima, A. bezzii Lima, A. bistrigata Bezzi, A. dissimilis Stone, A. distincta Greene, A. fraterculus (Wied.), A. furcata Lima, A. grandis (Macquart), A. leptozona Hendel, A. manihoti Lima, A. minensis Lima, A. montei Lima, A. obliqua (Macquart), A. pseudoparallela (Loew), A. pickeli Lima, A. serpentina (Wied.) and A. sororcula Zucchi, and two new species of Anastrepha. Deposited at the Regional Museum of Entomology (UFVB) found five species of tephritid A. connexa Lima, A. consobrina (Loew), A. kuhlmanni Lima, A. turpiniae Stone and A. xanthochaeta Hendel. 39 species of wild and 22 cultivated plant families sampled, we obtained C. capitata, A. bezzii, A. fraterculus, A. grandis, A. obliqua and A. sororcula. Parasitoids were also collected: Braconidae - Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, Utetes anastrephae (Viereck) Figitidae - Aganaspis pelleranoi (Brèthes) and Pteromalidae - Sycophila sp.1, Sycophila sp.2, Torymus sp. and Pteromalidae sp.3. A taxonomic key for identification of species collected in Viçosa region is presented. An analysis for the fauna of Tephritidae species collected in the region of Viçosa, Minas Gerais. Assessing the population dynamics of three species was also performed, taking into account the influence of temperature, relative humidity and rainfall in addition to the dominance of these survey sites. Through this study added 19 species of fruit flies in Viçosa, Minas Gerais, bringing to 32 species of tephritid in Minas Gerais. Anastrepha barbiellinii, A. connexa, A. consobrina, A. furcata, A. kuhlmanni, A. leptozona and A. xanthochaeta were found first for the state and two new species of Anastrepha findings. Anastrepha fraterculus was the most frequent species in the samples of infected hosts and first observed occurrence in Lauraceae, Solanaceae Siparunaceae and in Brazil. The association of A. obliqua with tangerine and Ponkan cambucá and A. fraterculus with sweet cherry and passion fruit was also first observed through this study. The four species of parasitoids the Pteromalidae family, Sycophila sp.1, Sycophila sp.2, Torymus sp and a fourth species of Pteromalidae not yet identified, are new records for the state, passing 12 species of parasitoids of fruit flies in Minas Gerais. The population fluctuation of Anastrepha fraterculus and Ceratitis capitata in the region of Viçosa was influenced by temperature. Anastrepha minensis population fluctuation was influenced by temperature and precipitation. Fruticultura/Campus and Fruticultura/Fundão were more similar environments for the presence and absence of species of fruit flies (43%) while the small farm the environment was less similarity in terms of presence and absence of species (31 %). / Este estudo apresenta a diversidade de espécies de tefritídeos, seus parasitóides e hospedeiros na região de Viçosa, Minas Gerais, localizada na Zona da Mata Mineira. Armadilhas do tipo McPhail, contendo proteína hidrolisada, foram instaladas em pomares com espécies diversificadas de fruteiras e em uma reserva natural, remanescente da Mata Atlântica, conhecida como Mata do Córrego do Paraíso. Além disso, foram feitas coletas periódicas de frutos cultivados e silvestres na região. Foram obtidas 21 espécies de tefritídeos nas coletas: Ceratitis capitata (Wied.), Anastrepha bahiensis Lima, A. barbiellinii Lima, A. bezzii Lima, A. bistrigata Bezzi, A. dissimilis Stone, A. distincta Greene, A. fraterculus (Wied.), A. furcata Lima, A. grandis (Macquart), A. leptozona Hendel, A. manihoti Lima, A. minensis Lima, A. montei Lima, A. obliqua (Macquart), A. pseudoparallela (Loew), A. pickeli Lima, A. serpentina (Wied.) e A. sororcula Zucchi, além de duas novas espécies de Anastrepha. Depositadas no Museu Regional de Entomologia (UFVB) foram encontradas cinco espécies de tefritídeos: A. connexa Lima, A. consobrina (Loew), A. kuhlmanni Lima, A. turpiniae Stone e A. xanthochaeta Hendel. Das 39 espécies silvestres e cultivadas de 22 famílias botânicas amostradas, obtiveram-se C. capitata, A. bezzii, A. fraterculus, A. grandis, A. obliqua