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1.
Edival Ângelo Valverde Zauza Lúcio Mauro da Silva Guimarães Nilza de Lima Pereira Sales Samuel Alves dos Santos Rafael Ferreira Alfenas Acelino Couto Alfenas 《Forest Pathology》2023,53(2):e12806
An outbreak of a new and severe disease was observed in Eucalyptus plantations of Bahia state, Brazil. An Ascomycota fungus has been frequently associated with the main symptoms of the disease namely leaf spot, branch cankers, shoot blight, defoliation, and dieback. Based on morphological characteristics, phylogenetic analysis (ITS and TEF-1α genes), and pathogenicity test on Eucalyptus plants, Pseudoplagiostoma eucalypti was identified as the causal agent of the disease. Although P. eucalytpi has been known from in Brazil since 1998, this is the first report of it causing severe disease and die-back on Eucalyptus spp. and we also record new symptoms associated with the pathogen. 相似文献
2.
Joseli da Silva Tatagiba Luiz Antonio Maffia Roberto W. Barreto Acelino C. Alfenas John C. Sutton 《Phytoparasitica》1998,26(1):8-19
Microbial isolates from living petals, petal residues and leaf residues of rose, and from laboratory collections, were evaluated
for control ofBotrytis cinerea in rose. In leaf residues artificially infested withB. cinerea, isolates of the filamentous fungiGliocladium roseum, FR136 (unidentified) andTrichoderma inhamatum reduced sporulation of the pathogen by >90%, other filamentous fungi were 25–90% effective, and those of yeasts and bacteria
were <50% effective. In artificially inoculated petal residues, no microbe reduced sporulation ofB. cinerea by >75%, but isolates ofCladosporium oxysporum and four yeasts were 51–75% effective, and three filamentous fungi, eight yeasts andBacillus subtilis isolates were 26–50% effective. Isolates ofT. inhamatum, C. oxysporum andG. roseum performed best againstB. cinerea among isolates evaluated in leaf residues naturally infested with the pathogen and indigenous microorganisms. Totals of ten
isolates of filamentous fungi (includingC. oxysporum andC. cladosporioides), two of yeasts and five ofBacillus subtilis completely prevented lesion production byB. cinerea in detached petals, and a further six isolates of filamentous fungi (includingG. roseum) and six yeasts were 90–99% effective. Isolates ofC. oxysporum, C. cladosporioides andB. subtilis, the most effective microorganisms againstB. cinerea in flower buds, reduced number of lesions in the range of 42–65% compared with 59–89% for à standard fungicide (vinclozolin).
It is suggested that application of leading antagonists Jo living rose leaves and flowers should optimize control of inoculum
production byB. cinerea when the tissues die. Optimal biocontrol of lesion production in flower buds requires a better understanding of the microenvironment
of petals. 相似文献
3.
Marcelo Luiz Laia Acelino Couto Alfenas Sergio Hermnio Brommonschenkel Shinitiro Oda Eduardo Jose de Melo Inae Marie de Arau jo Silva Janana Fernandes Goncalves Ariadne Marques 《林业研究》2015,(3)
Disease-resistant genes play an important role in defending against a variety of pathogens and insect pests in plants. Most of the disease-resistant genes encode pro-teins with conserved leucine rich r... 相似文献
4.
