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Quantifying the effect of landscape composition on disease dynamics remains challenging because it depends on many factors. In this study, we used a hybrid process-based/statistical modeling approach to separate the effect of the landscape composition on the epidemiology of banana leaf streak disease (BLSD) from weather and fungicide effects. We parameterized our model with a 5-year dataset, including weekly measures of BLSD on 83 plots in Martinique. After estimating the intrinsic growth parameters of the stage evolution of the disease (SED), we evaluated the dynamic effect of five fungicides. Then, we added the intra- and inter-annual effect on disease dynamics using a generalized linear model. Finally, the whole model was used to assess the annual effect of the landscape on the SED for 11 plots. We evaluated the significance of the landscape composition (proportions of landscape elements in 200-, 500-, 800-, 1,000-m-radius buffer zones) on the landscape effect evaluated with the model. The percentage of hedgerows in a 200-m-radius buffer zone was negatively correlated to the landscape effect, i.e., it acted as a constraint against BLSD spreading and development. The proportion of managed-banana-plants in a 1,000-m-radius buffer zone was negatively correlated to the landscape effect, probably due to a mass effect of fungicide treatments. Inversely, the proportions of forest and the proportion of unmanaged-banana-plants, both in 1,000-m-radius buffer zones, were positively correlated with the landscape effect. Our study provides a holistic approach of the role biotic and abiotic factors play on the dynamics of BLSD.

In November 2019, a severe outbreak of fruit rot was observed in olive orchards in Crete, southern Greece. Symptoms appeared primarily on fruits and stalks, resembling those caused by anthracnose. Typical symptoms were fruit rot, shrinkage, and mummification, associated commonly with stalk discoloration and fruit drop. Disease incidence was estimated at up to 100% in some cases, and an unprecedented increase in olive oil acidity reaching up to 8% (percentage of oleic acid) in severely affected olive groves was recorded. Thirty-two olive groves were then surveyed, and samples of fruit, stalk, leaf, and shoot were collected. Visual, stereoscopic, and microscopic observations revealed several fungi belonging to the genera Alternaria, Botryosphaeria, Capnodium, Colletotrichum, Fusarium, and Pseudocercospora. Fungal infection in fruits was commonly associated with concomitant infestation by the olive fruit fly Bactrocera oleae along with increased air temperature and relative humidity conditions that prevailed in October and November 2019. Twenty representative fungal strains isolated from symptomatic fruits and stalks were characterized by morphological, physiological, and molecular analyses. By internal transcribed spacer regions of ribosomal DNA region and translation elongation factor 1-α gene sequencing analysis, these isolates were identified as Alternaria spp., A. infectoria, Botryosphaeria dothidea, Colletotrichum boninense sensu lato, Fusarium lateritium, F. solani species complex and Stemphylium amaranthi. Pathogenicity tests on punctured fruits revealed that all isolates were pathogenic; however, F. solani isolates along with B. dothidea were the most virulent, and wounds were necessary for efficient fungal infection. Moreover, as few as 10 spores of F. solani were sufficient to cause significant infection in punctured fruits. F. solani was also capable of infecting olive fruits in the presence of B. oleae, with no additional wounding, in artificial inoculation experiments. Moreover, it was capable of colonizing and affecting olive blossoms. Further analyses of olive oil extracted from fruits artificially inoculated with F. solani indicated a significant increase in oil acidity, K232, K270, and peroxide value, whereas total phenol content was significantly decreased. To the best of our knowledge, this is the first report of F. solani associated with olive fruit rot and olive oil degradation worldwide.