e A. sororcula. Foram coletados também os parasitóides: Braconidae - Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Opius bellus Gahan, Utetes anastrephae (Viereck); Figitidae - Aganaspis pelleranoi (Brèthes); e Pteromalidae - Sycophila sp.1, Sycophila sp.2, Torymus sp. e Pteromalidae sp.3. Uma chave taxonômica para a identificação das espécies coletadas na região de Viçosa é apresentada. Foi realizada uma análise faunística para as espécies de Tephritidae coletados na região de Viçosa, Minas Gerais. A avaliação da flutuação populacional de três espécies também foi realizada, levando em conta a influência da temperatura, umidade relativa e precipitação pluviométrica, além da dominância destas para as áreas amostradas. Através deste estudo foram acrescentadas 19 espécies de moscas-das-frutas em Viçosa, Minas Gerais, elevando assim para 32 espécies de tefritídeos em Minas Gerais. Anastrepha barbiellinii, A. connexa, A. consobrina, A. furcata, A. kuhlmanni, A. leptozona e A. xanthochaeta foram constatadas pela primeira vez para o estado e duas espécies novas de Anastrepha descobertas. Anastrepha fraterculus foi a espécie mais frequente nas amostras de hospedeiros infestados e observada pela primeira vez a sua ocorrência em Lauraceae, Siparunaceae e Solanaceae no Brasil. A associação de A. obliqua com tangerina Ponkan e cambucá e de A. fraterculus com acerola e maracujá-doce também foi observada pela primeira vez por meio deste estudo. As quatro espécies de parasitóides da família Pteromalidae, Sycophila sp.1, Sycophila sp.2, Torymus sp e uma quarta espécie de Pteromalidae ainda não identificada, são novas ocorrências para o estado, passando para 12 espécies de parasitóides de moscas-das- frutas em Minas Gerais. A flutuação populacional de Anastrepha fraterculus e Ceratitis capitata na região de Viçosa foi influenciada pela temperatura. Anastrepha minensis teve a flutuação populacional influenciada pela temperatura e precipitação. Fruticultura/Campus e Fruticultura/Fundão foram os ambientes mais similares quanto à presença e ausência de espécies de moscas-das- frutas (43%) enquanto o Sítio foi o ambiente com menor similaridade quanto à presença e ausência de espécies (31%).
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Larvas de Geometridae (Lepidoptera) e seus parasitoides em sub-bosque nativo na Universidade Federal de São Carlos, Campus São Carlos, Estado de São PauloGeraldo, Mariana 10 November 2011 (has links)
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Previous issue date: 2011-11-10 / Financiadora de Estudos e Projetos / Geometridae larvae and their parasitoids were surveyed in a understory at Universidade Federal de São Carlos, Campus São Carlos, SP. Larvae were colected among April 2009 to April 2010, with an entomological umbrella in 18 native species plants. It obtained 863 larvae including 46 species and 24 genera belong to majority the Ennominae. The Larentiinae and Sterrhinae subfamilies were also represented for Eois and Cyclophora, respectively. The Ennominae genus obtained were: Certima, Glena, Herbita, Hymenomima, Iridopsis, Ischnopteris, Isochromodes, Lomographa, Macaria, Melanolophia, Microgonia, Microxydia, Nematocampa, Oxydia, Patalene, Pero, Phyllodonta, Physocleora, Prochoerodes, Sabulodes, Thyrinteina and Trotopera. Macaria rigidata was the more abundant species which represented 31%. It recorded 174 parasitized larvae from which 337 parasitoids emerged. They are distributed among Braconidae, Ichneumonidae, Eulophidae (Hymenoptera) and Diptera, with Hymenoptera predominance. The obtained parasitoids were: Diolcogaster, Protapanteles, Glyptapanteles, Aleiodes, (Braconidae), Casinaria, Charops, Cryptophion, Diradops, Dusona, Jomine, Neotheronia, Podogaster, Polycyrtus, Mesochorinae (Ichneumonidae), Euplectrus (Eulophidae) and Tachinidae (Diptera). It recorded new parasitoids species of the genus: Diradops, Jomine and Neotheronia (Hymenoptera, Ichneumonidae). Geometridae larvae were present throughout the collection period and had