Forest Pathology最新文献

{"title":"First Report of Amylostereum spp. Association With the Woodwasp Sirex obesus Bradley (Hymenoptera: Siricidae) in Brazil","authors":"Lucas A. Benso,&nbsp;Lisandro de P. Pieroni,&nbsp;Bruno C. Rossini,&nbsp;Cláudia H. de Oliveira,&nbsp;Jéssica A. Gabia,&nbsp;Vanessa R. de Carvalho,&nbsp;Silva Renata S. Wilcken,&nbsp;Carlos F. Wilcken,&nbsp;Edson L. Furtado","doi":"10.1111/efp.70034","DOIUrl":"https://doi.org/10.1111/efp.70034","url":null,"abstract":"<p>Woodwasps of the genus <i>Sirex</i> are known to have an obligatory symbiotic relationship with <i>Amylostereum</i> fungi. During oviposition, these wasps inoculate arthrospores of the fungus along with a toxic mucous secretion. As a result, attacked conifer trees can exhibit symptoms of decline and death. The aim of this study was to evaluate the diversity of <i>Amylostereum</i> fungi associated with <i>Sirex obesus</i>. To achieve this, female <i>S. obesus</i> wasps were collected from <i>Pinus</i> plantations in Brazil. The mycangia were removed from the wasps using a stereoscope under aseptic conditions. These structures were subsequently macerated in sterile 0.85% saline solution, and aliquots of the resulting suspension were plated onto PDA medium. Fungal growth was monitored daily, and the colonies were purified and identified by sequencing the ITS-rRNA gene region. As a result, we observed that <i>Amylostereum chailletii</i> and <i>Amylostereum areolatum</i> were present in the mycangia of the dissected wasps, with <i>A. chailletii</i> occurring more frequently (93.3%). The association between <i>A. areolatum</i> and <i>S. obesus</i> still requires further study. This discovery has direct implications for the control of this species of wood wasp and may serve as a basis for future research aimed at developing management strategies.</p>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 4","pages":""},"PeriodicalIF":1.0,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/efp.70034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Methods for Resistance Testing of Fraxinus excelsior Genotypes Against Hymenoscyphus fraxineus","authors":"Elisabeth Schertler,&nbsp;Michael Eisenring,&nbsp;Anouchka Perret-Gentil,&nbsp;Martin M. Gossner,&nbsp;Sophie Stroheker,&nbsp;Vivanne Dubach,&nbsp;Valentin Queloz","doi":"10.1111/efp.70029","DOIUrl":"https://doi.org/10.1111/efp.70029","url":null,"abstract":"<div>\u0000 \u0000 <p>Ash dieback (ADB), caused by the invasive fungus <i>Hymenoscyphus fraxineus,</i> has spread extensively across Europe, resulting in considerable economic and ecological damage to European forests. Resistance screening is crucial for selecting and breeding common ash genotypes that are resistant to the ADB pathogen. This requires a standardised and effective method for infecting ash trees with the pathogen and subsequently measuring the infection success. However, to date, there is a lack of scientifically sound comparisons of available methods. In this study, three different methods for testing the resistance of ash genotypes against <i>H. fraxineus</i> (i.e., stem infections, rachis infections, and spore germination assays) were compared and benchmarked against crown defoliation and stem infection assessments. All three resistance assays were performed on 12 ash genotypes covering a wide intraspecific variation in ADB resistance. Stem infections correlated best with crown defoliation observed in the field. However, this method requires a long preparation time and experimental duration. The easiest and fastest method in terms of preparation and execution was the rachis infection assay. Although not completely equivalent to stem infections, the results of the rachis infection assay significantly correlated with the stem lesion lengths measured. Spore germination assays were also quick to carry out, but the timing of sporulation and the sampling of the leaves, followed by agar-medium preparation, proved to be very difficult to synchronise. Following the very small variations in spore germination rates, there was no significant correlation with the stem lesion lengths measured. To obtain meaningful results on the resistance of ash genotypes to ADB, the stem infection method still proved to be the best and most accurate assay. Although new indirect methods for testing resistance in ash trees are arising (e.g., chemistry, spectroscopy, or genetics), direct resistance testing of ash genotypes remains the basis for resistance and breeding research for ash conservation.