Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Passalora gochnatiicola sp. nov. on Gochnatia amplexifolia from Serra do Cipó, MG, Brazil(Acta Botanica Brasilica, 2006-01) Pereira, Olinto Liparini; Barreto, Robert Weingart; Braun, UweThe leaf-spotting hyphomycete Passalora gochnatiicola sp. nov., collected on Gochnatia amplexifolia (Gardner) Cabrera (Asteraceae: Mutisieae) in the 'campos rupestres' of Serra do Cipó (Minas Gerais State, Brazil), is described, illustrated, discussed and compared with allied species.Item Reavaliação taxonômica de Colletotrichum guaranicola Albuq. agente causal da antracnose do guaranazeiro(Acta Amazonica, 2004) Bentes, Jânia Lília da Silva; Barreto, Robert WeingartFoi realizada uma reavaliação morfológica de estruturas reprodutivas e de infecção do agente causal da antracnose do guaranazeiro (Paullinia cupana var. sorbilis), visando confirmar a identidade do patógeno. Os resultados reforçam o reconhecimento da espécie Colletotrichum guaranicola Albuq., como um novo taxon dentro do gênero Colletotrichum.Item Sphaceloma poinsettiae as a potential biological control agent for wild poinsettia (Euphorbia heterophylla)(Biological Control, 2004-07) Nechet, Kátia de Lima; Barreto, Robert Weingart; Mizubuti, Eduardo S. G.Sphaceloma poinsettiae, a scab-causing fungus that attacks wild poinsettia (Euphorbia heterophylla) was evaluated as a mycoherbicide. Plants representing nine different E. heterophylla accessions were tested and variable resistance levels to 10 different isolates of S. poinsettiae were observed. One isolate was selected based on its high aggressiveness; it caused scab that led to stem-girdling in the majority of plants belonging to most wild poinsettia accessions. Plants inoculated with conidial suspension developed low disease severity; suspensions of mycelial fragments caused higher disease severity. Viability of mycelium declined rapidly either in storage under room temperature or at 4 °C. After 25 days, 60% of mycelial fragments kept in distilled water at 4 °C or in 35% sterile sucrose solution germinated. Cultures of S. poinsettiae were capable of growing at temperatures ranging from 10 to 30 °C (maximum growth at 25 °C) whereas the mycelial fragments germinated at 20–30 °C. The highest mycelial yield occurred in potato-dextrose broth after culturing for 12 days at 168 rpm at room temperature. A host-range test involving 37 plant species in addition to wild poinsettia indicated that S. poinsettiae is highly specific to E. heterophylla. The viability of S. poinsettiae as a mycoherbicide depends on the development of suitable mass production, formulation, and inoculum preservation methods. On several occasions, this fungus has been observed to cause devastating epidemics in the field on this host; therefore, it should be considered a potential biocontrol agent of wild poinsettia.Item Nimbya alternantherae a potential biocontrol agent for alligatorweed, Alternanthera philoxeroides(BioControl, 2007-04) Pomella, Alan William Vilela; Barreto, Robert Weingart; Charudattan, RaghavanAlligatorweed, (Alternanthera philoxeroides (Mart.) Griseb.), an aquatic and wetland plant native to South America, is an aggressive weed in many parts of the world. Its ability to compete with other native plants and to impede waterways has made it a serious threat to aquatic ecosystems. Although biological control with insects has been fairly successful in aquatic habitats, there is a need for additional agents to manage the weed in upland sites. Accordingly, in a survey in Brazil in 1997 a fungus, Nimbya (=Alternaria) alternantherae (Holcomb and Antonopoulus) Simmons and Alcorn, was discovered and confirmed to be highly damaging to alligatorweed. Studies were conducted to determine the potential of this fungus for controlling this weed. Several isolates from Brazil, USA, and Puerto Rico were compared and no differences in virulence were observed, although a lower dew requirement was demonstrated for the Brazilian isolates. Conidia were more effective than mycelial suspension, and inoculum concentrations of 1×105 and 1×106 conidia per ml provided significant levels of control of the weed in greenhouse and field experiments, respectively. In a host-range study, N. alternantherae infected 6 plant species from a total of 42 species belonging to 23 families. N. alternantherae has the potential to be an effective mycoherbicide for alligatorweed.Item First record of Glomerella cingulata causing leaf blight on Talauma ovata (Magnoliaceae)(Revista Árvore, 2005-08-10) Vieira, Bruno Sérgio; Pereira, Olinto Liparini; Batista, Márcio Luiz; Barreto, Robert WeingartGlomerella cingulata was found causing severe leaf blight on Talauma ovata, a common tree species in the Atlantic tropical rain forest floodplains of Southern Brazil. The disease and pathogen are described and illustrated and patogenicity is also demonstrated. This is the first report of this disease.Item Sintomatologia da murcha de Ceratocystis fimbriata em eucalipto(Revista Árvore, 2005-11-10) Ferreira, Francisco Alves; Maffia, Luiz Antônio; Barreto, Robert Weingart; Demuner, Nerino Luiz; Pigatto, SilvanaDescreveram-se o histórico da murcha de Ceratocystis fimbriata em eucalipto no Brasil e em outros países e a sintomatologia da doença, em plantações clonais com 4 meses a 5 anos de idade, em brotações de tocos, em estacas em enraizamento e em mudas clonais em viveiro, de quatro estados brasileiros. O patógeno evoluía-se da extremidade da raiz, atingindo o colo e tronco acima via parênquima medular, de onde, em diversas alturas, surgiam estrias escuras, que progrediam, via parênquima radial, matando uma porção de câmbio vascular, de floema e de feloderme. Dessa progressão sistêmica do patógeno, ascendente e radialmente, resultava uma lesão longitudinal externamente no tronco, contínua ou descontínua, marrom-avermelhada, coriácea, que passava a sulcada e, posteriormente, a cancro longitudinal, com seus calos longilíneos nas duas laterais. Por esse contexto sintomatológico, pode-se considerar essa enfermidade como um modelo de doença sistêmica em essência florestal, pelo menos na subárea da patologia florestal brasileira. Em brotações novas, em estacas em enraizamento e em mudas clonais as lesões eram longitudinais, contínuas ou descontínuas, negras a arroxeadas. A inativação de xilema em raízes, colo e em diferentes alturas do tronco, ou galho, dava-se pelo adensamento das estrias radiais escuras no lenho.Item First record of Botryosphaeria ribis associated with leaf spots on Magnolia aff. candollei in Brazil(Brazilian Journal of Microbiology, 2008-04-25) Macedo, Davi Mesquita de; Barreto, Robert WeingartA leaf spot disease was observed attacking some Magnolia aff. candollei plants grown in a private garden in the city of Rio de Janeiro, RJ, Brazil. Such leaf spots coalesced and led to extensive blight of foliage. A fungus was clearly associated to the disease symptoms and was identified as Botryosphaeria ribis. Its anamorph, Fusicoccum ribis, was also present, although less abundant than the teleomorph. This is first report of this fungus on this host in Brazil and the first record of any fungal disease on a member of the genus Magnolia in Brazil.