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In late summer 2022 and 2023, powdery mildew symptoms were found on female plants of hemp (Cannabis sativa) growing in a private garden in Hradec nad Moravicí (Silesia, Czech Republic). On the upper sides of the leaves, white powdery colonies were observed which coalesced and finally covered the whole leaf surface. The stems and flowers were not affected. Microscopic examination revealed the formation of asexual (anamorphic) states characterized by conidiophores forming catenescent conidia (Euoidium type), but with two types of conidia, viz., ellipsoid to ovoid or doliiform conidia with fibrosin bodies (resembling conidia of Podosphaera spp.), and ellipsoid to doliiform conidia without fibrosin bodies (resembling conidia of Golovinomyces spp.). Molecular genetic analyses confirmed co‐infections in the studied hemp samples by two powdery mildew species, viz., Podosphaera macularis and Golovinomyces ambrosiae, which represent first records from the Czech Republic, as well as Europe and in the world. The authors discuss the latest information and ideas regarding this pathosystem. [ABSTRACT FROM AUTHOR]

Powdery mildew on oak, caused by Erysiphe spp., has been shown to have serious ecological consequences on a range of Quercus hosts. Erysiphe alphitoides and E. quercicola are two of the most heavily studied and common powdery mildews known to occur on Quercus species. In recent years, these species have been noted throughout the world on a range of hosts within and outside the Quercus genus. Reports that E. alphitoides was absent in European herbaria before 1921 and the discovery of the holotype of E. alphitoides from 1911 in an American herbarium (FH) led to the current study in which we genetically analysed six specimens of E. alphitoides s. lat including, most importantly, the holotype of E. alphitoides from France collected in 1911. The results of our analyses revealed that: (1) The sequence of the E. alphitoides holotype falls within the E. quercicola clade, confirming that E. alphitoides did not spread to Europe until ~1921. (2) E. alphitoides var. chenii forms a monophyletic clade with E. epigena and should be reduced to synonymy with that species and (3) through sequence analyses E. alphitoides and E. quercicola are confirmed to have spread to North America. The sequencing results of the E. alphitoides holotype have severe nomenclatural‐taxonomic consequences. A proposal was submitted simultaneously with the present manuscript to conserve the name E. alphitoides so that the traditional usage of the names E. alphitoides and E. quercicola could be maintained. The sequences obtained for the current study provide new insight into the taxonomy and spread of these ecologically significant, globally distributed species. The present study highlights the importance of sequencing specimens from type material, above all when morphological similar species are involved. [ABSTRACT FROM AUTHOR]

In December 2020, Euphorbia leucocephala plants exhibiting symptoms of powdery mildew were observed in the Botanical Garden of Tuljaram Chaturchand College, Baramati, Maharashtra, India. Based on morphological identification, DNA sequence analysis, and pathogenicity, the fungal pathogen of the disease was identified as Leveillula clavata. This is the first report of L. clavata on Euphorbia leucocephala from India and in general. [ABSTRACT FROM AUTHOR]

Fungal pathogens have the potential to affect plant biogeography and ecosystem processes through their influence on the fitness and functioning of their plant hosts. Simultaneously, changes in plant communities can influence fungal pathogen communities. Exactly which host plant attributes determine the composition of fungal pathogen communities on the leaves remains poorly understood.Here, we characterized foliar fungal pathogen communities in subtropical tree communities along an experimental diversity gradient in Jiangxi, South‐East China. On 32 tree species, we identified all visible fungal structures and symptoms microscopically and studied fungi‐specific traits such as conidia or spores in detail. We asked how different facets of biodiversity, including taxonomic, phylogenetic and functional tree diversity, shape fungal diversity and fungal infestation at different scales.We found a positive relationship between tree richness and fungal richness at the plot level. At the level of individual trees of the same species, the relationship between tree species richness and fungal species richness was marginally significantly negative. Importantly, the fungal infestation rates decreased as tree species richness increased, suggesting that colonization of hosts by specialist fungi was impeded by dilution of the pool of available hosts. Moreover, we found evidence for similar topologies between phylogenetic topologies of trees and fungal genera which is a precondition for coevolution and we identified leaf traits, including leaf habit (deciduous/evergreen), leaf magnesium content and stomata size that predicted fungal richness and infestation.Synthesis. Our study indicates that host tree species harbour different foliar fungal pathogens, which sums up to the highest fungal pathogen richness in more diverse forest stands. At the same time, the foliar fungal pathogen infestation rate for each tree species decreased with increasing tree richness in forests. We identified leaf traits that can help to better predict fungal pathogen richness and infestation, and we show that phylogenetically closely related tree species harbour phylogenetically closely related foliar fungal pathogens. These new insights might be helpful to improve the pest resilience of future forests and plantations. [ABSTRACT FROM AUTHOR]