W. Quaedvlieg G.J.M. Verkley H.-D. Shin R.W. Barreto A.C. Alfenas W.J. Swart J.Z. Groenewald P.W. Crous 《Studies in Mycology》2013,75(1):307-390
Septoria represents a genus of plant pathogenic fungi with a wide geographic distribution, commonly associated with leaf spots and stem cankers of a broad range of plant hosts. A major aim of this study was to resolve the phylogenetic generic limits of Septoria, Stagonospora, and other related genera such as Sphaerulina, Phaeosphaeria and Phaeoseptoria using sequences of the the partial 28S nuclear ribosomal RNA and RPB2 genes of a large set of isolates. Based on these results Septoria is shown to be a distinct genus in the Mycosphaerellaceae, which has mycosphaerella-like sexual morphs. Several septoria-like species are now accommodated in Sphaerulina, a genus previously linked to this complex. Phaeosphaeria (based on P. oryzae) is shown to be congeneric with Phaeoseptoria (based on P. papayae), which is reduced to synonymy under the former. Depazea nodorum (causal agent of nodorum blotch of cereals) and Septoria avenae (causal agent of avenae blotch of barley and rye) are placed in a new genus, Parastagonospora, which is shown to be distinct from Stagonospora (based on S. paludosa) and Phaeosphaeria. Partial nucleotide sequence data for five gene loci, ITS, LSU, EF-1α, RPB2 and Btub were generated for all of these isolates. A total of 47 clades or genera were resolved, leading to the introduction of 14 new genera, 36 new species, and 19 new combinations.
Taxonomic novelties:
New genera - Acicuseptoria Quaedvlieg, Verkley & Crous, Cylindroseptoria Quaedvlieg, Verkley & Crous, Kirstenboschia Quaedvlieg, Verkley & Crous, Neoseptoria Quaedvlieg, Verkley & Crous, Neostagonospora Quaedvlieg, Verkley & Crous, Parastagonospora Quaedvlieg, Verkley & Crous, Polyphialoseptoria Quaedvlieg, R.W. Barreto, Verkley & Crous, Ruptoseptoria Quaedvlieg, Verkley & Crous, Septorioides Quaedvlieg, Verkley & Crous, Setoseptoria Quaedvlieg, Verkley & Crous, Stromatoseptoria Quaedvlieg, Verkley & Crous, Vrystaatia Quaedvlieg, W.J. Swart, Verkley & Crous, Xenobotryosphaeria Quaedvlieg, Verkley & Crous, Xenoseptoria Quaedvlieg, H.D. Shin, Verkley & Crous. New species - Acicuseptoria rumicis Quaedvlieg, Verkley & Crous, Caryophylloseptoria pseudolychnidis Quaedvlieg, H.D. Shin, Verkley & Crous, Coniothyrium sidae Quaedvlieg, Verkley, R.W. Barreto & Crous, Corynespora leucadendri Quaedvlieg, Verkley & Crous, Cylindroseptoria ceratoniae Quaedvlieg, Verkley & Crous, Cylindroseptoria pistaciae Quaedvlieg, Verkley & Crous, Kirstenboschia diospyri Quaedvlieg, Verkley & Crous, Neoseptoria caricis Quaedvlieg, Verkley & Crous, Neostagonospora caricis Quaedvlieg, Verkley & Crous, Neostagonospora elegiae Quaedvlieg, Verkley & Crous, Paraphoma dioscoreae Quaedvlieg, H.D. Shin, Verkley & Crous, Parastagonospora caricis Quaedvlieg, Verkley & Crous, Parastagonospora poae Quaedvlieg, Verkley & Crous, Phlyctema vincetoxici Quaedvlieg, Verkley & Crous, Polyphialoseptoria tabebuiae-serratifoliae Quaedvlieg, Alfenas & Crous, Polyphialoseptoria terminaliae Quaedvlieg, R.W. Barreto, Verkley & Crous, Pseudoseptoria collariana Quaedvlieg, Verkley & Crous, Pseudoseptoria obscura Quaedvlieg, Verkley & Crous, Sclerostagonospora phragmiticola Quaedvlieg, Verkley & Crous, Septoria cretae Quaedvlieg, Verkley & Crous, Septoria glycinicola Quaedvlieg, H.D. Shin, Verkley & Crous, Septoria oenanthicola Quaedvlieg, H.D. Shin, Verkley & Crous, Septoria pseudonapelli Quaedvlieg, H.D. Shin, Verkley & Crous, Setophoma chromolaenae Quaedvlieg, Verkley, R.W. Barreto & Crous, Setoseptoria phragmitis