Plant disease最新文献

{"title":"High-throughput qPCR phenotyping of Verticillium stripe resistance in <i>Brassica napus</i> under natural field infection.","authors":"Mohamed Samir Youssef, Sean Walkowiak, Christian Obermeier, Isobel A P Parkin, Sally Lynne Vail, Robert W Duncan, Harmeet Singh Chawla","doi":"10.1094/PDIS-06-26-1149-RE","DOIUrl":"https://doi.org/10.1094/PDIS-06-26-1149-RE","url":null,"abstract":"<p><p>Verticillium stripe, caused by Verticillium longisporum, is an emerging threat to Brassica napus production in North America, with increasing field incidence and yield loss reported in affected regions. Although visual ratings are useful for rapid field assessment, resistance breeding is constrained by the lack of scalable, objective phenotyping methods that can quantify pathogen colonization across large genotype panels under field conditions. Here, we adapted and validated an established OLG70/OLG71-based SYBR Green qPCR assay within a high-throughput workflow combining freeze-dried hypocotyl sampling and magnetic bead-based DNA extraction to quantify V. longisporum DNA in field-grown B. napus. A panel of 215 B. napus genotypes was evaluated at two naturally infested field sites in Manitoba, Canada. The assay produced robust standard curves across plates, with R² values >0.99, amplification efficiencies of 95-105%, and low intra-plate variability, supporting reliable quantification over a broad dynamic range. Log₁₀-transformed fungal DNA quantities showed strong cross-environment consistency, with genotype rankings largely conserved between sites (Spearman ρ = 0.82). At the Glenlea site, qPCR-derived fungal load was strongly associated with visual Verticillium stripe severity (Spearman ρ = 0.68; R² ≈ 0.44; Kruskal-Wallis P = 1.59 × 10⁻¹⁷), indicating that hypocotyl colonization measured by qPCR captures biologically meaningful variation in disease expression. This scalable qPCR-based platform provides a repeatable, high-resolution phenotype for large-scale germplasm screening and future genetic analyses aimed at improving Verticillium stripe resistance in canola.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148930893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal changes in the population structure of the pathogen <i>Globisporangium irregulare</i> in a hydroponic Eustoma production system in Japan.","authors":"Ayaka Hieno, Kazuma Morita, Kayoko Otsubo, Wenzhuo Feng, Haruhisa Suga, Koji Kageyama","doi":"10.1094/PDIS-03-26-0634-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-26-0634-RE","url":null,"abstract":"<p><p>Temporal changes in the population structure of <i>Globisporangium irregulare</i> were investigated over three years (2015-2017) in a hydroponic Eustoma production system in Fukushima, Japan. The aims of this study were to determine the phylogenetic affiliation of Fukushima isolates, their potential as a source of contamination, and whether any specific molecular types were associated with pathogenic traits. Phylogenetic analyses based on genetic distances revealed that isolates exhibiting an intermediate RAPD DNA group I/II genotype occupied phylogenetic positions between groups I and II, suggesting recombination across lineages. The 2015 population exhibited relatively high genetic diversity, whereas isolates in 2016-2017 were genetically more uniform and often shared identical genotypes across cultivation cycles. These results indicate that pathogen populations were likely maintained within the hydroponic system, probably via infected plant residues, rather than repeatedly being introduced from the surrounding environment. No clear association was detected between molecular type and pathogenicity-related characteristics. Extracellular enzyme activity analysis revealed increased cellulase and xylanase activities with time while a reverse trend was seen in pectinase activity. However, these year-related trends did not correlate with disease severity. Isolates dominant after 2015 showed lower heat tolerance and reduced zoospore productivity compared with the 2015 population. The observed genotype replacement therefore appears to reflect selection for persistence within the hydroponic environment rather than increased virulence, stress tolerance, or dispersal ability. These results suggest that disease management in hydroponic Eustoma production should consider the potential for long-term survival within cultivation facilities and emphasize