Coffee Science - v.11, n.4, 2016

URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/7836

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Assunto: search.filters.subject.Pragas, doenças e plantas daninhas

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    Colletotrichum on coffee trees in south of Minas Gerais - Brazil: physiological, molecular and pathogenic description
    (Editora UFLA, 2016-10) Armesto, Cecilia; Maia, Fernanda Gonçalves Martins; Monteiro, Fernando Pereira; Abreu, Mário Sobral de
    Fungi of the genus Colletotrichum spp. are cosmopolitan and are responsible for disease in many plants of agronomic importance. In coffee crops, three species have been described: Colletotrichum acutatum, Colletotrichum kahawae and Colletotrichum gloeosporioides. In Brazil were only reported the species C. acutatum and C. gloeosporioides, which symptoms are attributed as antracnoses, dieback and blister spot. This study evaluates the population of Colletotrichum spp. through morpho-physiological, genetic and pathogenic characteristics, in several coffee plantations in the southern of Minas Gerais. All isolates showed similar morphological and physiological characteristics, being identified as C. gloeosporioides. The best medium for mycelial growth was agar-malt extract with pH 5.5 and for spore production oat-agar medium with pH 6.5. When inoculated on berries, all isolates were pathogenic with variable levels of aggressiveness, but only 57% of these were pathogenic for hypocotyls. Three isolates, I-9, I-24 and I-26, were identified featuring the highest rates of aggressiveness in berries and hypocotyls.
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    Biological control of Hemileia vastatrix Berk. & Broome with Bacillus subtilis Cohn and biochemical changes in the coffee
    (Editora UFLA, 2016-10) Cacefo, Viviane; Araújo, Fábio Fernando de; Pacheco, Ana Cláudia
    Hemileia vastatrix stands out as one of the main phytosanitary problems of the coffee culture. The objective of this study was to evaluate the efficiency of the biological control of Hemileia vastatrix and detect some biochemical changes in plants of cultivars Icatu and Mundo Novo treated with foliar spray of Bacillus subtilis and azoxystrobin under field conditions. After the applications, leaves were collected for visual assessment of H. vastatrix severity in accordance with diagrammatic scales. For the biochemical evaluations related to plants defense, leaf tissue samples were collected for the analysis of proline, total phenols, total protein and lipid peroxidation. B. subtilis acted effectively in control of H. vastatrix in both cultivars, but with less efficiency than the azoxystrobin. Plants treated with B. subtilis presented greater proline, total phenols and total proteins in their leaves on the application of azoxystrobin. The cultivar Mundo Novo was more responsive to treatments that Icatu.