Pleospora Herbarum Research Articles

Effect of Some Biological Agents on Fungi Isolated from Roots and Soil around it of Cupressus spp. Trees

Al-Ameri, H.A. 2024. Effect of Some Biological Agents on Fungi Isolated from Roots and Soil around it of Cupressus spp. Trees. Arab Journal of Plant Protection, 42(2): 224-228. https://doi.org/10.22268/AJPP-001233 Relative occurrence of fungi associated with six root and six soil samples from the rhizosphere of Cupressus/cypruss trees with root rot, leaf blight or wilt symptoms were investigated. Results of the root samples (average of six samples) showed that the relative occurrence of Fusarium culmorum was the highest (36.81%), followed by F. solani (29.7%), Alternaria. alternate (14.19%), F. oxysporum (10.67%), R. solani (5.51%), Pythium spp. (1.69%), Helminthosporium spp. (0.85%), Bipolaris spp. (0.24%) and Stemphilium herbarum (0.18%). However, the average occurrence in the six soil rhizosphere samples was the highest for F. solani (41.28%), followed by R. solani (19.76%), F. culmorum (16.5%), F. oxysporum (8.77%), Bipolaris spp. (6.17%), A. alternata (3.99%), Pythium spp. (2.70%), Stemphylium herbarum (0.60%), and Helminthosporium spp. (0.27%). Results also showed that Trichoderma harzianum had a high antagonistic efficiency against the three studied fungi isolated from cypress tree roots and the surrounding soil, namely F. culmorum, F. solani and Helminthosporium spp. Based on 1-5 scale, the inhibition level was 1.0 against each of the pathogenic fungi F. culmorum, F. solani, and 2.0 against Helminthosporium spp. The results also showed that the use of B. subitlis as bacterial bio-control agent led to a significant inhibition of the growth of the three isolated fungi, F. culmorum, F. solani and Helminthosporium spp. cultured on PDA medium. Keywords: Bio-control agents, F. culmorum, F. solani, Cypress trees.

Fungal allergen sensitization: Prevalence, risk factors, and geographic variation in the United States

Many fungal species are associated with the pathogenesis of allergic disease, yet most epidemiologic studies on IgE-mediated fungal sensitization have only included a few species. We investigated fungal allergen sensitization prevalence, risk factors, and geographic variation in the United States. From 2014 to 2019, a total of 7,912,504 serum-specific IgE (sIgE) test results for 17 fungal species were measured in 1,651,203 patients aged 0-85 years by a US-wide clinical laboratory. Fungal sensitization prevalence, patterns, and relationship with demographic characteristics, clinical diagnoses, and geographic regions were analyzed. Twenty-two percent of patients were positive (sIgE>0.10 kUA/L) to at least 1 fungal allergen; 13.7% were positive to >2 fungal allergens. Fungal species-specific positivity rates ranged 7.4-18.6% and were highest for Candida albicans (18.6%), Alternaria alternata (16.6%), Stemphylium herbarum (14.9%), and Aspergillus fumigatus (14.2%). Other fungi that were frequently tested had relatively low positivity rates (eg,Cladosporium herbarum 11.1%, Penicillium chrysogenum 10.7%). Independent risk factors for test positivity for all fungal species included male sex, teen age (highest in those aged 10-19 years), atopic dermatitis, and asthma. Fungal sensitization was generally higher in urban areas and ecoregions composed predominantly of grasslands and prairies compared to woodlands and forest, although there was greater variation in sensitization risk to different fungi in different ecoregions. Independent risk factors for fungal sensitization include male sex, teen ages, atopic dermatitis, asthma, and ecoregion.

Screening and Identification of Garlic Leaf Blight (Pleospora herbarum)-Resistant Mutants Induced by Ethyl Methane Sulphonate.

Garlic (Allium sativum L.) is a popular condiment used as both medicine and food. Garlic production in China is severely affected by continuous cropping and is especially affected by leaf blight disease. Garlic is sterile, so it is very important to develop specialized genotypes, such as those for disease resistance, nutritional quality, and plant architecture, through genetic modification and innovation. In this experiment, we applied the induction method using EMS to mutate garlic cloves of cultivar G024. From the mutations, 5000 M0 mutants were generated and planted in the field. Then, 199 M1 mutant lines were screened according to growth potential and resistance to leaf blight. From M2 to M3, 169 generational lines were selected that grew well and were resistant to leaf blight in the field. Thereafter, their resistance to leaf blight was further analyzed in the lab; 21 lines resistant to leaf blight that had good growth potential were identified, among which 3 mutants were significantly different, and these were further screened. Also, transcriptome analysis of two mutants infected with Pleospora herbarum, A150 and G024, was performed, and the results revealed 2026 and 4678 differentially expressed genes (DEGs), respectively. These DEGs were highly enriched in hormone signaling pathway, plant-pathogen interaction, and MAPK signaling pathway. Therefore, the results provide a theoretical and technical basis for the creation of garlic germplasm resistant to leaf blight.

