17 research outputs found

    Escala diagramática para quantificação da severidade de manchas em folhas de Eucalyptus globulus Labill. causadas por Teratosphaeria nubilosa (Cooke) Crous & U. Braun

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    http://dx.doi.org/10.5902/198050989296The leaf spot (Mycosphaerella leaf disease = MLD) caused by Teratosphaeria nubilosa has caused damage in eucalypt plantations in southern and southeastern Brazil. The need to assess the disease in the field to evaluate of this damage, efficiency control, evaluation of germplasm induces to the necessity of having a visual scale for evaluation of disease. The objective was to develop a diagrammatic scale for young leaves and one for adult leaves of Eucalyptus globules for MLD. To do so, the leaves collected in the field were scanned for image analysis. The damaged area, the healthy leaf area and the external area of the same scale RGB (Red, Green, Blue) were determined. Subsequently, it was determinate the levels of severity depending on the sample distribution with seven levels for young leaves and six for adult leaves. For the visual acuity test and validate the scale, the leaves were evaluated for severity, with and without scale. With this proposed scales, the assessors showed good accuracy both for young and adult leaves with R2=0,98 and R2=0,80, respectively. The importance of the development of diagrammatic scales for assessing MLD in eucalyptus must to the fact that allows quantification of the symptoms accurately and precisely.http://dx.doi.org/10.5902/198050989296A mancha foliar (mancha de micosferela) causada por Teratosphaeria nubilosa tem acarretado preju√≠zos em plantios de eucalipto na regi√£o Sul e Sudeste do Brasil. A necessidade de avaliar a doen√ßa no campo e os danos causados pela mesma, bem como a busca de formas eficientes de controle e a utiliza√ß√£o de germoplasma, leva √† necessidade em ter uma escala visual para quantifica√ß√£o da severidade da doen√ßa. O objetivo deste trabalho foi elaborar uma escala diagram√°tica com folhas jovens e com folhas adultas de Eucalyptus globulus, para avalia√ß√£o de mancha de micosferela. Para tal, as folhas coletadas em campo foram escaneadas para digitaliza√ß√£o da imagem. Determinou-se a √°rea lesionada, √°rea foliar sadia e √°rea total em escala RGB (Red, Green, Blue). Posteriormente, determinaram-se os n√≠veis de severidade em fun√ß√£o da distribui√ß√£o da amostra, sendo sete n√≠veis para folhas jovens e seis para folhas adultas. Para o teste de acuidade visual e valida√ß√£o da escala, as folhas foram submetidas √† avalia√ß√£o da severidade, com e sem escala. Com a ado√ß√£o das escalas propostas, a totalidade dos avaliadores apresentou boa acur√°cia, tanto para folhas jovens como para adultas com R2=0,98 e R2=0,80, respectivamente. A import√Ęncia da elabora√ß√£o de escalas diagram√°ticas para quantificar a severidade de mancha em eucalipto deve-se ao fato de permitir a quantifica√ß√£o dos sintomas de forma acurada e precisa

    Escala diagramática para quantificação da severidade de manchas em folhas de Eucalyptus globulus Labill. causadas por Teratosphaeria nubilosa (Cooke) Crous & U. Braun

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    The leaf spot (Mycosphaerella leaf disease = MLD) caused by Teratosphaeria nubilosa has caused damage in eucalypt plantations in southern and southeastern Brazil. The need to assess the disease in the field to evaluate of this damage, efficiency control, evaluation of germplasm induces to the necessity of having a visual scale for evaluation of disease. The objective was to develop a diagrammatic scale for young leaves and one for adult leaves of Eucalyptus globules for MLD. To do so, the leaves collected in the field were scanned for image analysis. The damaged area, the healthy leaf area and the external area of the same scale RGB (Red, Green, Blue) were determined. Subsequently, it was determinate the levels of severity depending on the sample distribution with seven levels for young leaves and six for adult leaves. For the visual acuity test and validate the scale, the leaves were evaluated for severity, with and without scale. With this proposed scales, the assessors showed good accuracy both for young and adult leaves with R2=0,98 and R2=0,80, respectively. The importance of the development of diagrammatic scales for assessing MLD in eucalyptus must to the fact that allows quantification of the symptoms accurately and precisely

    Mancha de micosferela em Eucalyptus globulus: características e ascogênese do patógeno, estrutura e composição química foliar