increased occurrence at the end of rainy season. / Foi realizado um levantamento de larvas de Geometridae e de seus parasitoides em um subbosque localizado na Universidade Federal de São Carlos, Campus São Carlos, SP. As larvas foram coletadas, no período de abril de 2009 a abril de 2010, por meio de guarda-chuva entomológico em 18 espécies de plantas nativas. Foram coletadas 863 larvas incluindo 46 espécies e 24 gêneros pertencentes na maioria aos Ennominae. As subfamílias Larentiinae e Sterrhinae foram também representadas, respectivamente com os gêneros Eois e Cyclophora. Os gêneros de Ennominae obtidos foram: Certima, Glena, Herbita, Hymenomima, Iridopsis, Ischnopteris, Isochromodes, Lomographa, Macaria, Melanolophia, Microgonia, Microxydia, Nematocampa, Oxydia, Patalene, Pero, Phyllodonta, Physocleora, Prochoerodes, Sabulodes, Thyrinteina e Trotopera. A espécie mais abundante foi Macaria rigidata que representou 31%. Foram registradas 174 larvas parasitadas das quais emergiram 337 parasitoides distribuídos em Braconidae, Ichneumonidae, Eulophidae (Hymenoptera) e Diptera, com a predominância de Hymenoptera. Os parasitoides obtidos foram: Diolcogaster, Protapanteles, Glyptapanteles, Aleiodes, (Braconidae), Casinaria, Charops, Cryptophion, Diradops, Dusona, Jomine, Neotheronia, Podogaster, Polycyrtus, Mesochorinae (Ichneumonidae), Euplectrus (Eulophidae) e Tachinidae (Diptera). Foram registradas novas espécies de parasitoides dos gêneros: Diradops, Jomine e Neotheronia (Hymenoptera, Ichneumonidae). As larvas de Geometridae estiveram presentes em todo o período de coleta e apresentaram maior ocorrência no final do período chuvoso.
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Cigarrinhas potenciais vetoras (Hemiptera: Cercopidae e Cicadellidae) e plantas infestantes associadas à epidemiologia da escaldadura das folhas da ameixeira / Potential hopper vectors (Hemiptera: Cercopidae and Cicadellidae) and weeds associated with the epidemiology of Plum Leaf ScaldLuiza Silva Graner 07 November 2014 (has links)
A Escaldadura das Folhas da Ameixeira (EFA) é uma das principais doenças que prejudicam a produção de ameixas no Brasil. Ela é causada pela bactéria Xylella fastidiosa (Wells) cujos potenciais vetores são cigarrinhas (Hemiptera: Cercopidae e Cicadellidae, Cicadellinae). Sabe-se que existem diversas espécies de cicadelídeos e cercopídeos em pomares de ameixeira, mas faltam informações sobre as plantas hospedeiras desses insetos e sua importância epidemiológica. Esta pesquisa teve por objetivo associar as cigarrinhas potenciais vetoras com as plantas de ameixeira e com plantas infestantes da vegetação de cobertura dos pomares. Para tal, realizaram-se amostragens de cigarrinhas em três pomares de ameixeira no município de Paranapanema-SP, no período de setembro/2012 a abril/2013, usando-se três métodos distintos: a) rede de varredura em plantas infestantes; b) armadilhas adesivas amarelas colocadas na copa das ameixeiras a 0,5 e 2 m acima do solo; e c) amostragens visuais em ameixeiras e certas plantas infestantes. As cigarrinhas coletadas foram triadas e identificadas em laboratório e os resultados obtidos foram submetidos à análise faunística. Para verificar se as plantas infestantes eram hospedeiras da X. fastidiosa, experimentos de inoculação mecânica foram feitos para tentar estabelecer infecção pela bactéria nas plantas de Bidens pilosa L., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. e Lantana camara L. Após meses da inoculação, as plantas foram testadas por PCR e isolamento primários para detectar a infecção por X. fastidiosa. Avaliou-se, também, a ocorrência de transmissão de X. fastidiosa de ameixeiras paras plantas infestantes, por cigarrinhas sabidamente vetoras, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). Nas amostragens com rede de varredura, encontraram-se 72 espécies de cigarrinhas associadas às plantas infestantes dos pomares de ameixeiras, pertencentes às famílias Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae e Membracidae. As cigarrinhas