Onion stemphiliosis in the South of Ukraine

Onion stemphiliosis is a relatively new disease in Ukraine, so a deeper study of Stemphylium, the species composition of the pathocenosis, and isolation and determination of the species belonging of pathogens of the disease are relevant. The purpose of the study was to examine the species composition of pathocenosis, the biofenology of the causative agent of stemphiliosis, and determine the effectiveness of fungicides for further control of stemphiliosis in onion crops. The main research methods were: field – to determine the spread, development, and harmfulness of stemphiliosis; laboratory – to examine pathogens of onion diseases; visual and mathematical – statistical. The method of mycological crops on potato-dextrose agar (PDA) was used in the work. Field surveys in 2019-2021 established the spread and development of stemphiliosis in onion plantings in the Odesa District of the Odesa region. It was identified that the growing season of 2021 was the most favourable for stemphiliosis, when against the background of high humidity and air temperatures, the spread of the disease was 100%, and the development of the disease reached 79%. In onion crops, the disease developed unevenly, its spread was low in June, with rapid growth in July. At the beginning of August, the percentage of the disease reached 80%. Eight types of fungi were identified, of which Stemphylium vesicarium (Wallr.) Simm, Stemphylium botryosum Wallr, Stemphylium herbarum Simm. – are pathogens of onion stemphiliosis. Laboratory studies established the frequency of their distribution in samples. It is proved that five-time spraying with fungicides helps to reduce the further development of stemphiliosis in onion plantings. The high effectiveness of spraying plants with appropriate fungicides with the active substance fluopyram (200 g/l) + tebuconazole (200 g/l) and fluoxastrobin (100 g/l) + prothioconazole (100 g/l) to suppress the development of spores of pathogens is proven. The provisions and conclusions on the phytosanitary condition of onion plantations in the Odesa region are further developed. The results of the research can serve to develop recommendations for production on the implementation of measures to protect onions from stemphiliosis

Batı Karadeniz Bölgesi’nde fasulye tohumlarında bulunan fungal hastalıkların belirlenmesi

Bu çalışma Batı Karadeniz Bölgesi’nde Zonguldak, Bartın ve Karabük illerinde fasulye ekiliş alanlarından toplanan fasulye tohumlarında görülen fungal hastalık etmenlerinin belirlenmesi amacıyla 2012-2014 yılları arasında yürütülmüştür. Tohum örnekleri sürvey yapılan illerdeki seralardan toplanmıştır. Bu tohumlardan funguslar izole edildikten sonra, izolatlar hem morfolojik hem de moleküler olarak teşhis edilmiştir. Çalışma sonucunda tohum örneklerinden, Pseudocercospora griseola (%53), Stemphylium vesicarium (%14.5), Fusarium oxysporum (%6.5), Fusarium solani (%5.25), Stemphylium globuliferum (%4.5), Stemphylium herbarum (tel: Pleospora herbarum) (%2), Fusarium sambucinum (%1), Trichothecium roseum (%0.75) ve Paecilomyces sp. (%2.5) bitki patojeni fungal türler elde edilmiştir.

Гриби класу Dothideomycetes зелених насаджень населених пунктів степової зони України

Гриби класу Dothideomycetes зелених насаджень населених пунктів степової зони України

Alternaria infectoria and Stemphylium herbarum, two new pathogens of pyrethrum (Tanacetum cinerariifolium) in Australia

Perithecia at the base of dead flower stems of pyrethrum (Tanacetum cinerariifolium) plants in yield-decline affected fields of northern Tasmania were identified as Alternaria infectoria and Stemphylium herbarum. Identification was based on morphological description of cultures established from single ascospores; and conidiospores; ascospore shape and septation; and multigene phylogenetic analyses using the internal transcribed spacer (ITS) region, translation elongation factor 1-α (EF1), polymerase II second largest subunit (RPB2) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) genes. Stemphylium herbarum produced necrotic leaf lesions on both sides of the spray inoculated pyrethrum leaves which coalesced to encompass the entire leaf in in vivo and in vitro experiments. Alternaria infectoria produced small necrotic leaf lesions on both sides of the leaves two weeks after inoculation which did not expand and hence, was considered as a minor pathogen of pyrethrum. This is the first report of A. infectoria and S. herbarum as pathogens of pyrethrum in Australia. The role of A. infectoria and S. herbarum in pyrethrum yield-decline in northern Tasmania needs to be evaluated.