the importance of sanitation and residue management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148930817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Clay-Azoxystrobin and <i>Trichoderma</i>-Based Treatments for Managing <i>Magnaporthiopsis maydis</i> Maize Late Wilt Disease.","authors":"Elhanan Dimant, Peleg Hadari, Ofir Degani","doi":"10.1094/PDIS-03-26-0587-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-26-0587-RE","url":null,"abstract":"<p><p><i>Magnaporthiopsis maydis</i>, the causal agent of maize late wilt disease (LWD), is a destructive soil-borne pathogen for which effective and sustainable control remains challenging. We evaluated an integrated management strategy combining clay-based azoxystrobin formulations with <i>Trichoderma</i>-based seed coating in two maize hybrids differing in susceptibility to LWD: the highly susceptible sweet maize hybrid Prelude and the moderately susceptible fodder hybrid Colossus. Bentonite- and sepiolite-based azoxystrobin formulations were applied alone or with two <i>Trichoderma</i> mixtures under net-house conditions. Based on an in vitro assay, <i>T. asperellum</i>, <i>T. longibrachiatum</i>, and <i>T. virens</i>, which inhibited pathogen growth by 37 to 53%, were selected and combined. At the latent mid-season stage, treatment effects on plant growth were limited, but qPCR showed that pathogen DNA levels in infected, untreated Prelude plants were up to 24-fold higher than in Colossus. In Prelude, several treatments reduced pathogen DNA to 2-9% of the infected control. By the end of the season, treatment efficacy became more pronounced. In Colossus, bentonite-azoxystrobin alone or combined with <i>Trichoderma</i>-based seed coating performed best, increasing shoot weight by 62 to 67%, cob weight by 85 to 90%, and health indices by 52 to 67% relative to the infected control. In Prelude, <i>Trichoderma</i>-based seed coating combined with sepiolite-azoxystrobin produced the strongest response, increasing shoot and cob weight by 116 and 145%, respectively. Across both cultivars, clay-based formulations, alone or combined with biological treatment, reduced pathogen DNA to near zero. These findings support this integrated approach for LWD management under net-house conditions, pending field validation.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148930809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Fusarium oxysporum</i> f. sp. <i>crypti</i>, a novel forma specialis causing Fusarium wilt of mitsuba, <i>Cryptotaenia japonica</i>.","authors":"Hiroki Saito, Koji Tobata, Yukiko Kato, Shunsuke Kotera, Shuta Asai, Chiyusa Ishihara, Shunsuke Miyashima, Atsushi Takeda, Yasuaki Morita, B Gillian Turgeon, Antonio Di Pietro, Ken Komatsu, Tsutomu Arie","doi":"10.1094/PDIS-06-26-1146-RE","DOIUrl":"https://doi.org/10.1094/PDIS-06-26-1146-RE","url":null,"abstract":"<p><p><i>Fusarium oxysporum</i> isolates causing Fusarium wilt in mitsuba (<i>Cryptotaenia japonica</i> Hassk.; also referred to as Japanese honeywort, Japanese honewort, or Japanese parsley) have traditionally been classified as f. sp. <i>apii</i>. However, some reports have indicated that the host-pathogenic <i>F. oxysporum</i> isolates derived from mitsuba are nonpathogenic to celery, the principal host of f. sp. <i>apii</i>. In this study, we aimed to elucidate the differences among isolates from mitsuba, coriander, and celery in terms of host range, phylogenetic relationships, genomic synteny, and effector profiles. Inoculation assays revealed a clear distinction in host range between the mitsuba, coriander, and celery isolates. Phylogenetic analyses based on the rDNA intergenic spacer and translation elongation factor sequences indicated a distant relationship between mitsuba isolates and those from coriander and celery. Whole-genome analysis based on high-quality de novo-assembled genomes, including telomere-to-telomere-level assemblies of isolates from mitsuba, coriander, and celery, showed that the mitsuba isolates possess conserved accessory chromosomal regions absent in celery and coriander isolates. Moreover, effector profiling identified a specific pattern of effector repertoires shared by the mitsuba isolates. These findings suggest that the host-pathogenic <i>F. oxysporum</i> isolates derived from mitsuba represent a forma specialis distinct from f. sp. <i>apii</i>. Thus, we propose designating the <i>F. oxysporum</i> isolates from