</p>\u0000 </div>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryphonectria Canker on Eucalyptus in Florida Reconsidered","authors":"Nam Q. Pham,&nbsp;Brenda D. Wingfield,&nbsp;Seonju Marincowitz,&nbsp;Jeremy T. Brawner,&nbsp;Jiri Hulcr,&nbsp;Michael J. Wingfield","doi":"10.1111/efp.70031","DOIUrl":"https://doi.org/10.1111/efp.70031","url":null,"abstract":"<p>Cryphonectria canker is one of the most important diseases of plantation-grown <i>Eucalyptus</i> spp. in the tropics and Southern Hemisphere. The disease has been known in Florida, USA, for many years, and the causal agents are attributed to two known canker pathogens, <i>Chrysoporthe cubensis</i> (≡ <i>Cryphonectria cubensis)</i> and <i>Microthia havanensis</i> (≡ <i>Endothia havanensis</i>). These identifications were based on morphological characteristics, which are inadequate to recognise cryptic species in the Cryphonectriaceae. In this study, we visited various sites in Florida where <i>Eucalyptus grandis</i> and <i>E. amplifolia</i> trees are cultivated and investigated the presence of cankers. Isolations were made from fungal structures on symptomatic tissues associated with cankers. A total of 41 cultures resembling Cryphonectriaceae spp. were isolated. The isolates were identified based on DNA sequences for the ITS region of the rRNA and sections of the <i>β-tubulin</i> gene, and confirmed as the three species of Cryphonectriaceae, namely <i>Microthia havanensis</i>, <i>Chrysoporthe cubensis</i> and <i>Chrysoporthe doradensis</i>. Of these, <i>Chrysoporthe doradensis</i> was discovered for the first time in the USA. In addition, this study represents the first record of any Cryphonectriaceae on <i>E. amplifolia</i> , a <i>Eucalyptus</i> species that is poorly studied in terms of disease. Pathogenicity trials on <i>Eucalyptus</i> showed that all three Cryphonectriaceae species could cause disease on these trees, with <i>Chrysoporthe</i> spp. being more aggressive. These findings highlight the importance of continuous monitoring and surveillance to detect emerging pathogens and safeguard the sustainability of <i>Eucalyptus</i> in non-native forestry systems.</p>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/efp.70031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144615207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asexual Morph and Molecular Phylogeny of Erysiphe sambuci on Sambucus Hosts in China","authors":"Qucuo Zhuoma,&nbsp;Guoyuan Peng,&nbsp;Mu Wang,&nbsp;Penglei Qiu","doi":"10.1111/efp.70030","DOIUrl":"https://doi.org/10.1111/efp.70030","url":null,"abstract":"<div>\u0000 \u0000 <p>Although <i>Erysiphe sambuci</i> has been documented in Pakistan and China since 1960, detailed asexual characteristics and molecular phylogenetic analyses are still lacking at present. Preliminary morphological identification of <i>Erysiphe</i> species infecting newly collected Chinese <i>Sambucus javanica</i> specimens in this study is in well accord with <i>E. sambuci</i> var. <i>sambuci</i>. Morphological re-examination of the holotype specimen of <i>E. sambuci</i> var. <i>crassitunicatae</i> suggests the chain-like swellings in chasmothecial appendages are not universally present, and the thickened ascus walls are statistically insignificant (1.65–5.2 vs. 1.9–4.5 μm, <i>p</i> = 0.8029) compared with that of <i>E. sambuci</i> var. s<i>ambuci</i> found on <i>S. javanica</i> in this study. Molecular analyses of these two varieties demonstrate that there are only three nucleotide variations in the ITS regions and complete identity in 28S sequences. Phylogenetic reconstruction places both taxa within a single clade with 100% bootstrap support, rejecting infraspecific differentiation. Given the integrated morphological and phylogenetic evidence, we propose to formally reduce var. <i>crassitunicatae</i> to synonymy with <i>E. sambuci</i>. Powdery mildew species with mycelioid chasmothecial appendages found on <i>S. javanica</i> and <i>S. adnata</i> in China should be assigned to <i>E. sambuci</i> without any separation into varieties.