Stemphylium Leaf Blight of Garlic (Allium sativum ) in Spain: Taxonomy and In Vitro Fungicide Response.

The most serious aerial disease of garlic is leaf blight caused by Stemphylium spp. Geographical variation in the causal agent of this disease is indicated. Stemphylium vesicarium has been reported in Spain, whereas S. solani is the most prevalent species recorded in China. In this study, Stemphylium isolates were obtained from symptomatic garlic plants sampled from the main Spanish production areas. Sequence data for the ITS1–5.8S–ITS2 region enabled assignation of the isolates to the Pleospora herbarum complex and clearly distinguished the isolates from S. solani. Conidial morphology of the isolates corresponded to that of S. vesicarium and clearly discriminated them from S. alfalfae and S. herbarum on the basis of the size and septation pattern of mature conidia. Conidial morphology as well as conidial length, width and length:width ratio also allowed the Spanish isolates to be distinguished from S. botryosum and S. herbarum. Control of leaf blight of garlic is not well established. Few studies are available regarding the effectiveness of chemical treatments to reduce Stemphylium spp. incidence on garlic. The effectiveness of nine fungicides of different chemical groups to reduce Stemphylium mycelial growth in vitro was tested. Boscalid + pyraclostrobin (group name, succinate dehydrogenase inhibitors + quinone outside inhibitors), iprodione (dicar-boximide), and prochloraz (demethylation inhibitors) were highly effective at reducing mycelial growth in S. vesicarium with EC50 values less than 5 ppm. In general, the effectiveness of the fungicide was enhanced with increasing dosage.

Microfungi on Tamarix

Tamarix species are small trees that grow in various natural habitats and have a wide geographic distribution. Microfungal species previously found on Tamarix and recently collected in Italy and Russia were identified based on morphological characters and analyses of gene sequence data. The sexual morph of the coelomycetous genus Homortomyces was collected for the first time and is described and illustrated. A new family, Homortomycetaceae (Dothideomycetes, families incertae sedis) is introduced to accommodate Homortomyces. Two new genera Neomicrosphaeropsis (Didymellaceae) and Tamaricicola (Pleosporaceae) are introduced in this paper. Phoma tamaricicola was recollected and is placed in Neomicrosphaeropsis based on morphology and molecular data. Ten new species, Cytospora italica, C. unilocularis, Diaporthe ravennica, Eutypella tamaricis, Neomicrosphaeropsis italica, N. novorossica, N. rossica, Keissleriella tamaricicola, Paracamarosporium tamaricis and Tamaricicola muriformis are introduced, while Alternaria tenuissima, Dothiorella sarmentorum, Neofusicoccum luteum, Paraepicoccum amazonense, Pleospora herbarum and Pseudocamarosporium propinquum are reported for the first time on Tamarix spp. with descriptions and illustrations. Multi-gene analyses show that Paraepicoccum amazonense should be placed in Pleosporineae, Pleosporales, where it is closely related to Camarosporium sensu stricto. Several herbarium specimens were studied to illustrate other fungal species recorded on Tamarix species. A comprehensive account of microfungi on Tamarix is provided, which includes a list with data from the literature, as well as those identified in the present study. The taxonomic placement of most taxa discussed in this study is based on a modern taxonomic framework based on analysis of multi-gene sequence data.

First report of Pleospora herbarum causing brown leaf blight of Chinese chive in Japan

Chinese chive ( Allium tuberosum ) is a popular vegetable in Chinese and Korean cuisines. A new disease was observed in four fields during routine disease surveys of Chinese chive conducted in June and September from 2007 to 2012 in …

Responses of soil fungal community to the sandy grassland restoration in Horqin Sandy Land, northern China.