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    Muitas esp√©cies de eucalipto s√£o cultivadas no mundo todo e muitos pat√≥genos evolu√≠ram ou se adaptaram √° cultura, principalmente fungos, desde a fase de viveiro at√© os plantios adultos. A mancha de micosferela √© uma das principais doen√ßas e o Eucalyptus globulus uma das esp√©cies mais suscet√≠veis. O presente estudo foi iniciado a partir de isolamentos monosp√≥ricos de esp√©cies f√ļngicas associadas √† mancha de micosferela a partir de folhas e ramos de E. globulus provenientes de Bag√©-RS, Pedras Altas-RS, Botucatu-SP, Jacare√≠-SP e Itapeva-SP, que possibilitou a obten√ß√£o de 46 isolados, que foram observados quanto √† forma de germina√ß√£o e crescimento micelial. A determina√ß√£o das esp√©cies deu-se por meio de PCR com primers da regi√£o gen√īmica ITS1 e ITS4 e sequenciamento (vide cap√≠tulo 1). Como resultado, v√°rias esp√©cies foram encontradas e descritas. Mudas de E. globulus foram inoculadas pelo m√©todo da exposi√ß√£o de mudas sadias √† folhas com sintomas de Teratosphaeria nubilosa, por eje√ß√£o de asc√≥sporos, em casa de vegeta√ß√£o. Estas mudas foram avaliadas e folhas com os sintomas do fungo foram coletadas a partir da terceira semana at√© a d√©cima terceira semana da inocula√ß√£o. Para realiza√ß√£o de cortes e estudos histol√≥gicos, que permitiram observar a forma√ß√£o dos pseudot√©cios desde o seu in√≠cio tr√™s semanas ap√≥s a inocula√ß√£o, as hifas asc√≥genas dentro do pseudot√©cio ap√≥s nove semanas e a forma√ß√£o das ascas e asc√≥sporos ap√≥s 11 e 13 semanas, respectivamente (vide cap√≠tulo 2). Atrav√©s de estudos anat√īmicos, verificou-se que as folhas adultas apresentaram menor intensidade dos sintomas, o que pode estar relacionado com a compacta√ß√£o das c√©lulas do par√™nquima, enquanto que as folhas jovens apresentam espa√ßos intercelulares no par√™nquima lacunoso, no par√™nquima pali√ß√°dico e na c√Ęmara subestom√°tica...Many Eucalyptus species are grown worldwide, and many pathogens have evolved and adapted to the culture. The cultivation of eucalyptus is affected by a number of diseases. Many pathogens occur in several eucalypt species, especially fungi, from the nursery to the planting adults. The Mycosphaerella leaf disease is a major disease and Eucalyptus globulus one of the most susceptible species. This study consisted of spore isolates of fungal species associated with Mycosphaerella leaf disease from leaves and stems of E. globulus from Bage-RS, Pedras Altas-RS, Botucatu-SP, Jacare√≠-SP, Itapeva-SP, which allowed the collection of 46 isolatesm sequenced (see Chapter 1). As a result, several species were found and described. Seedlings of E.globulus were inoculated by exposure to leaves of healthy seedlings with symptoms of Teratosphaeria nubilosa, for ejection of ascospores in the greenhouse. Seedlings were evaluated, and leaves with the symptoms of the fungus were collected from the third week up to thirteenth week of inoculation. To carry out studies and histological sections, which allowed the formation of the pseudothecia from its beginning three weeks after inoculation, the formation of the ascogenous hyphae within pseudothecia after nine weeks, and the formation of asci and ascospores after 11 and 13 weeks, respectively (see Chapter 2). Through anatomical studies, it was found that if the adult leaves had a lower intensity of symptoms, which may be related to compression of the parenchyma cells, while the young leaves have intercellular spaces in the spongy parenchyma, palisade parenchyma and in substomatal chambers facilitating the formation of stroma (see Chapter 3). Essential oils of leaves and young adults, healthy and stain micosferela were extracted by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The data of chemical composition and the respective percentages... (Complete abstract click electronic access below

    Produção de basidiosporos, inibidores da germinação e patogenicidade de Puccinia pampeana Speg. a Capsicum spp

