Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Queirozia turbinata (Phyllactinieae, Erysiphaceae): a powdery mildew with a dematiaceous anamorph(Mycological Research, 2006-05) Liberato, José R.; Barreto, Robert W.; Niinomi, Seiko; Takamatsu, SusumuThe powdery mildew monotypic genus Queirozia was reduced to a synonym of Pleochaeta in 1982. Now, a re-examination of the type material of Queirozia and of two other specimens showed that Queirozia turbinata has a very distinct combination of characters that do not allow its placement within Pleochaeta. It has forked special aerial hyphae, subclavate and predominantly lemon-shaped conidia, and both conidiophores and conidia varying from greyish to yellowish brown (a feature that appears to be unique for this fungus within the Erysiphales). This may represent the first dematiaceous anamorphic powdery mildew known to science. This fungus also has hemiendophytic mycelium, a character considered almost exclusive to the tribe Phyllactinieae. The outer wall surface pattern of wrinkled and turgid conidia of Q. turbinata as observed under the SEM is different from those presented in the literature for this tribe. Molecular analysis showed that Q. turbinata belongs to the tribe Phyllactinieae and is phylogenetic closer to Pleochaeta than to Leveillula or Phyllactinia. It is therefore acknowledged that Queirozia is closely related to Pleocheta but too distinct morphologically from this genus to be accepted as a synonym. Emended descriptions of Queirozia and Q. turbinata are presented.Item Pseudocercospora lonicerigena a leaf spot fungus on the invasive weed Lonicera japonica in Brazil(Australasian Plant Pathology, 2014-05) Miranda, Bruno E. C. de; Ferreira, Bruno Wesley; Alves, Janaína L.; Macedo, Davi M. de; Barreto, Robert W.Lonicera japonica (Japanese honeysuckle), a plant of Asian origin introduced as an ornamental into many countries, has become an invasive weed in some exotic situations, such as in southern Brazil. Classical biological control (CBC) with natural enemies collected in the centre of origin is considered to be the best alternative for sustainable management of L. japonica. In the context of this strategy, previous knowledge of the natural enemies already present in the target area is of great importance in order to avoid un-necessary introductions of CBC agents from the weed’s native range. Recently, examination of populations of L. japonica in localities in the Brazilian states of Rio de Janeiro and Paraná revealed the presence of leaf spots consistently associated with a cercosporoid hyphomycete. A molecular and morphological study of this fungus led to its recognition as Pseudocercospora lonicerigena. There were few differences when the Brazilian isolate was compared with a strain found in North America. This is the first report of this fungus in Brazil. The fungus was isolated in pure culture and inoculation of healthy leaves of L. japonica eventually led to leaf yellowing and necrosis, indicating that P. lonicerigena is not highly pathogenic, as evidenced by the continuing advance of this weed in southern Brazil. Therefore, the introduction of additional co-evolved natural enemies collected in Asia, perhaps piggy-backing on an ongoing project already underway in New Zealand, will be necessary to control this invasive alien weed in Brazil.Item The mycobiota of the weed Lantana camara in Brazil, with particular reference to biological control(Mycological Research, 1995-07) Barreto, Robert W.; Evans, Harry C.; Ellison, Carol A.A survey of the fungi associated with the tropical weed Lantana camara was conducted during 1988 and 1989 in part of its native range in southern Brazil. The sampling activity was concentrated mainly in the state of Rio de Janeiro, covering 70 sites located in different climatic or ecological zones. The survey continued and was extended to the Amazon and northeast regions. Nine fungal species were identified as members of the mycobiota, including the previously undescribed fungi: Ceratobasidium lantanae-camarae sp. nov., Dendryphiella aspera sp. nov. and Micropustulomyces mucilaginosus gen. et sp. nov. Perisporiopsis lantanae, which has not been recorded previously in Brazil, has its anamorph described for the first time. The rusts Aecidium lantanae were also recorded. Field observations suggest that several fungal pathogens have potential as classical biocontrol