The cultivars of the common lilac (Syringa vulgaris) grown in the south of the Russian Far East are not always winter-hardy and are often damaged by fungal diseases due to a very humid climate. A promising trend in the selective breeding of lilacs in Russia is the creation of new breeding material based on the gene pool of the broadleaf lilac (S. oblata) and its hybrids in order to introduce valuable adaptive traits into cultivars. The present work aimed to identify the traits of leaf anatomy in species and cultivars of Syringa resistant and susceptible to Pseudocercospora lilacis, the causative agent of brown leaf spot disease. The study was carried out on the living collection of the Botanical Garden-Institute, Far Eastern Branch, Russian Academy of Sciences (Vladivostok). The leaf anatomical structure of two Syringa species showing different degrees of resistance to P. lilacis in the monsoon climate of the Far East (resistant S. oblata and weakly resistant S. vulgaris, and also their hybrid cultivars) has been analyzed. The differences between species, subspecies, and cultivars are quantitative: they differ in the number of spongy mesophyll layers, the cell height in the f irst layer of palisade mesophyll, the cell height in the upper and lower epidermises, and the thickness of both mesophylls. The interspecif ic hybrids resistant or weakly resistant to P. lilacis (brown leaf spot disease) mainly retain the leaf anatomy structure of the maternal plant. One of the traits determining the resistance of hybrid lilac cultivars is an increased number of spongy mesophyll layers in the leaf blade. The study of leaf anatomy has shown that the four-layered spongy mesophyll leaf parenchyma correlates with the resistance of lilacs from the subsection Euvulgaris to P. lilacis. In S. oblata, this trait is inherited down the maternal line. To establish lilac cultivars resistant to fungal diseases, it is advisable to cross the two species (S. oblata and S. vulgaris) or their cultivars using one of S. oblata subspecies as a maternal plant.Сорта сирени обыкновенной (Syringa vulgaris) на юге российского Дальнего Востока не всегда зимостой- ки, повреждаются грибными болезнями, что связано с избыточной влажностью климата. Перспективным направ- лением отечественной селекции сиреней является создание нового селекционного материала с использованием генофонда Syringa oblata и ее гибридов для введения в культурные сорта ценных адаптивных признаков. Целью ра- боты было выявление анатомических особенностей листьев видов и сортов рода Syringa, устойчивых и восприимчи- вых к возбудителю бурой листовой пятнистости Pseudocercospora lilacis. Исследования проведены на коллекционном материале открытого грунта Ботанического сада-института ДВО РАН. Проанализировано анатомическое строение листа двух видов Syringa, различающихся по устойчивости к P. lilacis в муссонном климате Дальнего Востока: устой- чивого S. oblata и слабоустойчивого S. vulgaris, а также гибридных cортов, полученных на их основе. Различия между видами, подвидами и сортами носят количественный характер: число рядов губчатой паренхимы, высота клеток первого ряда палисадной паренхимы, высота клеток верхней и нижней эпидермы, толщина палисадного и губчато- го слоя. Устойчивые и малоустойчивые к P. lilacis межвидовые гибриды преимущественно сохраняют анатомическое строение листа материнского растения. Одним из определяющих признаков устойчивости гибридных сортов сире- ней является повышенное количество рядов губчатой паренхимы листовой пластинки – признак, передающийся от S. oblata по материнской линии. Создание устойчивых к грибным заболеваниям сортов сиреней целесообразно проводить путем скрещивания видов S. oblata и S. vulgaris или их сортов, используя в качестве материнского рас- тения один из подвидов S. oblata. В ходе исследования анатомии листа установлено, что губчатая ткань из четырех рядов коррелирует с устойчивостью сиреней из подсекции Euvulgaris Schneid. к P. lilacis на юге Приморского края. Этот признак листа S. oblata передается по наследству по материнской линии.

Black Sigatoka, caused by Pseudocercospora fijiensis, is one of the most devastating diseases of banana. In commercial banana‐growing systems, black Sigatoka is primarily managed by fungicides. This mode of disease management is not feasible for resource‐limited smallholder farmers. Therefore, bananas resistant to P. fijiensis provide a practical solution for managing the disease, especially under smallholder farming systems. Most banana and plantain hybrids with resistance to P. fijiensis were developed using few sources of resistance, which include Calcutta 4 and Pisang Lilin. To broaden the pool of resistance sources to P. fijiensis, 95 banana accessions were evaluated under field conditions in Sendusu, Uganda. Eleven accessions were resistant to P. fijiensis. Black Sigatoka symptoms did not progress past Stage 2 (narrow brown streaks) in the diploid accessions Pahang (AA), Pisang KRA (AA), Malaccensis 0074 (AA), Long Tavoy (AA), M.A. Truncata (AA), Tani (BB), and Balbisiana (BB), a response similar to the resistant control Calcutta 4. These accessions are potential sources of P. fijiensis resistance and banana breeding programmes can use them to broaden the genetic base for resistance to P. fijiensis., Eleven banana accessions where symptom progression stopped at stage 2 of symptom progression were identified as potential sources of black Sigatoka resistance that can be used to broaden the genetic base for resistance to P. fijiensis.