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    No presente trabalho, verificou-se a capacidade de produ√ß√£o de basidiosporos produzidos pelos teliossoros teli√≥ides de Puccinia pampeana. Avaliou-se a inibi√ß√£o da germina√ß√£o de esporos de tr√™s agentes causais de ferrugem pelas subst√Ęncias auto-inibidoras, presentes nas paredes dos teliosporos teli√≥ides, e a suscetibilidade de esp√©cies de Capsicum e tamb√©m outras solan√°ceas, como jil√≥ e berinjela. Foi constatado, que choques de temperatura (35¬ļC e 8¬ļC) por 3 horas, em seguida temperatura continua de 12¬ļC, n√£o inviabilizam os teliossoros teli√≥ides, apenas provocam diferen√ßas no in√≠cio da produ√ß√£o de basidiosporos. Quando mantidos a 12¬ļC, e com lavagens di√°rias dos soros, s√£o capazes de produzir basidiosporos por um per√≠odo de at√© 5 meses. Extratos aquosos de esporos (EAE1, EAE2, EAE3, EAE4) preparados com 20 mg de teliosporos teli√≥ides, continham quantidades de autoinibidor capazes de inibir teliosporos aecidi√≥ides de P. pampeana, e urediniosporos de Coleosporium plumierae e de Hemileia vastatrix, sendo este efeito inibidor na germina√ß√£o, comprovado mesmo ap√≥s 6 horas em contato com os extratos. Nos testes de inocula√ß√£o observou-se, que nem todas as esp√©cies dentro do g√™nero Capsicum, s√£o suscet√≠veis, pois algumas apresentaram rea√ß√£o de hipersensibilidade. Como √© o caso de C.annuum (pimenta cayenne) e C. chinense (pimenta haba√Īero), que ap√≥s a forma√ß√£o dos espermog√īnios (11 dias), aos 15 dias da inocula√ß√£o, apresentou manchas necr√≥ticas na regi√£o perif√©rica aos espermog√īnios, interrompendo a infec√ß√£o. Tamb√©m foi observada rea√ß√£o de hipersensibilidade, de forma mais moderada em C. annuum (pimenta serrano) e C. baccatum (chap√©u-de-frade) nas folhas, as hastes de ambas as esp√©cies apresentavam estruturas do fungo. Nas outras solan√°ceas inoculadas: Solanum gillo (jil√≥) e Solanum melongena (berinjela), n√£o foram...In the present work, we studied the basidiospore production capacity of telioid teliosori of Puccinia pampeana. We evaluated the spore germination inhibition of three rust causal agents by self-inhibiting substances present in the walls of telioid teliospores, as well as the susceptibility of Capsicum species and other solanaceous plants, such as jil√≥ and eggplant. It was observed that telioid teliosori submitted to temperature shocks (35¬ļC and 8¬ļC) for 3 hours and then maintained at 12¬ļC did not become unviable. The shocks only caused differences in the beginning of basidiospore production. When maintained at 12¬ļC, with the sori washed daily, they were capable of producing basidiospores for a period of up to 5 months. With regard to spore aqueous extracts (EAE1, EAE2, EAE3, EAE4) prepared with 20 mg of telioid teliospores, they contained quantities of the self-inhibitor that were capable of inhibiting P. pampeana aecidioid teliospores and Coleosporium plumierae and Hemileia vastatrix urediniospores. This inhibiting effect on germination was demonstrated even after 6 hours of contact with the extracts. In inoculation tests, it was observed that not all species within the genus Capsicum are susceptible, since some of them showed a hypersensitivity reaction, such as C. chinense (datil pepper), which, after spermogonia formation (11 days), showed necrotic spots in the peripheral region of the spermogonia at 15 days from inoculation, interrupting the infection. A milder hypersensitivity reaction was also observed in leaves of C. annuum (chili pepper) and C. baccatum (chap√©u-de-frade); the stalks of both species showed structures of the fungus. No symptoms or signs of infection were observed in other solanaceous plants inoculated - Solanum gillo (jil√≥) and Solanum melongena (eggplant) - which demonstrates the specificity of this rust to Capsicum spp.Conselho Nacional de Desenvolvimento Cient√≠fico e Tecnol√≥gico (CNPq

    Biological studies of puccina species using germinatelia

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    Despite the importance of plant pathogens belonging to the Order Pucciniales (=Uredinales), popularly called rusts, certain peculiarities of its biology is poorly known, mainly due to the difficulty of growing them in culture media and also by the lack of appropriate methodologies for the development of research. Therefore, this study was to verify the efficiency of apparatus called germinatelia to obtain data about the basidiospores production biology of different Pucciniales species. Were used in the study Puccinia pampeana, P. psidii, P. pelargonii-zonalis, P. arachidis, P. mogiphanis, P. emiliae, P. hetereospora, P. malvacearum and P. cnici-oleracei. The use of germinatelia have revealed high basidiospores production for a period up to 5 months at temperatures between 12 degrees and 21 degrees C. Furthermore, in P. malvacearum was possible to record the germination by repetition (survival strategy) in 4.5% of basidiospores produced. All species were favored to mild temperatures. These results therefore demonstrate that the use of germinatelios is efficient, assisting in obtaining data about the biology and cycles of different Puccinia species, enabling better understanding of these pathogens, resulting in management and control measures most appropriate/accurate

