Plant Pathology最新文献

{"title":"Meloidogyne hapla dominates plant‐parasitic nematode communities associated with kiwifruit orchards in Portugal","authors":"A. Rita Gonçalves, I. Luci Conceição, Rui P. Carvalho, Sofia R. Costa","doi":"10.1111/ppa.14005","DOIUrl":"https://doi.org/10.1111/ppa.14005","url":null,"abstract":"Kiwifruit, <jats:italic>Actinidia</jats:italic> spp., is an important crop worldwide and its cultivation has been increasing in Portugal. Kiwifruit plants are susceptible to plant‐parasitic nematodes (PPNs), including <jats:italic>Meloidogyne</jats:italic> spp. <jats:italic>M. hapla</jats:italic> and <jats:italic>M</jats:italic>. <jats:italic>incognita</jats:italic> have been reported to affect kiwifruit in major production regions worldwide, although information is lacking on the distribution and identity of PPNs associated with kiwifruit orchards in Portugal. Moreover, research is scarce on the drivers of PPN communities in this crop. Our primary objective was to investigate the diversity, density and distribution of PPNs within kiwifruit orchards of Portugal and to elucidate the influence of environmental factors on their community composition. Additionally, we aimed to evaluate population densities and identity of <jats:italic>Meloidogyne</jats:italic> spp. Nematodes were extracted from composite soil and root samples collected from orchards. Analysis of soil nematode communities suggested bacterial‐driven decomposition and high nutrient enrichment in these soils. Sixteen different genera of PPNs were detected, with <jats:italic>Meloidogyne</jats:italic> spp. as the dominant genus, mostly represented by a single species, <jats:italic>M</jats:italic>. <jats:italic>hapla</jats:italic>. PPN communities exhibited low richness, and β‐diversity analysis indicated a high degree of similarity among them. Additionally, their composition was significantly influenced by soil and climatic parameters. We found that 37 out of 40 kiwifruit orchards in Portugal were infested by root‐knot nematodes. The unexpectedly low species diversity, dominated by <jats:italic>M</jats:italic>. <jats:italic>hapla</jats:italic>, merits further research to establish underlying factors for its high incidence in this crop and to assess the impact of these nematodes on kiwifruit performance and productivity.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"75 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The growth‐promoting effects of Bacillus amyloliquefaciens W82T‐44 on soybean and its biocontrol potential against soybean Phytophthora root rot","authors":"Haixu Liu, Zhuoqun Zhang, Ying Xu, Xiuming Du, Jingzhi Wen","doi":"10.1111/ppa.13994","DOIUrl":"https://doi.org/10.1111/ppa.13994","url":null,"abstract":"The most devastating soilborne disease of soybean is Phytophthora root rot (PRR) caused by <jats:italic>Phytophthora sojae</jats:italic>. Biological control has emerged as an effective method of reducing soilborne diseases. The present study isolated the bacterial strain W82T‐44 from the rhizosphere soil of a resistant soybean variety Williams 82. This strain was identified as <jats:italic>Bacillus amyloliquefaciens</jats:italic> and exhibited a 92.4% inhibition of mycelial growth of <jats:italic>P</jats:italic>. <jats:italic>sojae</jats:italic>. W82T‐44 produced cellulase, siderophore and protease and significantly promoted soybean growth. W82T‐44 treatment, compared to the negative control, was found to significantly (<jats:italic>p</jats:italic> &lt; 0.05) increase soybean plant height (22.34 vs. 18.47 cm), fresh weight of the whole plant (2.57 vs. 2.05 g), dry weight (0.43 vs. 0.32 g), total root length (266.80 vs. 182.53 cm), root area (27.10 vs. 17.84 cm<jats:sup>2</jats:sup>) and root volume (1.88 vs. 1.16 cm<jats:sup>3</jats:sup>). The fermentation filtrate of W82T‐44 had significant inhibitory effects on mycelial growth, oospore formation and cyst germination in <jats:italic>P</jats:italic>. <jats:italic>sojae</jats:italic> and additionally promoted zoospore encystment. W82T‐44 possessed genes involved in lipopeptide synthesis, including bacilysin, surfactin, fengycin and bacillomycin. Moreover, it significantly upregulated pathogenesis‐related genes (β‐1,3‐glucanase, nonexpressor of pathogenesis‐related gene 1, chitinase) and genes encoding defence enzymes (polyphenol oxidase, phenylalanine ammonia‐lyase, peroxidase) in soybean roots (<jats:italic>p</jats:italic> &lt; 0.05). The PRR disease index of soybean treated with the W82T‐44 strain was significantly lower (11.67) than the negative control (40.00; <jats:italic>p</jats:italic> &lt; 0.05). The present study indicates the potential of <jats:italic>B</jats:italic>. <jats:italic>amyloliquefaciens</jats:italic> W82T‐44 as a biological control agent against PRR from various perspectives.