agents of the weed in the Old World tropics: Ceratobasidium lantanae-camarae and Puccinia lantanae in lowland humid climates; Mycovellosiella lantanae, Prospodium tuberculatum and Micropustulomyces mucilaginosus in more elevated or subtropical areas. In addition, databases and herbaria were consulted in order to compile a world list of fungal pathogens associated with L. camara.Item Fungal pathogens of Calotropis procera (rubber bush), with two new records from Brazil(Australasian Plant Pathology, 1999-06) Barreto, Robert W.; Pomella, Alan W. V.; Evans, Harry C.Fungal pathogens associated with the asclepiadaceous weed Calotropis procera (rubber bush) are documented from published, as well as unpublished sources. Two new host-pathogen associations from Brazil; Phaeoramularia calotropidis and Puccinia obliqua, are recorded. The latter species infects the host systemically and induces the formation of conspicuous and damaging witches’ brooms. The rust appears to exert some control of C. procera in the more humid areas of Brazil and the biocontrol potential of this and the other listed pathogens is discussed.Item Production of viable and infective inoculum of Coccodiella miconiae (Ascomycota: Phyllachoraceae) for the biological control of Miconia calvescens(Biological Control, 2014-12) Alves, Janaina L.; Santos-Seixas, Claudine D.; Rodrigues, Fabrício A.; Barreto, Robert W.Miconia calvescens is a small tree from the Neotropics that has become an aggressive invader of forest ecosystems in the Pacific. Classical biological control is the sole sustainable method for controlling such invasions. Among the numerous pathogens that have been found on miconia, the fungus Coccodiela miconiae stands out as a very promising biocontrol agent. It is often found in native situations causing a severe disease (yellow pustule) despite being commonly intensively attacked by a series of mycoparasites. However, the fungus is not easily manipulated and is difficult to preserve under controlled conditions because it is a strict biotroph. Elucidation of details of the biology of C. miconiae is needed to allow for its use in biological control. Herein results of a broad range of tests that were performed are presented. Such tests aimed at determining: (1) an efficient method for obtaining viable and infective ascospores; (2) effect of temperature, light and other factors on ascospores; (3) a protocol for plant inoculation. It was concluded that ascospores are efficiently obtained when mature stromata are detached from leaves and agitated in water for 3–4 h and that such suspension is infective when used immediately. Ascospore germination was favored by incubation at 25 °C under a 12 h of light/12 h dark regime. A protocol for inoculation of C. miconiae is described. These findings indicate that it may now be possible to manipulate C. miconiae as a classical biocontrol agent.Item Phoma destructiva causing blight of tomato plants: a new fungal threat for tomato plantations in Brazil?(Tropical Plant Pathology, 2017-11-20) Colmán, Adans A.; Alves, Janaina L.; Silva, Meiriele da; Barreto, Robert W.Solanum lycopersicum is among the most important crops in Brazil. This crop is affected by a large range of fungal diseases that are recognized as major limitations for tomato production. Recently, plants grown in a greenhouse in Viçosa, Minas Gerais, Brazil, were found to bear severe blight symptoms. A pycnidial coelomycete was repeatedly found in association with necrotic tissues. The fungus had its morphology recognized as equivalent to that of Phoma and related genera. A phylogenetic analysis based on nrDNA (ITS) and partial β-tubulin (TUB) sequences led to the conclusion that the fungus involved was Phoma destructiva. Pathogenicity tests showed that, after 5 days, blight symptoms developed on leaves, flowers and stems of plants belonging to thirteen different tomato varieties tested. This fungal species is mostly known for causing post-harvest tomato rot, which is only regarded as a secondary disease in Brazil. This is in disagreement with the observations made in this work. Here, the disease symptoms caused by the fungus were very severe, fully justifying the scientific name of the pathogen. Under favorable environmental conditions, aggressive strains of P. destructiva, such as the one isolated in this study, may become significant threats to tomato plantations in Brazil.Item