Sandy grassland restoration is a vital process including re-structure of soils, restoration of vegetation, and soil functioning in arid and semi-arid regions. Soil fungal community is a complex and critical component of soil functioning and ecological balance due to its roles in organic matter decomposition and nutrient cycling following sandy grassland restoration. In this study, soil fungal community and its relationship with environmental factors were examined along a habitat gradient of sandy grassland restoration: mobile dunes (MD), semi-fixed dunes (SFD), fixed dunes (FD), and grassland (G). It was found that species abundance, richness, and diversity of fungal community increased along with the sandy grassland restoration. The sequences analysis suggested that most of the fungal species (68.4 %) belonged to the phylum of Ascomycota. The three predominant fungal species were Pleospora herbarum, Wickerhamomyces anomalus, and Deconica Montana, accounting for more than one fourth of all the 38 species. Geranomyces variabilis was the subdominant species in MD, Pseudogymnoascus destructans and Mortierella alpine were the subdominant species in SFD, and P. destructans and Fungi incertae sedis were the dominant species in FD and G. The result from redundancy analysis (RDA) and stepwise regression analysis indicated that the vegetation characteristics and soil properties explain a significant proportion of the variation in the fungal community, and aboveground biomass and C:N ratio are the key factors to determine soil fungal community composition during sandy grassland restoration. It was suggested that the restoration of sandy grassland combined with vegetation and soil properties improved the soil fungal diversity. Also, the dominant species was found to be alternative following the restoration of sandy grassland ecosystems.

Yellow spot of white lace flower caused by Pleospora herbarum in Japan

Yellow spots on leaves of white lace flower, Ammi majus, were found in Chiba Prefecture, Japan, in October 2006. The symptoms later developed into large brown spots. Brown lesions were also observed on the lower stem, and stem rot followed. A fungus was frequently isolated from the lesions, and the symptoms were reproduced after artificial inoculation. The causal fungus was identified as Pleospora herbarum based on morphology and molecular analysis. We named the new disease “yellow spot” (“ouhan-byo” in Japanese).

Graminicolous fungi from Poland. I. Fungi on halophyte Puccinellia distans

The host plant <i>Puccinellia distans</i> was found to be inhabited by the following fungi: <i>Acrospermum graminum, Cladosporium herbarum, Colletotrichum capsici, Dinemasporium slrigosum, Epichloë typhina, Guignardia graminicola, Ophiosphaerella herpotricha, Phaeosphaeria eustoma, Pleospora herbarum, Pyrenophora trichostoma, Puccinia brachypodii var. poae-nemoralis, Acrospermum graminum</i> and <i>Ophiosphaerella herpotricha</i> had not been earlier reported from Poland. On living stromata of <i>Epichloë typhina</i> a mycophilous <i>Alternaria</i> sp. was noted. Mycological data have been used to establish the allocation and relation of the genus <i>Puccinellia</i> with other similar grass genera.

PCR-SSCP-based reconstruction of the original fungal flora of heat-processed meat products

Food processing of spoiled meat is prohibited by law, since it is a deception and does not comply with food safety aspects. In general, spoilage of meat is mostly caused by bacteria. However, a high contamination level of fungi could be also found in some meat or meat products with certain preserving conditions. In case that unhygienic meat is used to produce heat processed products, the microorganisms will be deactivated by heat, so that they cannot be detected by a standard cultivation method. Therefore, this study aimed to develop and apply a molecular biological method—polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP)—to reconstruct the original fungal flora of heat processed meat. Twenty primer pairs were tested for their specificity for fungal DNA. Since none of them fully complied with all study criteria (such as high specificity and sensitivity for fungal DNA; suitability of the products for PCR-SSCP) in the matrix “meat”, we designed a new reverse primer, ITS5.8R. The primer pair ITS1/ITS5.8R amplified DNA from all tested fungal species, but not DNA from meat-producing animals or from ingredients of plant origin (spices). For the final test, 32 DNA bands in acrylamide gel from 15 meat products and 1 soy sauce were sequenced—all originating from fungal species, which were, in other studies, reported to contaminate meat e.g. Alternaria alternata, Aureobasidium pullulans, Candida rugosa, C. tropicalis, C. zeylanoides, Eurotium amstelodami and Pichia membranifaciens, and/or spices such as Botrytis aclada, Guignardia mangiferae, Itersonilia perplexans, Lasiodiplodia theobromae, Lewia infectoria, Neofusicoccum parvum and Pleospora herbarum. This confirms the suitability of PCR-SSCP to specifically detect fungal DNA in heat processed meat products, and thus provides an overview of fungal species contaminating raw material such as meat and spices.