The leaf spot disease of Pongamia pinnata caused by an asperisporium-like asexual morph, which is usually referred to as Asperisporium pongamiae, is quite common during monsoon seasons in India. Phylogenetic analyses, based on LSU and rpb2 sequence data, and blast searches using ITS sequence data, revealed that this ascomycete forms a lineage within Mycosphaerellaceae distant from all other generic lineages. Pedrocrousiella gen. nov., with P. pongamiae comb. nov., based on Fusicladium pongamiae (≡ A. pongamiae), as type species is introduced for this lineage. This species has been considered the asexual morph of Mycosphaerella pongamiae (≡ Stigmatea pongamiae). However, this connection is unproven and was just based on the occasional association of the two taxa in some collections. Several attempts to induce the formation of a sexual morph in culture failed, therefore the putative connection between these morphs could not be confirmed. Asperisporium pongamiae-pinnatae is reduced to synonymy with P. pongamiae. Asperisporium pongamiae-pinnatae was introduced because of the wrong assumption that F. pongamiae had been described on another host, Pongamia globosa. But Fusicladium pongamiae was actually described in India on Pongamia glabra, which is a synonym of P. pinnata, and hence on the same host as Asperisporium pongamiae-pinnatae . Pedrocrousiella pongamiae clusters in a clade containing Distocercospora, Clypeosphaerella , and "Pseudocercospora "nephrolepidicola, a species which is not congeneric with Pseudocercospora. Phylogenetically, Pedrocrousiella is distant from the Asperisporium s. str. clade (type species A. caricae), which is more closely related to Amycosphaerella, Pseudocercosporella, Distomycovellosiella and Nothopassalora.

Pseudocercospora haldinae, a new anamorphic foliicolous hyphomycetous fungus discovered on living leaves of Haldina cordifolia (Rubiaceae) is taxonomically described and illustrated. This species is compared with closely related species of Pseudocercospora and other dematiaceous cercosporoid forms reported on the same host genus. The phylogeny of this species has been inferred from partial nuclear ribosomal 28S large subunit (LSU) and complete internal transcribed spacer (ITS) rDNA sequence data. On the basis of LSU, P. haldinae represents characteristic features of Pseudocercospora s. str. and did not form red crystals when cultivated on agar media.