Nimbya alternantherae and Cercospora alternantherae: two new records of fungal pathogens on Alternanthera philoxeroides (alligatorweed) in Brazil(Australasian Plant Pathology, 1999-06) Barreto, Robert W.; Torres, André N. L.Alternanthera philoxeroides is an amphibious herbaceous weed (alligatorweed) of the Amaranthaceae, and is a native of South America. It has become a very aggressive invader in many regions of the world. A preliminary survey for fungal pathogens to be used as biocontrol agents for this weed of five Brazilian States yielded two species, Nimbya alternantherae and Cercospora alternantherae. This is the first report of these species from Brazil. The pathogenicity of these fungi was tested against plants from Brazilian and Australian biotypes of A. philoxevoides. N. alternantherae was shown to be very damaging and appears to have biocontrol potential.Item The Colletotrichum orbiculare species complex: Important pathogens of field crops and weeds(Fungal Diversity, 2013-06-27) Barreto, Robert W.; Guatimosim, Eduardo; Crous, Pedro W.; Liu, Fang; Cannon, Paul F.; Damm, UlrikeColletotrichum orbiculare causes anthracnose of Cucurbitaceae and is phylogenetically closely related to pathogens of several other herbaceous hosts belonging to the Asteraceae, Fabaceae and Malvaceae. Most of them are known for their hemibiotrophic infection strategy and as destructive pathogens either of field crops or weeds. In order to study the phylogenetic relationships of these fungi, a multilocus analysis (ITS, GAPDH, CHS-1, HIS3, ACT, TUB2, GS) of 42 strains of C. orbiculare and related species was conducted. The analysis resulted in nine clades that confirmed the four species previously known as belonging to this species complex, C. lindemuthianum, C. malvarum, C. orbiculare and C. trifolii, and recognised four new species from weeds, namely C. bidentis, C. sidae, C. spinosum and C. tebeestii. The name C. orbiculare itself is widely used in plant pathology and science, but is invalid according to current nomenclatural rules. Therefore we described a new species with the same epithet and a type specimen that agrees with our current understanding of this species, and is linked to a living culture. Following the recent epitypification of C. lindemuthianum, we chose appropriate specimens with associated strains to serve as epitypes of C. malvarum and C. trifolii, and selected an authentic specimen of C. trifolii as lectotype.Item Pyriculariopsis calatheae sp. nov., a novel anamorphic hyphomycete from the Atlantic forest of Brazil causing leaf spots on Calathea longifolia(Mycological Progress, 2011-09-14) Soares, Dartanhã J.; Rocha, Fabiano B.; Duarte, Lidiane L.; Barreto, Robert W.The new species Pyriculariopsis calatheae is described causing leaf spots on Calathea longifolia (Marantaceae). It represents an addition to the mycobiota of the tropical seasonal semi-deciduous montane forest, a component of the Brazilian Atlantic forest and a highly threatened ecosystem.Item Pseudocercospora cryptostegiae-madagascariensis sp. nov. on Cryptostegia madagascariensis, an Exotic Vine Involved in Major Biological Invasions in Northeast Brazil(Mycopathologia, 2008-04-18) Silva, Janaina L. da; Barreto, Robert W.; Pereira, Olinto L.Cryptostegia madagascariensis is a plant native from Madagascar, belonging to the Apocynaceae that is invading the native vegetation in Northeast Brazil and threatening the unique riverine formations dominated by the carnauba palm. Individuals of C. madagascariensis cultivated in the campus of the Universidade Federal de Viçosa, state of Minas Gerais, Brazil, showing leaf spot symptoms of unknown etiology were observed. Two fungal species were found associated to such leaf spots: Colletotrichum gloeosporioides and a new species of Pseudocercospora. The latter was named Pseudocercospora cryptostegiae-madagascariensis and described herein. The discovery of those two fungal pathogens on C. madagascariensis coincide with the recognition that the weedy vine that is involved in the infestations in the Northeast of Brazil is not Cryptostegia grandiflora as formerly reported. These mycological findings are of greater importance now since C. madagascariensis is likely to become a target for biological control together with its former status in Brazil of an ornamental plant of limited relevance.
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