FIRST REPORT OF PURPLE SPOT DISEASE OF ASPARAGUS OFFICINALIS IN TURKEY

In the course of a survey to determine the fungal pathogens of asparagus in Balikesir province (north-western Turkey) brown sunken lesions with dark purple margins were observed on the spears. Pseudothecia and ascospores were looked for in overwin- tering plant debris. Diseased tissues were surface-sterilized in 1% sodium hypochlorite for 2 min and placed on potato dextrose agar medium. The isolated fungus was identified as Stemphylium vesicarium based on morphological traits (Ellis, 1971), i.e. brown, oblong to broadly ellipsoidal and verruculose conidia (20 to 45×15 to 22 μm), with cross and longitudinal septa; pale to light brown conidiophores with a dark smooth or minutely verrucu- lose band; bitunicate and clavate asci (190 to 150×25 to 33 μm); light brown and ellipsoidal ascospores (35 to 45×15 to 22 μm). The identification was confirmed comparing the sequence of a 544 bp product (accession No. JX397964) amplified from the ITS region of the fungus under study by PCR using the primers ITS1/4 (White et al., 1990) with that of a comparable region of S. vesicarium rDNA present in GenBank. Asparagus seedlings (45- day-old) were sprayed with a suspension of 5×104 conidia/ml, then covered with polyethylene bags for 48 h and kept for 21 days at 22±1°C and a 14 h photoperiod. Symptoms comparable to those seen in the field were obtained and the fungus was con- sistently re-isolated from the lesions. S. vesicarium (telemorph, Pleospora herbarum), is an asparagus pathogen first recorded in the USA (Lacy, 1982). To our knowledge, this is the first report of asparagus purple spot disease in Turkey.

RELATIONSHIPS BETWEEN AIRBORNE PLEOSPORA HERBARUM AND ALTERNARIA SP. SPORES IN NO-TILL ASPARAGUS FIELDS

Pleospora herbarum (anamorph Stemphylium vesicarium) is the causal agent of purple spot of asparagus. Airborne concentrations of P. herbarum ascospores and conidia and Alternaria sp. conidia were monitored using a Burkard volumetric spore sampler for three growing seasons in two Michigan no-till asparagus fields. While P. herbarum ascospores and conidia and Alternaria sp. conidia were all detected early in the sampling season, most P. herbarum (greater than 78%) conidia were sampled following the last spear harvest in each field each year. This suggests that conidia were primarily responsible for disease on the fern. Diurnal periodicities were observed for atmospheric concentrations of P. herbarum and Alternaria sp. conidia with peak concentrations from 700 to 1300 h and 900 to 1700 h, respectively. P. herbarum ascosporal concentrations did not follow a diurnal pattern. The concentration of airborne Alternaria sp. conidia was positively correlated with airborne P. herbarum conidia, but not with P. herbarum ascospores. The results of this study suggest that an Alternaria disease forecaster such as FAST or TOM-CAST could be useful to predict disease on asparagus ferns since P. herbarum conidial concentrations were positively correlated with Alternaria sp. conidial concentrations. TOM-CAST has been adopted by most growers in Michigan and has been validated as a useful tool to prompt chlorothalonil applications to 'Jersey' cultivars of asparagus. As the asparagus industry transitions from 'Jersey' to 'Milennium' cultivars, new fungicides become available, and weather parameters not included in TOM-CAST are identified as key for disease development, modification of TOM-CAST may be necessary for satisfactory disease control.

Influence of Environment on Airborne Spore Concentrations and Severity of Asparagus Purple Spot.

Environmental conditions, airborne concentrations of Pleospora herbarum ascospores and conidia, and purple spot disease severity on spears and fern were monitored for 3 years in two no-till asparagus fields in Michigan. Purple spot lesion development on spears was correlated with low temperature and vapor pressure deficit and high rainfall. Low vapor pressure deficit and high rainfall were also correlated with airborne ascospore concentrations at both sites. Lesion development on the fern was favored by longer periods of leaf wetness and low vapor pressure deficit and rainfall. Daily airborne conidia concentrations were positively correlated with average temperature and the number of hours of leaf wetness per day and negatively correlated with vapor pressure deficit. Airborne conidia concentrations displayed a diurnal periodicity with greater concentrations between 700 and 1300 h. The results of this study indicate that a model to predict purple spot on asparagus spears should include temperature, vapor pressure deficit, and rainfall; a model for disease on the fern should include temperature, leaf wetness, vapor pressure deficit, and rainfall.