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"66 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic diversity and incidence of cassava bacterial blight (CBB) caused by Xanthomonas phaseoli pv. manihotis in Burkina Faso","authors":"Florence Yaméogo, Kevin Ben Fabrice Zerbo, Laurence Blondin, Léonard Ouedraogo, Irenée Somda, Valerie Verdier, Boris Szurek, Issa Wonni","doi":"10.1111/ppa.13989","DOIUrl":"https://doi.org/10.1111/ppa.13989","url":null,"abstract":"Cassava bacterial blight (CBB), caused by <jats:italic>Xanthomonas phaseoli</jats:italic> pv. <jats:italic>manihotis</jats:italic> (Xpm), poses a significant threat to cassava production in Burkina Faso. Prior to this study, the geographical distribution, incidence and origin of CBB introductions were poorly understood. In this investigation, we assessed the incidence of CBB in major cassava‐cropping regions and analysed the genetic diversity of 344 Xpm strains collected from 19 fields between 2015 and 2016, using a multilocus variable number of tandem repeat analysis (MLVA) scheme targeting 14 microsatellite markers. Our results reveal the presence of CBB in three out of four cropping regions, with incidences ranging from 0% to 100% at locality and variety scale. Burkina Faso's Xpm strains exhibited high genetic diversity at multiple levels, including country scale (He = 0.6), cropping region (0.43 to 0.57), locality (0.25 to 0.50) and field (0.25 to 0.52). Pairwise comparisons among populations from different cropping areas indicated a strong genetic differentiation. The categorical minimum spanning tree reveals that the Cascades region has the higher diversity indices and consequently could be the origin site of dispersion of Xpm in the other cropping regions of cassava. Human activities play a major role in the dissemination of Xpm through cassava cuttings. The importance of the sanitary state of cuttings must be emphasized in order to avoid CBB and ensure good cassava production.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"21 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Control of root rot of red raspberries caused by Phytophthora fragariae var. rubi","authors":"N. HEIBERG","doi":"10.1111/j.1365-3059.1995.tb00005.x","DOIUrl":"https://doi.org/10.1111/j.1365-3059.1995.tb00005.x","url":null,"abstract":"The effects of raised beds, mulching, organic amendments and soil treatment with metalaxyl on raspberry root rot (<jats:italic>Phytophthora fragariae</jats:italic> var. <jats:italic>rubi</jats:italic>) were studied in a field experiment with two raspberry cultivars, Veten (highly susceptible) and Chilliwack, a less susceptible cultivar. Raised beds reduced the severity of root rot compared with flat beds. The best results for both cultivars were obtained with a combination of raised beds and metalaxyl treatment. As separate treatments, raised beds and metalaxyl had approximately the same effect. Mulching with grass or composted manure increased the severity of root rot.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"34 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular epidemiology of Cercospora leaf spot on resistant and susceptible sugar beet hybrids","authors":"Chen Chen, Harald Keunecke, Enzo Neu, Friedrich J. Kopisch‐Obuch, Bruce A. McDonald, Jessica Stapley","doi":"10.1111/ppa.13998","DOIUrl":"https://doi.org/10.1111/ppa.13998","url":null,"abstract":"Cercospora leaf spot (CLS), caused by <jats:italic>Cercospora beticola</jats:italic>, is a major foliar disease impacting sugar beet production worldwide. The development of new resistant sugar beet hybrids is a powerful tool to better manage the disease, but it is unclear how these hybrids affect CLS epidemiology. We used a molecular epidemiology approach to study natural epidemics of CLS affecting two susceptible and two resistant sugar beet hybrids at two field sites. Infected plants were geotagged on a weekly basis. Isolations of <jats:italic>C</jats:italic>. <jats:italic>beticola</jats:italic> were made from infected leaves and genotyped using six simple‐sequence repeat loci to identify clones. We determined that CLS epidemics had a later onset in plots