    Especificidade de Puccinia pampeana a cultivares de Capsicum spp. e outras solan√°ceas

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    A ferrugem de esp√©cies de Capsicum spp. (pimenta e piment√£o), √© causada pelo fungo Puccinia pampeana, pode causar perdas totais em plantios de diversas esp√©cies de Capsicum, onde preodminam temperaturas ao redor de 21¬ļC. Esta ferrugem, mesmo sendo espec√≠fica do g√™nero Capsicum, e mesmo muitas esp√©cies dentro deste g√™nero sendo suscet√≠veis, algumas apresentam rea√ß√£o de hipersensibilidade. Foi o caso de Capsicum annuum (pimenta cv. Cayenne) e C. chinense (pimenta cv. Haba√Īero), que ap√≥s a forma√ß√£o dos espermog√īnios (11 dias), apresentou manchas necr√≥ticas na regi√£o perif√©rica aos espermog√īnios, aos 15 dias ap√≥s a inocula√ß√£o, n√£o havendo evolu√ß√£o da infec√ß√£o. Tamb√©m foi observada rea√ß√£o de hipersensibilidade, de forma mais moderada em folhas C. annuum (pimenta serrano) e C. baccatum (chap√©u-de-frade). Com rela√ß√£o √†s outras solan√°ceas inoculadas (jil√≥ e berinjela) n√£o foram observados os sintomas e sinais da infec√ß√£o.The Capsicum spp. (pepper and green pepper) rust is caused by the fungus Puccinia pampeana. This is an important disease in these crops which may cause complete losses in crops of several species of Capsicum. Although specific to the genus Capsicum, and despite the fact that many species within this genus are susceptible to rust, some of them have shown a hypersensitivity reaction. That was the case with Capsicum annuum (Cayenne pepper) and C. chinense (datil pepper), which, after spermogonia formation (11 days), showed necrotic spots in the peripheral region of the spermogonia 15 days after inoculation, without evolution of the infection. A milder hypersensitivity reaction was also observed only in leaves of C. annuum (chili pepper) and C. baccatum (chap√©u-de-frade). With regard to other solanaceous plants inoculated (jil√≥ and eggplant), no symptoms or signs of infection were observed

    Ferrugem da teca (Olivea neotectonae): novas ocorrências no Brasil e revisão do nome específico

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    O agente causal da ferrugem da teca (Olivea neotectonae) vem atacando as planta√ß√Ķes de diversos pa√≠ses que possuem plantios naturais ou comerciais. Ocasiona desfolha intensa das plantas contribuindo para a redu√ß√£o da √°rea fotossint√©tica e consequentemente, a produ√ß√£o. Especialmente associado a viveiros, apresenta maior severidade em plantas com menos de 10 anos de idade. Como sintomas da infec√ß√£o s√£o observadas manchas marrons e como sinais, soros pulverulentos de cor amarelo alaranjado. em maio de 2009, estes sintomas e sinais foram observados em folhas de teca, provenientes do norte do estado do Mato Grosso, Maranh√£o, Tocantins e da regi√£o centro-oeste do estado S√£o Paulo, recebidos pelo laborat√≥rio de Patologia Florestal da FCA UNESP-Botucatu. O objetivo do presente trabalho √© fazer o registro dessas constata√ß√Ķes nos estados brasileiros e uma breve revis√£o sobre a denomina√ß√£o correta do pat√≥geno.The causal agent of rust teak (Olivea neotectonae) has attacked the teak plantations in several countries of world. It causes severe defoliation of the plants contributing to the reduction of photosynthetic area and hence the production. Especially associated with nurseries plants is more severe in plants with less than 10 years of age. The symptoms of infection are seen as brown spots and signs, serum powdery yellow-orange color. In May 2009 these symptoms and signs were observed in leaves of teak coming from the northern state of Mato Grosso, Maranh√£o, Tocantins and the Midwest state of S√£o Paulo, received by the laboratory of Forest Pathology of FCA-UNESP Botucatu. The aim of this work is to record these observations in the Brazilian states and a brief review on the correct designation of the pathogen
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