foram observadas em um total de oito espécies herbáceas de dicotiledôneas e sete monocotiledôneas. As plantas infestantes que abrigam maiores números de cigarrinha são Paspalum notatum Flügge, Parthenium hysterophorus L. e Raphanus sativus L. Dentre as espécies com potencial de transmitir X. fastidiosa, o cercopídeo Deois schach (Fabricius) e o cicadelíneo Plesiommata corniculata Young predominaram nas plantas infestantes dos pomares de ameixeira, podendo ter um papel chave em uma eventual disseminação primária de X. fastidiosa dessas plantas para ameixeira. Os cicadelíneos Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) predominaram em capturas com armadilhas adesivas amarelas na copa das ameixeiras, o que sugere sua participação na disseminação secundária de X. fastidiosa entre árvores de ameixeira. O. facialis foi visualizada nos ramos de ameixeiras e de Lantana camara L. As plantas infestantes Solanum americanum Mill e L. camara permitem colonização por X. fastidiosa após inoculação mecânica. A cigarrinha Sibovia sagata (Signoret) é capaz de transmitir X. fastidiosa de ameixeira para S. americanum. / Plum Leaf Scald (PLS) is one of the major diseases that impair the production of plums in Brazil, caused by the xylem-limited bacterium Xylella fastidiosa (Wells), whose potential vectors in plums are sharpshooter leafhoppers (Hemiptera: Cicadellidae, Cicadellinae) and spittlebugs (Hemiptera: Cercopidae). A number of leafhoppers and and spittlebugs have been reported in Brazilian plum orchards, but their host plants and role in PLS epidemiology are largely unknown. The goal of this research was to investigate the association of potential hopper vectors with plum trees and weedy plants in the ground vegetation of orchards, in order to determine key vector species and weeds involved in PLS epidemiology. Therefore, a hopper survey was carried out in three plum orchards in the municipality of Paranapanema, SP, from September/2012 to April/2013, using three sampling methods: a) sweep net on weed species of the ground vegetation; b) yellow sticky cards placed on the plum canopy at 0.5 and 2 m above ground; and c) visual inspections of plum trees and some weeds. The collected hoppers were sorted and identified in the laboratory, and the data were submitted to faunistic analysis. To check if the weeds were hosts of plum strains of X. fastidiosa, bacterial suspensions were mechanically inoculated in Bidens pilosaL., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. Lantana camara L. The plants were assayed for infection of X. fastidiosa by PCR and culture at 2 months after inoculation. Transmission assays of X. fastidiosa from plum to weeds were carried out using two sharpshooter vectors, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). The sweep net samplings revealed 72 species of seven hopper families (Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae and Membracidae) associated with eight dicotyledoneous and seven monocotyledoneous weeds in the ground vegetation, with prevalence of Cicadellidae and Cercopidae. Among the potential hopper vectors, the spittlebug Deois schach (Fabricius) and the sharpshooter Plesiommata corniculata Young were predomimant species on the weed species, suggesting that they may play a key role in a possible primary spread of X. fastidiosa from weeds to plum. Paspalum notatum Flügge, Parthenium hysterophorus L. and Raphanus sativus L. were the weed species with the largest hopper populations. The sharpshooters Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) were prevalent species trapped by the yellow sticky cards on the plum canopy, indicating that they may be involved in secondary spread of X. fastidiosa between plum trees in that region. O. facialis was visually detected on branches of plum trees and on the weed Lantana camara L. The weeds Solanum americanum Mill e L. camara allow colonization by X. fastidiosa after mechanical inoculation.The sharpshooter Sibovia sagata (Signoret) transmitted X. fastidiosa from plum to S. americanum.