</p>\u0000 </div>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144515016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Population Genetics Suggests That the Resurgence of Pine Blister Rust Caused by Cronartium pini in the Landes Forest of France Was Triggered by the Recent Cultivation of Alternate Hosts","authors":"R. Ioos,&nbsp;C. Jeandel,&nbsp;S. Launes,&nbsp;E. Kersaudy,&nbsp;J. Chateau,&nbsp;C. Husson,&nbsp;V. Hormaz-Bastid,&nbsp;J. Aguayo","doi":"10.1111/efp.70028","DOIUrl":"https://doi.org/10.1111/efp.70028","url":null,"abstract":"<div>\u0000 \u0000 <p>Two-needle pine blister rust is caused by <i>Cronartium pini</i>, a fungus that can have one of two forms. One requires an alternate host plant to achieve sexual reproduction and thus complete its life cycle (heteroecious), while the other is able to maintain itself clonally on pines (autoecious). Pine blister rust is widely distributed across Eurasia and may cause significant damage in infected natural forests and plantations. In France, the fungus may cause sporadic, local damage to plantations under certain environmental conditions, such as the presence of wild alternate hosts and particular weather conditions. A recent outbreak of this disease was observed on young pine stands in the Landes forest in South-West France, with prevalence levels reaching up to 80% in some stands. This outbreak emerged contemporaneously with the planting of a large peony field in the middle of young pine plantations. Peonies being one of the many alternate hosts for <i>C. pini</i>, this work aimed to investigate whether the latter was present in its alternating or non-alternating form and to study the relationship between the fungal populations attacking both pine trees and peonies. A total of 522 samples of aecia on pines and 108 samples of uredia on peonies were genotyped in 2021 and 2022 by studying seven microsatellite loci. The results showed that the heteroecious form of <i>C. pini</i> largely predominated in both the populations of the two sites sampled in the Landes forest and at the two more distant sites. In addition, the populations sampled from peonies did not differ genetically from those sampled in the pine plots surrounding them, which suggests that peonies participate in the completion of the biological cycle of <i>C. pini</i> on these sites. On the other hand, the populations in the Landes differ from the populations at the more distant sites in France. This study demonstrates that the establishment of natural hosts in the form of peony crops in the middle of pine plantations allowed the fungus inoculum to multiply in its heteroecious form, to increase the disease pressure and, consequently, the severity of damage to pine saplings. The complete removal of peony plots in late 2023 should help reduce the intensity of the disease in the years to come.</p>\u0000 </div>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144273378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sonic and Electrical Resistivity Tomography of Pinus densiflora Stems Infected with Pine Wood Nematode","authors":"Junhyung Park,&nbsp;Dahye Seo,&nbsp;Hyojun Ahn,&nbsp;Jinwoo Kim,&nbsp;Ki Woo Kim","doi":"10.1111/efp.70027","DOIUrl":"https://doi.org/10.1111/efp.70027","url":null,"abstract":"<p>The structural integrity of tree stems can be evaluated using tomography, a minimally invasive method. We used sonic tomography (SoT) and electrical resistivity tomography (ERT) to compare internal states and electrical properties between healthy and pine wood nematode-infected <i>Pinus densiflora</i> stems. A total of 25 trees, consisting of five healthy and 20 infected trees, were assessed. Both SoT and ERT were performed at 50, 100 and 200 cm above ground level. Heartwood and sapwood electrical resistivity (ER) values were extracted from the tomograms to quantitatively evaluate the ERT results. The SoT results showed that all trees had sound sapwood and heartwood. Significant differences in mean ER were found between the healthy trees (1037.54 Ωm) and infected trees (764.94 Ωm). While the ER of sapwood remained constant in healthy trees, it increased with measurement height in infected trees, and differences in ER between heartwood and sapwood were significantly lower in infected trees than in healthy trees. These ER differences were likely to be attributed to decreases in resin production and changes in microbial communities within the stems of infected trees. These results suggest that SoT and ERT could be used as minimally invasive diagnostic tools for pine wilt disease.