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 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.