Quaedvlieg, Verkley & Crous, Sphaerulina amelanchier Quaedvlieg, Verkley & Crous, Sphaerulina pseudovirgaureae Quaedvlieg, Verkley & Crous, Sphaerulina viciae Quaedvlieg, H.D. Shin, Verkley & Crous, Stagonospora duoseptata Quaedvlieg, Verkley & Crous, Stagonospora perfecta Quaedvlieg, Verkley & Crous, Stagonospora pseudocaricis Quaedvlieg, Verkley, Gardiennet & Crous, Stagonospora pseudovitensis Quaedvlieg, Verkley & Crous, Stagonospora uniseptata Quaedvlieg, Verkley & Crous, Vrystaatia aloeicola Quaedvlieg, Verkley, W.J. Swart & Crous, Xenobotryosphaeria calamagrostidis Quaedvlieg, Verkley & Crous, Xenoseptoria neosaccardoi Quaedvlieg, H.D. Shin, Verkley & Crous. New combinations - Parastagonospora avenae (A.B. Frank) Quaedvlieg, Verkley & Crous, Parastagonospora nodorum (Berk.) Quaedvlieg, Verkley & Crous, Phaeosphaeria papayae (Speg.) Quaedvlieg, Verkley & Crous, Pseudocercospora domingensis (Petr. & Cif.) Quaedvlieg, Verkley & Crous, Ruptoseptoria unedonis (Roberge ex Desm.) Quaedvlieg, Verkley & Crous, Septorioides pini-thunbergii (S. Kaneko) Quaedvlieg, Verkley & Crous, Sphaerulina abeliceae (Hiray.) Quaedvlieg, Verkley & Crous, Sphaerulina azaleae (Voglino) Quaedvlieg, Verkley & Crous, Sphaerulina berberidis (Niessl) Quaedvlieg, Verkley & Crous, Sphaerulina betulae (Pass.) Quaedvlieg, Verkley & Crous, Sphaerulina cercidis (Fr.) Quaedvlieg, Verkley & Crous, Sphaerulina menispermi (Thüm.) Quaedvlieg, Verkley & Crous, Sphaerulina musiva (Peck) Quaedvlieg, Verkley & Crous, Sphaerulina oxyacanthae (Kunze & J.C. Schmidt) Quaedvlieg, Verkley & Crous, Sphaerulina patriniae (Miura) Quaedvlieg, Verkley & Crous, Sphaerulina populicola (Peck) Quaedvlieg, Verkley & Crous, Sphaerulina quercicola (Desm.) Quaedvlieg, Verkley & Crous, Sphaerulina rhabdoclinis (Butin) Quaedvlieg, Verkley & Crous, Stromatoseptoria castaneicola (Desm.) Quaedvlieg, Verkley & Crous. Typifications: Epitypifications - Phaeosphaeria oryzae I. Miyake, Phaeoseptoria papayae Speg.; Neotypification - Hendersonia paludosa Sacc. & Speg.Key words: Capnodiales, Multi-Locus Sequence Typing (MLST), Mycosphaerella, Mycosphaerellaceae, Phaeoseptoria, Phaeosphaeria, Phaeosphaeriaceae, Pleosporales, Septoria, Sphaerulina, Stagonospora, systematics 相似文献5.
Nilmara P. Caires Pollyane S. Hermenegildo Lúcio M. S. Guimares Reginaldo G. Mafia Edival . V. Zauza Norton Borges Júnior Jorge L. Badel Acelino C. Alfenas 《Forest Pathology》2019,49(4)
Dieback caused by Erwinia psidii is currently one of the most important emerging diseases in eucalypt plantations in Brazil. However, little is known in terms of the host range of this pathogen or the potential sources of resistance against the disease it causes. In this study, we inoculated plants of species from nine families to gain insight into the host range of E. psidii. Plants of all inoculated species of Myrtaceae except Acca sellowiana exhibited disease symptoms and therefore represent potential hosts for the pathogen under natural conditions. In addition, the response of four Corymbia species, 29 Eucalyptus species and three interspecific Eucalyptus hybrids to inoculation with E. psidii was evaluated. All Corymbia henryi, Corymbia maculata, Eucalyptus thozetiana, Eucalyptus cloeziana, Eucalyptus viminalis, Eucalyptus dalrympleana and Eucalyptus pilularis plants were highly resistant to the pathogen, whereas differential disease resistance was observed in the other species. This study provides important information on sources of resistance to Erwinia psidii with potential use in the development of clones with enhanced resistance in eucalypt species of economic importance. 相似文献
6.