</p>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/efp.70027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diaporthe decedens Is the Causal Agent of Canker of Hop Hornbeam (Ostrya carpinifolia) in Tuscany (Italy)","authors":"A. Gionni,&nbsp;F. Pecori,&nbsp;A. Puca,&nbsp;H. Berto,&nbsp;A. L. Pepori,&nbsp;A. Santini","doi":"10.1111/efp.70026","DOIUrl":"https://doi.org/10.1111/efp.70026","url":null,"abstract":"<p>During 2018, extensive European hop-hornbeam (<i>Ostrya carpinifolia</i> L.) diebacks were observed in natural stands in the Apennines (central Italy). Cankers on the stems and branches and crown dieback were the more common symptoms observed, mainly at the beginning of the growing season. In 2023, similar symptoms were reported on the same host species in natural stands in the province of Lucca. Three species were most frequently isolated from the tissues of symptomatic plants: <i>Diaporthe decedens</i>, <i>Dothiorella parva</i> and <i>Pezicula sporulosa</i>. The identity of these species was confirmed through phylogenetic analysis. Their pathogenicity was assessed with two trials performed on 2-year-old hop-hornbeam seedlings and cut shoots. <i>Dothiorella parva</i> and <i>Pezicula sporulosa</i> caused limited necrotic lesions only on cut shoots, while <i>D. decedens</i> showed the higher virulence and aggressiveness, being able to cause extensive cankers in both trials. To our knowledge, this is the first report of <i>D. decedens</i> causing cankers and dieback on <i>O. carpinifolia</i> in Italy or elsewhere. Considering the ecological importance of <i>O. carpinifolia</i> as a pioneer species, further investigations are needed to assess the spread of the disease and the extent of its impact in natural stands.</p>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/efp.70026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Additional Records of Potensaphelenchus stammeri (Nematoda: Aphelenchoididae) in Association With Spondylis buprestoides (Coleoptera: Cerambycidae) Across Europe","authors":"M. L. Inácio,&nbsp;M. Kacprzyk,&nbsp;A. R. Varela,&nbsp;S. Costa,&nbsp;L. Bonifácio","doi":"10.1111/efp.70024","DOIUrl":"https://doi.org/10.1111/efp.70024","url":null,"abstract":"<div>\u0000 \u0000 <p>Since the detection in Portugal of the pinewood nematode (PWN—<i>Bursaphelenchus xylophilus</i>), in 1999, annual field surveys have been conducted to monitor its spread. These surveys include sampling symptomatic and dead pine trees, mainly <i>Pinus pinaster</i> Aiton, to assess and control the pine wilt disease. A complementary approach involves the use of chemical lures to capture insect vectors of the genus <i>Monochamus</i> (Coleoptera, Cerambycidae), the primary PWN carriers. The lure used (Galloprotect 2D Plus) includes specific pheromones for <i>Monochamus</i>, but also pine volatiles and bark beetles' pheromones. As part of a collaborative study, insects caught in traps placed in Portugal (969 insects, during 2023) and Poland (272 insects, during 2024) were surveyed for the presence of nematodes belonging to the Aphelenchida. In both countries, <i>Spondylis buprestoides</i> (Coleoptera, Cerambycidae) were caught (195 and 150 insects, respectively) and were found to be the only carrying vector of <i>Potensaphelenchus stammeri</i> (Nematoda: Aphelenchoididae). The general morphology of both females and males agreed with the original description for <i>P. stammeri</i>, namely the male spicules and the conspicuous morphology of the female tail. Molecular analysis, performed by sequencing the partial 18S rDNA gene, a fragment spanning the interspacer ITS1 and ITS2 regions and the partial 28S rDNA gene, further confirmed the results of the morphological analysis. This finding highlights the unique relationship between <i>P. stammeri</i> and the insect <i>S. buprestoides</i> and their large distribution in Europe.