Etiologia, inoculação e escala diagramática no patossistema Colletrichum spp. x cafeeiro
Data
2014-02-26
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Editor
Universidade Federal de Lavras
Resumo
Conduziu-se este trabalho, com os objetivos de verificar a localização do C. gloeosporioides patogênico no caule; verificar a melhor metodologia de inoculação do C. gloeosporioides em folha e em ramo; construir e validar uma escala diagramática para avaliação da severidade da mancha manteigosa em folhas de cafeeiro e verificar quais nutrientes minerais e seus níveis nas lesões de mancha manteigosa. Os isolados foram obtidos da folha, do pecíolo e do ramo plagiotrópico que foi fragmentado em 10 pedaços. Após o isolamento, foi verificada a porcentagem de isolados de Colletotrichum spp. Para avaliar o melhor método de inoculação em folha, mudas foram inoculadas com cinco concentrações e seis tratamentos. Para avaliar o melhor método de inoculação em caule, o internódio terminal foi inoculado com 6 tratamentos. Para a construção e validação da escala, foram coletadas folhas, determinadas a severidade real, definidos os limites, construída a escala e validada por sete avaliadores. Para avaliar a constituição química das lesões fragmentos de folhas de cafeeiro contendo tecido sintomático e assintomático, foram desidratados, recobertos com carbono e submetidos à microanálise de raios-X. O C. gloeosporioides causador da mancha manteigosa coloniza o ramo do cafeeiro desde o pecíolo até a inserção do ramo plagiotrópico com o ortotrópico. O melhor método de inoculação em folha foi o que utilizou o ferimento por bombril. A melhor concentração de suspensão foi a de 4x10 6 conídios/mL. O melhor método de inoculação em caule foi o de inserção de palito colonizado pelo fungo. Utilizando a escala proposta, os avaliadores apresentaram melhores níveis de acurácia, precisão, reprodutibilidade e repetibilidade. Quanto à constituição química, maior teor de K foi encontrado no tecido assintomático em torno da lesão, decrescendo em direção ao tecido sintomático.
The objectives of this work were to: verify the location of the pathogenic C. gloeosporioides on the stem; verify the best methodology for C. gloeosporioides inoculation on leaf and branch; construct and validate a diagrammatic scale to evaluate the severity of the blister spot on coffee leaves; and verify which mineral nutrients and their levels are present on the blister spot. The isolates were obtained from the leaves, petiole and plagiotropic branch, which was fragmented into 10 pieces. After isolation, the percentage of Colletotrichum spp. isolates was verified. To evaluate the best inoculation method in seedling leaves, the same were inoculated with five concentrations and six treatments. To evaluate the best inoculation method in the stem, the terminal internode was inoculated with six treatments. To construct and validate the scale, leaves were collected, and seven evaluators determined the real severity, defined the limits and constructed and validated the scale. To evaluate the chemical constitution of the lesions of coffee leaves containing symptomatic and asymptomatic tissue, the leaves were dehydrated, covered with carbon and submitted to X-ray microanalysis. The C. gloeosporioides causer of the blister spot colonizes the coffee branch from the petiole to the insertion of the plagiotropic branch with the orthotropic branch. The best inoculation method on leaves was that which used the lesion from steel sponge. The best suspension concentration was of 4x10 6 conidia/mL. The best inoculation method on stem was that of insertion of a stick colonized by the fungus. Using the proposed scale, the evaluators presented better accuracy, precision, reproducibility and repeatability levels. Regarding the chemical constitution, a higher K content was found in the asymptomatic tissue surrounding the lesion, decreasing towards the symptomatic tissue.
The objectives of this work were to: verify the location of the pathogenic C. gloeosporioides on the stem; verify the best methodology for C. gloeosporioides inoculation on leaf and branch; construct and validate a diagrammatic scale to evaluate the severity of the blister spot on coffee leaves; and verify which mineral nutrients and their levels are present on the blister spot. The isolates were obtained from the leaves, petiole and plagiotropic branch, which was fragmented into 10 pieces. After isolation, the percentage of Colletotrichum spp. isolates was verified. To evaluate the best inoculation method in seedling leaves, the same were inoculated with five concentrations and six treatments. To evaluate the best inoculation method in the stem, the terminal internode was inoculated with six treatments. To construct and validate the scale, leaves were collected, and seven evaluators determined the real severity, defined the limits and constructed and validated the scale. To evaluate the chemical constitution of the lesions of coffee leaves containing symptomatic and asymptomatic tissue, the leaves were dehydrated, covered with carbon and submitted to X-ray microanalysis. The C. gloeosporioides causer of the blister spot colonizes the coffee branch from the petiole to the insertion of the plagiotropic branch with the orthotropic branch. The best inoculation method on leaves was that which used the lesion from steel sponge. The best suspension concentration was of 4x10 6 conidia/mL. The best inoculation method on stem was that of insertion of a stick colonized by the fungus. Using the proposed scale, the evaluators presented better accuracy, precision, reproducibility and repeatability levels. Regarding the chemical constitution, a higher K content was found in the asymptomatic tissue surrounding the lesion, decreasing towards the symptomatic tissue.
Descrição
Dissertação de Mestrado defendida na Universidade Federal de Lavras
Palavras-chave
Colletotrichum gloeosporioides, Composição química, Localização, Metodologia, Severidade
Citação
FREITAS, M. L. O. Etiologia, inoculação e escala diagramática no patossistema Colletrichum spp. x cafeeiro. 2014. ?121 f. Dissertação (Mestrado em Agronomia/Fitopatologia) - Universidade Federal de Lavras, Lavras. 2014.