R. G. Freitas R. F. Alfenas L. M. S. Guimarães J. L. Badel A. C. Alfenas 《Plant pathology》2019,68(5):869-877
Calonectria leaf blight, caused by Calonectria pteridis, is currently one of the main foliar diseases in eucalypt plantations in Brazil. In warm and high rainfall regions, the disease can be a limiting factor for eucalypt production when planting susceptible genotypes. The most effective method for controlling this disease in the field is the use of resistant genotypes, which requires knowledge of the genetic variability and aggressiveness of the pathogen population for effective deployment of plant resistance. This work evaluated the genetic diversity and aggressiveness of C. pteridis populations obtained from infected eucalypt plants in Monte Dourado (Pará state) and Imperatriz (Maranhão state), Brazil. To study the genetic diversity, 16 ISSR primers were tested, five of which amplified polymorphic, reproducible and informative bands. Thirty-one closely related genotypes were identified from 84 isolates studied, indicating that the population has a low genetic diversity. The aggressiveness of seven isolates, selected according to geographic origin and their clustering in the ISSR-based dendogram, was determined by inoculation of a hybrid Eucalyptus grandis × E. urophylla clone under controlled conditions. Disease severity was assessed by both measuring the percentage of plant defoliation and assigning a score according to a diagrammatic scale of symptoms. A high correlation between the two evaluation methods was observed, which revealed significant differences in aggressiveness among the isolates. The diagrammatic scale is recommended for disease evaluation because results are obtained much faster, before the occurrence of severe defoliation. No correlation between clustering in the ISSR-based phylogenetic analysis and aggressiveness was observed. 相似文献
7.
H. G. M. Ferraz G. A. Demuner L. M. S. Guimarães D. A. A. Arriel A. C. da Silva N. B. Junior R. G. Mafia A. C. Alfenas 《Forest Pathology》2016,46(3):240-247
The dieback and wilting caused by Erwinia psidii are emerging eucalypt diseases that have been observed since 2014 in the south and central‐south regions of Brazil. Field observations have shown variability in disease severity resistance among Eucalyptus spp. clones and species. It is hypothesized that this variability is due to genetic resistance. To confirm this hypothesis, inoculations in genetically distinct eucalypt plants are necessary. However, lack of an inoculation method and disease assessment makes difficult to select resistant genotypes for use in commercial plantations or genetic breeding programmes. Three inoculation methods were tested on eight clones of Eucalyptus spp. Among them, inoculum deposition with bacteria‐impregnated toothpick on the axillary buds was the simplest and most effective, capable to reproduce the disease symptoms observed under conditions of natural infection. We also developed a rating scale for disease assessment. Among eight clones tested, only Clone 1 (Eucalyptus saligna) and Clone 2 (Eucalyptus urophylla) were resistant. 相似文献
8.
Powdery mildew symptoms and signs were observed on seedlings of Lagerstroemia speciosa within an ornamental plant nursery in Viçosa, State of Minas Gerais, Brazil. Signs were most prominent as intense mycelial growth and sporulation on the shoots, new branches and leaves, which led to tissue necrosis. Based on morphological characteristics and phylogenetic analyses of ITS and 28S rDNA sequences, the powdery mildew pathogen of L. speciosa was identified as Erysiphe australiana, a well‐known powdery mildew pathogen infecting Lagerstroemia spp. worldwide. To our knowledge, this is the first report of E. australiana causing powdery mildew on L. speciosa in Brazil. 相似文献
9.