Pleospora species with Stemphylium anamorphs: a four locus phylogeny resolves new lineages yet does not distinguish among species in the Pleospora herbarum clade

Stemphylium is a genus of plant pathogens and saprobes in the Pleosporaceae (Pleosporales, Dothideomycetes, Ascomycetes). The teleomorphs of Stemphylium, where known, are in Pleospora, with Pleospora herbarum as the type. The goal of this study was to present a rigorous phylogenetic analysis of the relationships among Stemphylium isolates with particular emphasis on species delimitation in the P. herbarum clade, on possible new species and on the relationship of clades to cultures from type specimens. Our taxon sampling comprised 110 Stemphylium strains collected worldwide from various hosts and DNA sequences from four loci, from the ITS, the protein encoding GPD and EF-1 alpha genes and the intergenic spacer between vmaA and vpsA. A large EF-1 alpha intron delimited by noncanonical splice sites and encoding putative proteins was present in three unrelated isolates and was excluded from analyses. Isolates comprised 23 representatives derived from type strains, compared to type strains or otherwise connected to type material, 40 unnamed strains morphologically similar to the type P. herbarum, four strains from an outbreak of Stemphylium leaf blight of cotton in Brazil and eight strains collected in British Columbia mainly from nonagricultural hosts. Our findings provided strong support for the main groupings of Stemphylium obtained earlier and also revealed six possible new species. Other variation within morphological species might point to additional cryptic species. On the other hand, even with four loci, cultures ex-type of five species including P. herbarum were inseparable. We speculate that being self-fertile the clade including P. herbarum might represent a group of highly inbred, morphologically distinct lineages that have yet to accumulate detectable species-specific sequence variation. The lack of variation in P. herbarum clade contrasts with many other a priori defined morphological species where multigene phylogenetic analyses revealed new cryptic species.

Pathogenicity of Stemphylium vesicarium from different hosts causing brown spot in pear

Stemphylium vesicarium (teleomorph: Pleospora herbarum) is the causal agent of brown spot disease in pear. The species is also able to cause disease in asparagus, onion and other crops. Saprophytic growth of the fungus on plant debris is common. The objective of this study was to investigate whether isolates of S. vesicarium from different hosts can be pathogenic to pear. More than hundred isolates of Stemphylium spp. were obtained from infected pear fruits, dead pear leaves, dead grass leaves present in pear orchard lawns as well as from necrotic leaf parts of asparagus and onion. Only isolates originating from pear orchards, including isolates from dead grass leaves, were pathogenic on pear leaves or fruits in bioassays. Non-pathogenic isolates were also present in pear orchards. Stemphylium vesicarium from asparagus or onion, with one exception, were not pathogenic to pear. Analysis of the genetic variation between isolates using Amplified Fragment Length Polymorphism (AFLP) showed significant concordance with host plants. Isolates from asparagus or onion belonged to clusters separate from the cluster with isolates from pear or grass leaves collected in pear orchards. Multilocus sequencing of a subset of isolates showed that such isolates were similar to S. vesicarium.

The family Pleosporaceae: intergeneric relationships and phylogenetic perspectives based on sequence analyses of partial 28S rDNA

The Pleosporaceae is an important loculoascomycete family. There has been disagreement, however, regarding the taxonomic placement of many genera within this family. This study investigates phylogenetic relationships among the genera Cochliobolus, Kirschsteiniothelia, Leptosphaerulina, Macroventuria, Pleospora, Pyrenophora, and Wettsteinina. Partial 28S rDNA sequences from taxa within these genera were analyzed with maximum parsimony, likelihood and Bayesian methods. Cochliobolus can be segregated broadly into two groups as previously proposed. Pleospora is polyphyletic in its current sense. Taxa with Stemphylium anamorphs are closely related to Cochliobolus and fit within the Pleosporaceae, whereas the affinities of Pleospora herbarum and P. ambigua are still ambiguous. Pyrenophora constitutes a monophyletic group within the Pleosporaceae, whereas Leptosphaerulina and Macroventuria appear to share phylogenetic affinities with the Leptosphaeriaceae and Phaeosphaeriaceae. Phylogenies indicate that Wettsteinina should be excluded from the Pleosporaceae. Similar findings are reported for Kirschsteiniothelia, which is probably polyphyletic. Anamorphic characters appear to be significant (especially in Cochliobolus) while ascospore morphologies, such as shape and color and substrate occurrence are poor indicators of phylogenetic relationships among these loculoascomycetes.