This article provides descriptions and illustrations of microfungi associated with the leaf litter of Celtis formosana, Ficus ampelas, F. septica, Macaranga tanarius and Morus australis collected from Taiwan. These host species are native to the island and Celtis formosana is an endemic tree species. The study revealed 95 species, consisting of two new families (Cylindrohyalosporaceae and Oblongohyalosporaceae), three new genera (Cylindrohyalospora, Neodictyosporium and Oblongohyalospora), 41 new species and 54 new host records. The newly described species are Acrocalymma ampeli (Acrocalymmaceae), Arthrinium mori (Apiosporaceae), Arxiella celtidis (Muyocopronaceae), Bertiella fici (Melanommataceae), Cercophora fici (Lasiosphaeriaceae), Colletotrichum celtidis, C. fici, C. fici-septicae (Glomerellaceae), Conidiocarpus fici-septicae (Capnodiaceae), Coniella fici (Schizoparmaceae), Cylindrohyalospora fici (Cylindrohyalosporaceae), Diaporthe celtidis, D. fici-septicae (Diaporthaceae), Diaporthosporella macarangae (Diaporthosporellaceae), Diplodia fici-septicae (Botryosphaeriaceae), Discosia celtidis, D. fici (Sporocadaceae), Leptodiscella sexualis (Muyocopronaceae), Leptospora macarangae (Phaeosphaeriaceae), Memnoniella alishanensis, M. celtidis, M. mori (Stachybotryaceae), Micropeltis fici, M. ficina (Micropeltidaceae), Microthyrium fici-septicae (Microthyriaceae), Muyocopron celtidis, M. ficinum, Mycoleptodiscus alishanensis (Muyocopronaceae), Neoanthostomella fici (Xylariales genera incertae sedis), Neodictyosporium macarangae (Sordariales genera incertae sedis), Neofusicoccum moracearum (Botryosphaeriaceae), Neophyllachora fici (Phyllachoraceae), Nigrospora macarangae (Apiosporaceae), Oblongohyalospora macarangae (Oblongohyalosporaceae), Ophioceras ficinum (Ophioceraceae), Parawiesneriomyces chiayiensis (Wiesneriomycetaceae), Periconia alishanica, P. celtidis (Periconiaceae), Pseudocercospora fici-septicae (Mycosphaerellaceae), Pseudoneottiospora cannabacearum (Chaetosphaeriaceae) and Pseudopithomyces mori (Didymosphaeriaceae). The new host records are Alternaria burnsii, A. pseudoeichhorniae (Pleosporaceae), Arthrinium hydei, A. malaysianum, A. paraphaeospermum, A. rasikravindrae, A. sacchari (Apiosporaceae), Bartalinia robillardoides (Sporocadaceae), Beltrania rhombica (Beltraniaceae), Cladosporium tenuissimum (Cladosporiaceae), Coniella quercicola (Schizoparmaceae), Dematiocladium celtidicola (Nectriaceae), Diaporthe limonicola, D. millettiae, D. pseudophoenicicola (Diaporthaceae), Dictyocheirospora garethjonesii (Dictyosporiaceae), Dimorphiseta acuta (Stachybotryaceae), Dinemasporium parastrigosum (Chaetosphaeriaceae), Discosia querci (Sporocadaceae), Fitzroyomyces cyperacearum (Stictidaceae), Gilmaniella bambusae (Ascomycota genera incertae sedis), Hermatomyces biconisporus (Hermatomycetaceae), Lasiodiplodia thailandica, L. theobromae (Botryosphaeriaceae), Memnoniella echinata (Stachybotryaceae), Muyocopron dipterocarpi, M. lithocarpi (Muyocopronaceae), Neopestalotiopsis asiatica, N. phangngaensis (Sporocadaceae), Ophioceras chiangdaoense (Ophioceraceae), Periconia byssoides (Periconiaceae), Pestalotiopsis dracaenea, P. formosana, P. neolitseae, P. papuana, P. parva, P. portugallica, P. trachycarpicola (Sporocadaceae), Phragmocapnias betle (Capnodiaceae), Phyllosticta capitalensis (Phyllostictaceae), Pseudopestalotiopsis camelliae-sinensis (Sporocadaceae), Pseudopithomyces chartarum, P. sacchari (Didymosphaeriaceae), Pseudorobillarda phragmitis (Pseudorobillardaceae), Robillarda roystoneae (Sporocadaceae), Sirastachys castanedae, S. pandanicola (Stachybotryaceae), Spegazzinia musae (Didymosphaeriaceae), Stachybotrys aloeticola, S. microspora (Stachybotryaceae), Strigula multiformis (Strigulaceae), Torula fici (Torulaceae), Wiesneriomyces laurinus (Wiesneriomycetaceae) and Yunnanomyces pandanicola (Sympoventuriaceae). The taxonomic placement of most taxa discussed in this study is based on morphological observation of specimens, coupled with multi-locus phylogenetic analyses of sequence data. In addition, this study provides a host-fungus database for future studies and increases knowledge of fungal diversity, as well as new fungal discoveries from the island.

A new species of Pseudocercospora is described causing leaf spot disease on Crotalaria assamica from India. The identity of isolate was based on asexual morphs, cultural characteristics and phylogenetic analyses of partial nuclear ribosomal 28S large subunit and complete internal transcribed spacer rDNA sequence data with high statistical support value. Morphologically this species has characters similar to allied species in genus Pseudocercospora but differs in having catenate and branched conidia. Phylogenetic analysis using LSU and ITS reveals it a new species of Pseudocercospora (Capnodiales, Mycosphaerellaceae).