Genetic diversity of the myrtle rust pathogen (Austropuccinia psidii) in the Americas and Hawaii: Global implications for invasive threat assessments 
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下载免费PDF全文 J. E. Stewart A. L. Ross‐Davis R. N. Graҫa A. C. Alfenas T. L. Peever J. W. Hanna J. Y. Uchida R. D. Hauff C. Y. Kadooka M.‐S. Kim P. G. Cannon S. Namba S. Simeto C. A. Pérez M. B. Rayamajhi D. J. Lodge M. Arguedas R. Medel‐Ortiz M. A. López‐Ramirez P. Tennant M. Glen P. S. Machado A. R. McTaggart A. J. Carnegie N. B. Klopfenstein 《Forest Pathology》2018,48(1)
Since the myrtle rust pathogen (Austropuccinia psidii) was first reported (as Puccinia psidii) in Brazil on guava (Psidium guajava) in 1884, it has been found infecting diverse myrtaceous species. Because A. psidii has recently spread rapidly worldwide with an extensive host range, genetic and genotypic diversities were evaluated within and among A. psidii populations in its putative native range and other areas of myrtle rust emergence in the Americas and Hawaii. Microsatellite markers revealed several unique multilocus genotypes (MLGs), which grouped isolates into nine distinct genetic clusters [C1–C9 comprising C1: from diverse hosts from Costa Rica, Jamaica, Mexico, Puerto Rico, and USA‐Hawaii, and USA‐California; C2: from eucalypts (Eucalyptus spp.) in Brazil/Uruguay and rose apple (Syzygium jambos) in Brazil; C3: from eucalypts in Brazil; C4: from diverse hosts in USA‐Florida; C5: from Java plum (Syzygium cumini) in Brazil; C6: from guava and Brazilian guava (Psidium guineense) in Brazil; C7: from pitanga (Eugenia uniflora) in Brazil; C8: from allspice (Pimenta dioica) in Jamaica and sweet flower (Myrrhinium atropurpureum) in Uruguay; C9: from jabuticaba (Myrciaria cauliflora) in Brazil]. The C1 cluster, which included a single MLG infecting diverse host in many geographic regions, and the closely related C4 cluster are considered as a “Pandemic biotype,” associated with myrtle rust emergence in Central America, the Caribbean, USA‐Florida, USA‐Hawaii, Australia, China‐Hainan, New Caledonia, Indonesia and Colombia. Based on 19 bioclimatic variables and documented occurrences of A. psidii contrasted with reduced sets of specific genetic clusters (subnetworks, considered as biotypes), maximum entropy bioclimatic modelling was used to predict geographic locations with suitable climate for A. psidii which are at risk from invasion. The genetic diversity of A. psidii throughout the Americas and Hawaii demonstrates the importance of recognizing biotypes when assessing the invasive threats posed by A. psidii around the globe. 相似文献
10.
Severity of Xanthomonas axonopodis leaf blight on eucalypt cuttings under different levels of nutrients 下载免费PDF全文
下载免费PDF全文 Bacterial leaf blight of eucalypt, caused by Xanthomonas axonopodis, occurs mainly in forest nurseries, but also affects young plants in the field. Avoidance of leaf wetness for long periods of time over the whole nursery and using drip irrigation for clonal hedges are, currently, the most effective measures for controlling bacterial leaf blight on eucalypt. However, as these techniques are very costly, alternative management measures are required. We hypothesized that the management of mineral nutrients could reduce disease severity on eucalypts. To examine this hypothesis, rooted cuttings of Eucalyptus urophylla × E. grandis were irrigated with nutrient solutions containing different concentrations of copper (Cu), boron (Bo), potassium (K), calcium (Ca) and nitrogen (N) before inoculation with X. axonopodis 30 days after starting the nutrient solution treatments. Concentration of K higher than that recommended, commonly used in miniclonal hedges, reduced the severity of bacterial leaf blight. However, disease severity increased with an increasing of N/K ratio. The management of mineral nutrition solution, especially K, has great potential for integrated disease management of X. axonopodis in eucalypt nurseries. 相似文献