</p>\u0000 </div>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Eucalyptus Canker Diseases in Plantations of Uganda","authors":"Agatha Syofuna,&nbsp;Grace Nakabonge,&nbsp;Abwoli Banana,&nbsp;Christine Betty Nagawa,&nbsp;Susan Balaba Tumwebaze,&nbsp;Enock Ssekuubwa,&nbsp;Mnason Tweheyo","doi":"10.1111/efp.70025","DOIUrl":"https://doi.org/10.1111/efp.70025","url":null,"abstract":"<div>\u0000 \u0000 <p><i>Eucalyptus</i> is one of the most widely grown industrial crops worldwide. This wide distribution comes with many diseases due to the wide exchange of germplasm, and Eucalyptus being a suitable host for indigenous pathogens. <i>Eucalyptus</i> plantations in Uganda are affected by stem canker diseases that have reduced productivity. Therefore, it is crucial to understand the prevalence and distribution of canker diseases among species and clones and regions in order to develop management strategies. A nationwide survey on <i>Eucalyptus</i> canker diseases was conducted in different regions, hereafter clusters, of Uganda. The most prevalent disease in all clusters was Botryosphaeria canker, mainly affecting <i>Eucalyptus grandis</i>, <i>E. camaldulensis</i> and the GU hybrid clone (<i>E. grandis</i> × <i>E. urophylla</i>). However, the most severe disease was Teratosphaeria canker, which affected 50% of the GC hybrid clone (<i>E. grandis</i> × <i>E. camaldulensis</i>). The incidence and severity were highest in the Western and Central Uganda clusters, respectively. The incidence and severity varied significantly with age, with 41% of trees less than 5 years in age being the most affected. Plantations with mixed species, mixed hybrid clones and mixed species with hybrids had the lowest disease incidence and severity compared to monocultures. The findings indicated that, although Botryosphaeria canker was the most prevalent of these diseases, Teratosphaeria canker caused more damage to <i>Eucalyptus</i> plantations in Uganda, with the highest severity recorded in monocultures and clusters characterised by high annual rainfall (1244–1356 mm per year). This information will help <i>Eucalyptus</i> growers carry out site-species matching and select appropriate combinations of species and clones for canker disease management and better yields.</p>\u0000 </div>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No Direct Observational Evidence for Basidiospore-Derived Infection of Eucalypt and Rose Apple (Syzygium jambos) by the Myrtle Rust Pathogen, Austropuccinia psidii, From Brazil","authors":"Rosiane F. Almeida,&nbsp;João Vitor P. V. Ferreira,&nbsp;Vitor M. Sousa,&nbsp;Rafael F. Alfenas,&nbsp;Ned B. Klopfenstein,&nbsp;Acelino C. Alfenas","doi":"10.1111/efp.70023","DOIUrl":"https://doi.org/10.1111/efp.70023","url":null,"abstract":"<p>Myrtle rust caused by <i>Austropuccinia psidii</i> is one of the most important diseases affecting eucalypts (<i>Eucalyptus</i> spp. and <i>Corymbia</i> spp.) in Brazil. Asexual spores of the myrtle pathogen, urediniospores, give rise to infection of young tissues (e.g., leaf, stem, flower and fruit) of the myrtaceous hosts. Symptoms of myrtle rust disease are necrosis and leaf deformation, and death of the apical shoots, whereas the primary diagnostic signs of myrtle rust disease are yellow urediniospores, which are formed by the myrtle rust pathogen on the infected organs. Occasionally, teliospores are formed in brown pustules, usually at higher temperatures on more mature leaves of susceptible hosts, and these teliospores can germinate to produce basidia that produce basidiospores. Previous studies have demonstrated that genetic recombination in <i>A</i>. <i>psidii</i> was associated with basidiospores of the South African and Pandemic biotypes of <i>A. psidii</i> on rose apple (<i>Syzygium jambos</i>). However, it remains unconfirmed whether basidospore-derived infection and genetic recombination also occur within the most damaging biotype of <i>A. psidii</i> in Brazil. Furthermore, direct observation of basidiospore-associated infection by <i>A</i>. <i>psidii</i> has not been previously reported. In this study, we found no evidence of basidiospore germination and/or germ tube penetration into the host tissue of eucalypt (<i>E</i>. <i>urophylla</i>) and rose apple (<i>S. jambos</i>) using scanning electron microscopic observations, raising questions about the role of basidiospores in the life cycle of <i>A</i>. <i>psidii</i> in Brazil.</p>","PeriodicalId":55153,"journal":{"name":"Forest Pathology","volume":"55 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/efp.70023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}