The taxonomy of 44 specimens of cercosporoid fungi from Hawaii and New York, USA, was elucidated through multi-locus phylogenetic analyses of the LSU and ITS regions of the nrDNA as well as partial sequences of the actin, calmodulin, histone H3, and translation elongation factor 1-α genes. Sequences of four additional loci, namely, partial beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase, the second largest subunit of RNA polymerase II, and the cercosporin facilitator protein-encoding gene, were used to resolve evolutionary species boundaries within the Cercospora beticola species complex using concatenated multi-locus phylogenies and the genealogical divergence index (gdi). Four novel Cercospora species, C. americana sp. nov., C. hawaiiensis sp. nov., C. manoa sp. nov., and C. tecta sp. nov. are described. Neocercospora carotae comb. nov. is made for Cercospora apii var. carotae, which is neotypified. Cercospora cf. citrulina and Pseudocercospora ocimi-basilici are reported for the first time in Hawaii. Cercospora beticola, Pluripassalora bougainvilleae, and Pseudocercospora pittospori are confirmed in Hawaii. Strelitziana africana, isolated from leaves of Ipomoea pes-caprae and Bougainvillea sp. affected by Cercospora spp., is reported for the first time in the USA.

A worldwide survey of cercosporoid ascomycete species on hosts of the genus Diospyros (persimmon) with key to the species based on characters in vivo is provided. Special emphasis is placed on species of the genus Pseudocercospora, which are in part also phylogenetically analysed, using a multilocus approach. Species of the latter genus proved to be very diverse, with a remarkable degree of cryptic speciation. Seven new species are described (Pseudocercospora diospyri-japonicae, P. diospyriphila, P. ershadii, P. kakiicola, P. kobayashiana, and P. tesselata), and two new names are introduced [P. kakiigena (≡ Cylindrosporium kaki, non Pseudocercospora kaki), and Zasmidium diospyri-hispidae (≡ Passalora diospyri, non Zasmidium diospyri)]. Six taxa are lectotypified (Cercospora atra, C. diospyri, C. diospyri var. ferruginea, C. flexuosa, C. fuliginosa, C. kaki), and Pseudocercospora kaki is epitypified.

A cercosporoid fungus associated with leaf lesions of Dypsis lutenscens (Arecaceae) was observed in Chiang Rai, Thailand. This study describes the new species Pseudocercospora dypsidis based on morphological characteristics and phylogenetic analyses from three gene regions, ITS, TEF-1α, and ACT. Single gene analyses are generally insufficient for identification of Pseudocercospora species, or for segregation of other genera in the Pseudocercospora complex. A list is provided of all Pseudocercospora species known from Thailand and the need to confirm their identifications by a polyphasic approach is stressed.

Pseudocercospora rauvolfiicola A. Singh, P.N. Singh and N.K. Dubey sp. nov. Fig 1–4 MycoBank: MB 834637 Etymology. Name refers to Rauvolfia, the host genus from where the fungus was isolated. Culture characteristics – Colonies after 21 days at 27 ° C on Oat Agar (OA) blackish grey, velvety, mycelium sparse, sulcate, reverse blackish grey reaching 30 mm diameter. On Potato Dextrose Agar (PDA) erumpent in centre, margin lobed, grayish black, velvety, reverse black, upto 16 mm. Pathogen on Rauvolfia serpentina Leaf spots dark blackish brown with yellowish encircling area on the upper leaf surfaces, grayish brown on lower surfaces, circular to irregular. Caespituli hypophyllous, substomatal. Mycelium internal, branched. Asexual morph: Stromata substomatal, pseudoparenchymatous, light yellowish brown to light brown, globular, few cells to 13 µm filling stomatal opening, Conidiophores 14–35.5 × 2–3 µm (x̅= 24×3, n=40) macronematous, mononematous, olivaceous brown to light brown, paler towards the tip, fasciculate in divergent fascicles (up to 14), smooth, 0–3 septate, branched, straight to curved, geniculate, sub cylindrical. Conidiogenous cells polyblastic, integrated, terminal, pale olivaceous, smooth, geniculate, scar unthickened. Conidia 9.5–56.5 × 2–3.5 µm (x̅= 36×3 µm, n =40), solitary to branched in chains, acropleurogenous, holoblastic, pale brown, subcylindrical to obclavate, apex obtuse to subacute, base obconico truncate, ramoconidium present, straight to curved, 1–5 septate, hilum unthickened. Type. India, Uttar Pradesh, Sonebhadra, leaf spots on Rauvolfia serpentina (L.) Benth.ex Kurz (Apocynaceae), 15 Dec. 2019, Archana Singh, AMH-10139 (Holotype), BHUAS/19/23 (Isotype), NFCCI 4586 (ex-type living culture), ITS, LSU, ACT and TEF sequences GenBank MT068200.1, MT102882.1, MW496125, MW496126., Published as part of Singh, Archana, Singh, Paras Nath & Dubey, Nawal Kishore, 2022, Morphology and Phylogeny of a new species Pseudocercospora rauvolfiicola on medicinal plant Rauvolfia serpentina from Sonebhadra Forest, Uttar Pradesh, India, pp. 128-138 in Phytotaxa 545 (2) on page 131, DOI: 10.11646/phytotaxa.545.2.2, http://zenodo.org/record/6534639

