Fitopatologia - Artigos
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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 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 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 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.Item Additions to the mycobiota of the weed Lantana camara (Verbenaceae) in southeastern Brazil(Mycopathologia, 2001-05-17) Pereira, José Maurício; Barreto, Robert W.A sequel to the work of systematic surveying the mycobiota of Lantana camara aimed at finding potential biocontrol agents, was carried out during 1995–1996 covering part of its centre of origin in Brazil (state of Minas Gerais). Fifty-eight sampling sites, representing the four main climatic types in the state of Minas Gerais, were surveyed. Additional ad hoc collections were made in the states of Bahia, Espírito Santo, Paraná Rio de Janeiro and São Paulo. Fifteen fungal species were recorded in association with L. camara including the previously undescribed species Phomopsis lantanae-glutinosae sp. nov. Five fungi are also newly recorded on this host in Brazil: Cercospora lantanicola Corynespora cassiicola Meliola ambigua Mycovellosiella lantaniphila and Phomopsis lantanae. The following fungi, previously recorded on L. camara in Brazil, are recorded here for the first time in Minas Gerais: Dendryphielia aspera Micropustulomyces mucilaginosus Mycovellosiella lantanae Pseudocercospora guianensis and Puccinia lantanae.Item Streptopodium caricae sp. nov., with a discussion of powdery mildews on papaya, and emended descriptions of the genus Streptopodium and Oidium caricae(Mycological Research, 2004-07-04) Liberato, José R.; Barreto, Robert W.; Louro, Ricardo P.A new powdery mildew infecting papaya (Carica papaya) in Brazil, Streptopodium caricae sp. nov., is described. The species is compared with other anamorphic Erysiphales known to infect papaya: Oidiopsis sicula, Ovulariopsis papayae, Oidium caricae, O. papayae, O. caricicola, O. indicum, O. caricae-papayae, Podosphaera (syn. Sphaerotheca) spp., and Erysiphe spp. An emended description Streptopodium and a key to the anamorphs of powdery mildews on papaya are also presented. A re-examination of the type material of Phyllactinia caricaefolia showed that conidia in this material are dimorphic, indicating that its anamorph does not belong to Ovulariopsis and that the teleomorph is not conspecific with Phyllactinia guttata. Oidium caricae, the common powdery mildew of papaya, was re-examined, recognized as a member of subgenus Pseudoidium, an emended description was prepared, and a new type was indicated. O. papayae was recognized as a synonym of O. caricae, and many of the records of this fungus are considered to be doubtful or incorrect, either omitting a description of the fungus or including a description or illustration of an euodium conidiophore morphology.Item Queirozia turbinata (Phyllactinieae, Erysiphaceae): a powdery mildew with a dematiaceous anamorph(Mycological Research, 2006-04-17) 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.