planted to resistant hybrids, but once the pathogen established an infection, there was little difference between resistant and susceptible hybrids in the probability of localized spread and dispersal. We found that different clones often infected the same leaf and that clusters of infected plants were often colonized by a mixture of clones. There was little overall difference in genetic diversity of <jats:italic>C</jats:italic>. <jats:italic>beticola</jats:italic> collected on resistant and susceptible hybrids; however, genotypic diversity was lower on the resistant hybrid at one site, suggestive of a selection bottleneck. At the end of the epidemic infections were not randomly distributed across the fields and we found that a single clone could spread over a distance of 100 m during a growing season.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"10 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of grafting tomato onto Solanum torvum on the population dynamics of Meloidogyne incognita and M. javanica and crop yield losses","authors":"Aïda Magdalena Fullana, Alejandro Expósito, Montserrat Pujolà, Isabel Achaerandio, Marina Cunquero, Pablo Loza‐Alvarez, Ariadna Giné, Francisco Javier Sorribas","doi":"10.1111/ppa.13991","DOIUrl":"https://doi.org/10.1111/ppa.13991","url":null,"abstract":"<jats:italic>Meloidogyne</jats:italic> spp. are the most devastating plant‐parasitic nematodes affecting tomato worldwide. Although resistant cultivars and rootstocks are used, selection for virulence occurs in the pathogen. Consequently, using other resistance sources, such as <jats:italic>Solanum torvum</jats:italic>, could improve resistance durability. Several experiments in microplots and plastic greenhouses were carried out to determine the potential use of <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic> as a tomato rootstock to protect against <jats:italic>M</jats:italic>. <jats:italic>incognita</jats:italic> and <jats:italic>M</jats:italic>. <jats:italic>javanica</jats:italic>. In microplots, the relationship between nematode density at transplanting (<jats:italic>Pi</jats:italic>) and multiplication rate did not differ between <jats:italic>Meloidogyne</jats:italic> species in either ungrafted or grafted tomato. However, maximum multiplication rate and maximum density on grafted tomato were 1.27% and 2.93% those on ungrafted, respectively. The grafted tomato plants yielded between 2.9 and 7.5 more times than the ungrafted plants at <jats:italic>Pi</jats:italic> ≥ 100 eggs + J2s per 100 cm<jats:sup>3</jats:sup> of soil, but no differences were observed in plastic greenhouse where a large amount of scion‐rooting occurred. In microplots, the quality of the tomato fruits of ungrafted and grafted plants was affected by the <jats:italic>Pi</jats:italic>. In parallel, some pot experiments were conducted on <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic> and susceptible eggplant to determine the putative selection for nematode virulence to <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic> and the nematode fitness cost. These showed that the nematode subpopulations infected and reproduced less on <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic> than on eggplant. However, the female fertility was only reduced after development of three or four subpopulations on <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic>. Finally, a histopathological study showed that nematode infection and development in <jats:italic>S</jats:italic>. <jats:italic>torvum</jats:italic> was delayed compared to eggplant.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"4 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pathotypes and races of Pseudoperonospora cubensis: Two concepts of virulence differentiation","authors":"Aleš Lebeda, Eva Křístková, Božena Sedláková","doi":"10.1111/ppa.13993","DOIUrl":"https://doi.org/10.1111/ppa.13993","url":null,"abstract":"<jats:italic>Pseudoperonospora cubensis</jats:italic>, causal agent of cucurbit downy mildew, is a common and highly variable pathogen of cucurbit vegetables. Pathogen virulence can be considered on two different levels, that is, pathotypes and races. Pathotypes characterize the interactions between pathogen isolates and the set of genotypes represented by different species and/or genera of the host plant family. Races are characterized by the interactions between pathogen isolates and the set of genotypes (e.g., cultivars, lines, accessions) of one host species (or very closely related species). Differential sets for pathotype and/or race determination are composed of distinct (different) genotypes. Until recently, only differentiation of pathotypes was used to characterize <jats:italic>P</jats:italic>. <jats:italic>cubensis</jats:italic>. Most recent research of virulence variation in <jats:italic>P</jats:italic>. <jats:italic>cubensis</jats:italic> populations in the Czech Republic working with the <jats:italic>Cucumis melo</jats:italic> differential set demonstrated the existence of a large number of races of this pathogen. The differential capacity of this set was primarily created for the determination and denomination of virulence phenotypes/races of cucurbit powdery mildew (<jats:italic>Golovinomyces orontii</jats:italic>, <jats:italic>Podosphaera xanthii</jats:italic>). However, this set is also efficient for differentiating virulence phenotypes in <jats:italic>P</jats:italic>. <jats:italic>cubensis</jats:italic>. This means that one set of <jats:italic>C</jats:italic>. <jats:italic>melo</jats:italic> differential genotypes can be used for two independent plant–pathogen systems: cucurbit powdery mildew and cucurbit downy mildew. Results showed that isolates of <jats:italic>P</jats:italic>. <jats:italic>cubensis</jats:italic> developing identical virulence reaction patterns at the level of pathotype, develop different reaction patterns at the level of races and vice versa. It is demonstrated and explained that pathotypes and races are two different categories for the assessment of virulence variation, which should be clearly defined, recognized and used within international scientific and breeding communities.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"174 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mobile genetic elements of Xylella fastidiosa and their contribution to pathogenicity","authors":"Dennis Jimenez, Diego Beltran, José A. Castillo","doi":"10.1111/ppa.13992","DOIUrl":"https://doi.org/10.1111/ppa.13992","url":null,"abstract":"<jats:italic>Xylella fastidiosa</jats:italic> is a destructive bacterial plant pathogen affecting hundreds of plant families, including important crops such as olive and citrus trees and vines. The pathogenicity of this bacterium rests in a group of genes that encode toxins, enzymes, fimbrial/afimbrial adhesins, cell–cell aggregation proteins and other virulence factors. We investigated the contribution of mobile genetic elements (MGEs) to the pathogenicity of <jats:italic>X. fastidiosa</jats:italic>. Using computational tools, we analysed 94 <jats:italic>X. fastidiosa</jats:italic> genomes corresponding to the three most important subspecies to identify insertion sequences (ISs) and prophages. Results indicate that the distribution and diversity of ISs are modest, with a few families widespread throughout the subspecies of <jats:italic>X. fastidiosa</jats:italic>. The prophages are abundant, and play a more significant role in the pathogenicity of <jats:italic>X. fastidiosa</jats:italic>. Prophages are common in the subspecies of <jats:italic>X. fastidiosa</jats:italic> and contribute to numerous genes related to pathogenicity. The phylogenetic analyses suggest that prophages are recently acquired and that the rearranging of pathogenicity genes triggered by them could generate strains with new pathogenic capacities. Finally, the contribution of MGEs to the pathogenesis of <jats:italic>X. fastidiosa</jats:italic> was evidenced by determining their association with virulence genes using a Bayesian framework for phylogenetic analysis of character evolution.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"23 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological, pathological and phylogenetic analyses identify a diverse group of Colletotrichum spp. causing leaf, pod and flower diseases on the orphan legume African yam bean","authors":"Olaide Mary Ogunsanya, Moruf Ayodele Adebisi, Akinola Rasheed Popoola, Clement Gboyega Afolabi, Olaniyi Oyatomi, Richard Colgan, Andrew Armitage, Elinor Thompson, Michael Abberton, Alejandro Ortega‐Beltran","doi":"10.1111/ppa.13995","DOIUrl":"https://doi.org/10.1111/ppa.13995","url":null,"abstract":"African yam bean (AYB; <jats:italic>Sphenostylis stenocarpa</jats:italic>) is an underutilized legume indigenous to Africa with great potential to enhance food security and offer nutritional and medicinal opportunities. However, low grain yield caused by fungal diseases, including pod blight