Pseudocercospora hamiltoniani, a new asexual foliicolous hyphomycetous fungus was discovered on living leaves of Euonymus hamiltonianus (Celastraceae) is described and illustrated. This species is compared with closely related species of Pseudocercospora and other cercosporoid forms reported on the same host genus. The phylogeny of this species has been inferred from internal transcribed spacer (ITS). Phylogenetically, Ps. hamiltoniani differ from closely related Ps. ranjita in having smooth to verruculose mycelium; mostly solitary, highly septate, smooth to verruculose, longer and thicker conidiophores and highly septate with oblique septation, presence of rounded cells, smooth to verruculose, longer and thicker conidia.

Chinese mesona (Platostoma palustre) plays an important role as special crop in Southeast Asia and Taiwan for the production of herbal tea, grass jelly, and further processed food. In order to assess the potential threat of fungi to Chinese mesona, we surveyed isolates from symptomless plants in the area of mesona production, as well as from leaf spots of potted plants in a garden shop and a plantation in a botanical garden in Taiwan. From leaves, stems, and roots of 15 symptomless plants sampled at five collection events over two years, 154 isolates from 810 surface-sterilized plant fragments were obtained and identified based on DNA sequence data of the internal transcribed spacer region, and partially of the β-tubulin and histone H3 genes. The most common species belonged to the genera Cercospora, Colletotrichum, and Fusarium and were considered to be potential plant pathogens. Latent pathogenicity was confirmed by an infection experiment with an endophytic strain of Corynespora cassiicola. Observation of leaf spot disease associated with Cercospora kikuchii suggested pathogenicity of this fungus, which was also isolated as an endophyte from symptomless leaves. We hypothesize that the most common endophytic fungi are latent pathogens in the host and may cause plant disease when the host becomes weakened by senescence or changed cultivation condition. Leaf spots of plants in the botanical garden were associated with a species of Pseudocercospora, which was not found among the endophytic isolates and is newly described based on morphology and analysis of translation elongation factor 1 alpha gene sequences.

Using stereo- and light microscopy, two leaf-spotting cercosporoid fungi, collected from areas of the Brazilian Atlantic Forest in the states of Minas Gerais and Rio de Janeiro, were shown to represent two new species (Pseudocercospora seropedicensis on Solanum asperum and P. solani-cernui on S. cernuum), which are herein described and illustrated.