Erysiphe bulbouncinula (≡ Bulbouncinula bulbosa) on Koelreuteria paniculata is a powdery mildew native and endemic in China. Fresh samples of this species were collected on K. paniculata in Sichuan Province, China, in 2018. This is the fourth confirmed identification of this species. The original description in 1932 was based on one specimen from Hangzhou and then was described in Nanjing in 1990 and in Taiwan in 1993. The morphology of the new collections of this species is described and illustrated in detail, and agrees well with the original description of the type specimen except for the number of asci (8–16 asci per chasmothecia versus 7–9 asci in the type specimen). To explore the phylogenetic position of this poorly known species, three separate phylogenetic analyses, using partial 28S rDNA and the combination of internal transcribed spacer (ITS) and 28S rDNA sequences, were conducted. The results clearly showed that E. bulbouncinula form a monophyletic clade with strong bootstrap (BS) support (MP = 100%) constituting a sister clade to E. gracilis s. lat., form a subclade with Erysiphe sect. Californiomyces and then form a big group with sect. Typhulochaeta and sect. Uncinula. Phylogenetic results confirm that E. bulbouncinula is more closely allied to Erysiphe than to Phyllactinia. Thus, this species can be maintained in Erysiphe in its current circumscription, confirming Bulbouncinula as a synonym of Erysiphe. [ABSTRACT FROM AUTHOR]

Two anamorph-typified names are older than I P. psidii i and threaten this name, viz., I Caeoma eugeniarum i , introduced in 1825, and I Uredo neurophila i , which dates back to early 1884. I Austropuccinia psidii i is an economically important plant disease that threatens cultivated myrtaceous host plants worldwide, above all in Australia and South America (Walker in Austral. The involvement of a name for an important plant disease and its continuous application since 1884 are in favour of the maintenance of the epithet ' I psidii i ', now as I Austropuccinia psidii i . [Extracted from the article]

The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning., We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species., Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species., We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded., Synthesis. For the first time, we experimentally demonstrated that for two common forestry tree species, foliar fungal pathogen richness and infestation depend on local biodiversity. Thus, local tree diversity can have positive impacts on ecosystem functioning in managed forests by decreasing the level of fungal pathogen infestation. [ABSTRACT FROM AUTHOR]

The article focuses on proposals to conserve the teleomorph-typified name Blumeria against the anamorph-typified name Oidium and other 22 teleomorph-typified powdery mildew species names against anamorph-typified that belongs to Ascomycota: Erysiphaceae. It informs that proposals have been sent under the International Code of Nomenclature (ICN) to the General Committee for consideration by the Nomenclature Committee for Fungi and also mentions the names of proposed species.

The grouping of the ex-holotype sequence with I E. quercicola i is in accordance with recently published findings evaluating the invasion of oak powdery mildew in Europe, which suggested that the common oak powdery mildew, previously referred to as I Microsphaera i / I Erysiphe alphitoides i , was not present in European herbaria until 1921; and did not become widespread throughout Europe until after 1960 (Gross & al. in Biol. Invas. 7.1), i.e., the rediscovery of the holotype of I Microsphaera alphitoides i would lead to the use of this name for the powdery mildew that has hitherto been referred to as I Erysiphe quercicola i . [Extracted from the article]

Accordingly, Braun (in Schlechtendalia 3: 52. 1999) recognized the genus I Golovinomyces i . Braun (in IMA Fungus 3: 81-86. 2012) recommended that taxonomists generally give preference to teleomorph-typified names rather than anamorph-typified names for powdery mildews. 1997) divided the genus I Oidium i into subgenera corresponding to the phylogenetically confirmed teleomorph-typified powdery mildew genera, including I Oidium i subg. [Extracted from the article]

Presents a proposal to conserve the name Plectosporium over Spermosporina, an anamorphic fungi. Characteristics of the fungi; Habitat of Spermosporina; Differentiation of the basal cell.

The article reflects on the proposal to conserve Trimmatostroma betulinum or Coniothecium betulinum against the ascomycete Torula stilbospora by scientist S. Hughes. It mentions that Trimmatostroma betulinum is a common hyphomycete found on the bark of fallen branches of Alnus, Pinus and other plant species. It mentions that a conservation of Coniothecium betulinum over Torula stilbospora is proposed to maintain the use of T. betulinum.

The article highlights a proposal to conserve the name Pseudocercospora against Stigmina and Phaeoisariopsis. The authors explained why the names Stigmina, Phaeoisariopsis and Pseudocercospora should be merged. The origins of the names and the characteristics of the species bearing the names are discussed.

Reports on the proposal to conserve the generic name Fusicladium Bonord. against Spilocaea Fr. (Hyphomycetes). Reasons for the proposal to conserve the well-known, larger genus Fusicladium; Rare usage of the name Cycloconium Castagne.