and leaf tip dieback, deters farmers from large‐scale cultivation. To determine the prevalence of fungal diseases affecting leaves, pods and flowers of AYB, a survey was conducted in 2018 and 2019 in major AYB‐growing areas in Nigeria. Leaf tip dieback, flower bud rot and pod blight were the most common symptoms. Morphological and molecular assays were conducted to identify the causal agents of the observed diseases. In all the samples examined, fungi from eight genera were isolated from diseased leaves, buds and pods. Koch's postulates were fulfilled only for fungi belonging to the <jats:italic>Colletotrichum</jats:italic> genus. Fungi from the other seven genera did not produce disease symptoms in healthy AYB tissues. Several <jats:italic>Colletotrichum</jats:italic> isolates were characterized by sequencing the rDNA internal transcribed spacer (ITS), <jats:italic>glyceraldehyde‐3‐phosphate dehydrogenase</jats:italic>, <jats:italic>calmodulin</jats:italic> and <jats:italic>ApMAT</jats:italic> loci. A combined phylogenetic analysis revealed four <jats:italic>Colletotrichum</jats:italic> species: <jats:italic>C</jats:italic>. <jats:italic>siamense</jats:italic>, <jats:italic>C</jats:italic>. <jats:italic>theobromicola</jats:italic> and <jats:italic>C</jats:italic>. <jats:italic>fructicola</jats:italic>, which were recovered from diseased leaves, and <jats:italic>C</jats:italic>. <jats:italic>truncatum</jats:italic>, recovered from diseased pods and buds. Our results are useful to gear efforts to develop integrated management strategies to control diseases affecting AYB in Nigeria and elsewhere. Availability of such strategies may stimulate greater AYB cultivation, which can contribute to diet diversification, something repeatedly advocated by a range of stakeholders to increase food security and prosperity of smallholder farmers.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"30 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring quantities of Phyllosticta citricarpa inoculum in sweet orange orchards using qPCR and young citrus plants as spore traps","authors":"Régis Oliveira Fialho, Rosana Goncalves Pereira, Leonardo Aparecido Brandão, Elaine Cristina Martins, Isabela Vescove Primiano, Paul Fourie, Providence Moyo, Lilian Amorim, Geraldo José Silva Junior","doi":"10.1111/ppa.13996","DOIUrl":"https://doi.org/10.1111/ppa.13996","url":null,"abstract":"Monitoring of <jats:italic>Phyllosticta citricarpa</jats:italic> (causal agent of citrus black spot [CBS]) inoculum in orchards has previously been performed using volumetric spore traps. However, volumetric traps are nonspecific, and only capture ascospores (not pycnidiospores) of different <jats:italic>Phyllosticta</jats:italic> species. This research aimed to monitor and quantify the DNA of <jats:italic>P</jats:italic>. <jats:italic>citricarpa</jats:italic> using young citrus plants as a spore trap combined with quantitative PCR (qPCR), as well as quantify the number of ascospores and pycnidiospores, and to correlate results with weather variables. Citrus nursery plants were placed as traps under and outside tree canopies during fruit developmental stages (from October to July) in two seasons in commercial ‘Valencia’ sweet orange orchards. DNA was extracted from trap leaves to quantify <jats:italic>P</jats:italic>. <jats:italic>citricarpa</jats:italic> inoculum by qPCR of the ribosomal internal transcribed spacer 1 (ITS1 rRNA) region of <jats:italic>P</jats:italic>. <jats:italic>citricarpa</jats:italic> (Pc‐ITS). Correlations of Pc‐ITS to rainy days, leaf wetness and temperature were performed. Overall, the highest numbers of 400 Pc‐ITS/cm<jats:sup>2</jats:sup> of leaf tissue, which represented up to 12 ascospores or pycnidiospores per cm<jats:sup>2</jats:sup>, were detected on leaves sampled from October to March, regardless of the trap position, season and orchard. Trap plants placed under canopies had up to 20‐fold more Pc‐ITS than those placed outside. Rainy days and leaf wetness were the variables most positively correlated with Pc‐ITS. Both results in the fluctuation of <jats:italic>P</jats:italic>. <jats:italic>citricarpa</jats:italic> inoculum in orchards and the most favourable weather variables associated with inoculum production contribute to better understanding of the critical periods for CBS management in citrus‐growing areas.","PeriodicalId":20075,"journal":{"name":"Plant Pathology","volume":"27 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}