This article provides morphological descriptions and illustrations of microfungi associated with the invasive weed, Chromolaena odorata, which were mainly collected in northern Thailand. Seventy-seven taxa distributed in ten orders, 23 families (of which Neomassarinaceae is new), 12 new genera (Chromolaenicola, Chromolaenomyces, Longiappendispora, Pseudocapulatispora, Murichromolaenicola, Neoophiobolus, Paraleptospora, Pseudoroussoella, Pseudostaurosphaeria, Pseudothyridariella, Setoarthopyrenia, Xenoroussoella), 47 new species (Aplosporella chromolaenae, Arthrinium chromolaenae, Chromolaenicola chiangraiensis, C. lampangensis, C. nanensis, C. thailandensis, Chromolaenomyces appendiculatus, Diaporthe chromolaenae, Didymella chromolaenae, Dyfrolomyces chromolaenae, Leptospora chromolaenae, L. phraeana, Longiappendispora chromolaenae, Memnoniella chromolaenae, Montagnula chiangraiensis, M. chromolaenae, M. chromolaenicola, M. thailandica, Murichromolaenicola chiangraiensis, M. chromolaenae, Muyocopron chromolaenae, M. chromolaenicola, Neomassarina chromolaenae, Neoophiobolus chromolaenae, Neopyrenochaeta chiangraiensis, N. chromolaenae, N. thailandica, N. triseptatispora, Nigrograna chromolaenae, Nothophoma chromolaenae, Paraleptospora chromolaenae, P. chromolaenicola, Patellaria chromolaenae, Pseudocapulatispora longiappendiculata, Pseudoroussoella chromolaenae, Pseudostaurosphaeria chromolaenae, P. chromolaenicola, Pseudothyridariella chromolaenae, Pyrenochaetopsis chromolaenae, Rhytidhysteron chromolaenae, Setoarthopyrenia chromolaenae, Sphaeropsis chromolaenicola, Tremateia chiangraiensis, T. chromolaenae, T. thailandensis, Xenoroussoella triseptata, Yunnanensis chromolaenae), 12 new host records, three new taxonomic combinations (Chromolaenicola siamensis, Pseudoroussoella elaeicola, Pseudothyridariella mahakashae), and two reference specimens (Torula chromolaenae, T. fici) are described and illustrated. Unlike some other hosts, e.g. bamboo (Poaceae) and Pandanaceae, the dominant group of fungi on Siam weed were Dothideomycetes. Only 15 species previously recorded from northern Thailand were found in this study. Most of the taxa are likely to have jumped hosts from surrounding plants and are unlikely to be a specialist to Siam weed. Most fungal families found on Siam weed had divergence estimates with stem ages in the Cretaceous, which coincided with the expected origin of the host family (Asteraceae). This further indicates that the species have jumped hosts, as it is unlikely that the taxa on the alien Siam weed came from the Americas with its host. They may, however, have jumped from other Asteraceae hosts. In a preliminary screening 40 (65%) of the 62 species tested showed antimicrobial activity and thus, the fungi associated with C. odorata may be promising sources of novel bioactive compound discovery. We provide a checklist of fungi associated with C. odorata based on the USDA Systematic Mycology and Microbiology Laboratory (SMML) database, relevant literature and our study. In total, 130 taxa (116 identified and 14 unidentified species) are distributed in 20 orders, 48 families, and 85 genera. Pseudocercospora is the most commonly encountered genus on Siam weed.

International audience; Understanding the mechanisms involved in pathogen adaptation to quantitative resistance in plants has a key role to play in establishing durable strategies for resistance deployment, especially in perennial crops. The erosion of quantitative resistance has been recently suspected in Cuba and the Dominican Republic for a major fungal pathogen of such a crop: Pseudocercospora fijiensis, causing black leaf streak disease on banana. This study set out to test whether such erosion has resulted from an adaptation of P. fijiensis populations, and to determine whether or not the adaptation is local. Almost 600 P. fijiensis isolates from Cuba and the Dominican Republic were sampled using a paired-population sampling design on resistant and susceptible banana varieties. A low genetic structure of the P. fijiensis populations was detected in each country using 16 microsatellite markers. Cross-inoculation experiments using isolates from susceptible and resistant cultivars were carried out, measuring a quantitative trait (the diseased leaf area) related to pathogen fitness on three varieties. A further analysis based on those data suggested the existence of a local pattern of adaptation to resistant cultivars in both of the study countries, due to the existence of specific (or genotype by genotype) host-pathogen interactions. However, neither cost nor benefit effects for adapted populations were found on the widely used "Cavendish" banana group. These results highlight the need to study specific host-pathogen interactions and pathogen adaptation on a wide range of quantitative resistance phenotypes in banana, in order to develop durable strategies for resistance deployment.

A distinct black leafspot with fungal growth was found on Platanus orientalis ‘Digitata’ (cut-leaf oriental plane tree) in northern Sydney, New South Wales, Australia, in February 2019. Morphological characteristics, internal transcribed spacer sequencing and phylogenetic analysis of the associated fungus identified it as Pseudocercospora platanigena (= Stigmina platani). This pathogen has previously been reported from Pl. orientalis (oriental plane tree) in Europe and Asia and more recently from Pl. orientalis ‘Digitata’ in New Zealand. This is the first report of Ps. platanigena in Australia. Pseudocercospora platanigena is now common on Pl. orientalis ‘Digitata’ throughout Sydney and has been found as far north as Dorrigo in northern New South Wales and west to the Blue Mountains. Pseudocercospora platanigena has not been observed on Pl. orientalis other than the cultivar ‘Digitata’, nor on the more commonly planted London plane tree (Pl. x acerifolia) in Australia. It has not been found in other states in Australia.