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Efeito de maize bushy stunt phytoplasma na sobrevivência de Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) sobre milho e plantas infestantes / Effect of maize bushy stunt phytoplasma on Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae) survival on corn and weedsAnderson Ramos 22 January 2016 (has links)
O milho (Zea mays L.) é uma cultura de grande importância para o agronegócio brasileiro, que enfrenta diversos problemas fitossanitários. Dentre as doenças destaca-se o enfezamento vermelho, que está associado ao molicute fitopatogênico, \'maize bushy stunt phytoplasma\' (MBSP). Este fitoplasma é transmitido por um grupo restrito de cicadelídeos (Hemiptera: Cicadellidae), constituído principalmente por espécies do gênero Dalbulus; no Brasil é relatada a presença de apenas uma espécie vetora, a cigarrinha-do-milho, Dalbulus maidis (DeLong & Wolcott). A cigarrinha-do-milho possui profunda associação e coevolução com o milho, sendo considerada específica dessa cultura. No México há relatos de D. maidis se desenvolvendo em espécies selvagens do gênero Zea e Tripsacum. Mas no Brasil a única planta hospedeira conhecida de D. maidis é o milho. Portanto, não se sabe como esta cigarrinha, assim como o fitoplasma por ela transmitido, sobrevivem ao longo período de entressafra que ocorre em algumas regiões brasileiras. Estudos têm demonstrado que a presença de fitopatógenos na planta e nos insetos e as alterações por eles causadas na fisiologia dos mesmos, podem melhorar desempenho biológico do inseto vetor. No México, MBSP é altamente patogênico a outras espécies de cigarrinhas do gênero Dalbulus que se alimentam no milho e competem com D. maidis. Considerando-se que no Brasil outras espécies de cigarrinhas apresentam pequenas populações em milho, postulase que este fitoplasma as afete negativamente, reduzindo sua capacidade de competição com D. maidis. O presente trabalho investigou possíveis plantas hospedeiras alternativas do inseto e do fitoplasma, outros possíveis vetores do MBSP, e o efeito do fitoplasma na sobrevivência de D. maidis e em alguns parâmetros biológicos desse vetor e do cicadelídeo Agallia albidula Uhler, espécie não vetora, presente na vegetação espontânea da cultura do milho. Dez espécies de plantas daninhas em milharais foram submetidas à inoculação de MBSP com adultos infectivos de D. maidis, mas em nenhuma delas foi detectada a infecção pelo fitoplasma, indicando que o fitoplasma possui alta especificidade em relação a plantas hospedeiras. Duas espécies de cicadelídeos comuns na vegetação rasteira de cultivos de milho, A. albidula e Planicephalus flavicosta (Stål) foram testadas como vetores de MBSP, e nenhuma delas foi capaz de transmitir o patógeno para o milho, indicando que a especificidade de vetores também é elevada. A infecção de D. maidis por MBSP afetou negativamente a sobrevivência de adultos deste inseto vetor. Por outro lado, plantas de milho infectadas por MBSP estimularam a oviposição das cigarrinhas D. maidis e A. albidula. Entretanto, a sobrevivência de ninfas de A. albidula foi muito baixa tanto em plantas sadias quanto em plantas infectadas pelo fitoplasma, indicando que o milho, independentemente do fitoplasma, não é um bom hospedeiro para desenvolvimento de A. albidula. / Corn (Zea mays L.) is an important crop for Brazilian agribusiness, but it is affected by various pests and diseases. A stunting disease associated with the phytopathogenic mollicute, maize bushy stunt phytoplasma (MBPS), is a one of the main problems. This phytoplasma is transmitted by a narrow range of leafhoppers (Hemiptera: Cicadellidae), mainly in the genus Dalbulus. In Brazil, the only known vector is the corn leafhopper, Dalbulus maidis (DeLong & Walcott). The corn leafhopper has a deep association and co-evolution with corn, and it is thought to be specific to this crop. In Mexico there are reports of D. maidis developing on wild species of Zea and Tripsacum. Because corn is the only known host of D. maidis in Brazil, it is unknown how this leafhopper and MBSP survive the long corn off-season that occurs in some Brazilian growing regions. Studies have shown that the presence of pathogens in plants and insects and the physiological changes caused by them can improve the biological performance of insect vectors. In Mexico, MBSP is highly pathogenic to some Dalbulus species that feed on corn and compete with D. maidis. Considering that in Brazil other leafhopper species have small populations in corn, it is postulated that MBSP may negatively affect them and reduce their ability to compete with D. maidis. The current study investigated possible alternative host plants of MBSP and D. maidis, other possible leafhopper vectors of MBSP and the effects of the phytoplasma on D. maidis survival and in some biological parameters of this vector and of Agallia albidula Uhler, a non-vector leafhopper present in the weedy vegetation of corn fields. Ten weed species commonly present in corn fields were inoculated with MBSP by infective adults of D. maidis, but none of them became infected with the phytoplasma, suggesting that MBSP has high host plant specificity. Two leafhopper species that inhabit the weedy vegetation of corn fields, A. albidula e Planicephalus flavicosta (Stål), were tested as vectors of MBSP, but none of them was able to transmit the pathogen to corn, indicating that the vector specificity of this phytoplasma is also high. Infection of D. maidis by MBSP negatively affected adult survival. On the other hand, infection of corn plants by MBSP induced higher oviposition by D. maidis and A. albidula. However, the survival of A. albidula nymphs was very low not only on infected plants, but also on healthy corn plants, indicating corn is not a suitable developmental host for A. albidula, regardless of the phytoplasma infection.
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