mitsuba that cause Fusarium wilt as <i>Fusarium oxysporum</i> f. sp. <i>crypti forma specialis nova</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148930819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of fermentation conditions for <i>Trichoderma hamatum</i> T2 and its efficacy against larch shoot blight caused by <i>Neofusicoccum laricinum</i>.","authors":"Fanghong Liu, Xiaoshuang Song, Yingying Qian, Banghao Wang, Wenfeng Cui, Boru Zhou, Xun Deng","doi":"10.1094/PDIS-05-26-0925-RE","DOIUrl":"https://doi.org/10.1094/PDIS-05-26-0925-RE","url":null,"abstract":"<p><p>Trichoderma hamatum T2 is an antagonistic fungus with biocontrol potential. In this study, single-factor experiments combined with response surface methodology were employed to optimize liquid fermentation conditions for T2, in order to enhance its inhibitory efficacy against Neofusicoccum laricinum, the causal pathogen of larch shoot blight. Using Rose Bengal medium as the basal medium, key fermentation factors, including carbon source, nitrogen source, inorganic salts, and culture conditions, were optimized. Under the optimized fermentation conditions, the sterile fermentation filtrate of T. hamatum T2 exhibited an inhibition rate of 78.8% against N. laricinum, compared with 28.0% obtained using the unoptimized PDA medium. In pot experiments, T2 treatment reduced disease incidence from 76.67% to 16.67%, with a control efficacy of 78.26%. In field trials, the control efficacies were 53.33% in 2024 and 60.26% in 2025. Following pathogen inoculation, T2 treatment significantly increased POD and SOD activities in larch needles, and promoted the accumulation of flavonoids and total phenols. T2 treatment also elevated GR activity, as well as the contents of non-structural carbohydrates, soluble sugars, starch, and proline. Response surface methodology effectively optimized the fermentation conditions of T2. This fungus enhances host resistance by inducing the plant antioxidant system and secondary metabolism, exhibiting promising potential for the biological control of larch shoot blight.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148881143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fungal Diseases Associated with Robusta Coffee (<i>Coffea canephora</i>) in Southern Thailand: Symptom Diversity, Pathogen Characterization, and Environmental Drivers.","authors":"Wanida Petlamul, Sawai Boukaew, Karistsapol Nooprom, Amornrat Chumthong","doi":"10.1094/PDIS-07-26-1384-RE","DOIUrl":"10.1094/PDIS-07-26-1384-RE","url":null,"abstract":"<p><p>Robusta coffee (Coffea canephora) production in tropical regions is increasingly constrained by fungal diseases associated with complex pathogen interactions and favorable environmental conditions. This study investigated symptom diversity, pathogen composition, pathogenicity, and environmental drivers associated with fungal infections in Robusta coffee plantations in southern Thailand. Field surveys were conducted in three commercial plantations located in Thung Lan Subdistrict, Khlong Hoi Khong District, Songkhla Province, Thailand, during February-July 2025. A total of 90 coffee trees were assessed using a stratified sampling approach, and disease symptoms affecting leaves, branches, flowers, and fruits were recorded. Nineteen representative disease symptoms were identified and grouped into major disease categories, including dieback complex, fruit rot/lesion complex, and leaf spot complex. The dieback complex exhibited the highest disease incidence and severity (65.4 ± 5.2% incidence; 58.7 ± 4.3% severity), followed by fruit rot/lesion complex (42.7 ± 4.8% incidence; 36.5 ± 3.8% severity) and leaf spot complex (38.2 ± 3.9% incidence; 29.8 ± 2.7% severity). A total of 10 morphologically distinct fungal isolates were recovered from symptomatic tissues. Molecular analyses identified Fusarium falciforme (95.41%), Lasiodiplodia/Diplodia sp. (99.37%), Lasiodiplodia theobromae (99.79%), and Lasiodiplodia sp. (81.35%). Pathogenicity assays demonstrated that all representative isolates induced disease symptoms on detached Robusta coffee leaves. Among them, F. falciforme showed the highest aggressiveness, producing lesions up to 4.73 cm within 7 days after inoculation. Environmental monitoring further indicated that elevated humidity and moderate temperature during the rainy season favored fungal disease development. These findings demonstrate that fungal diseases in Robusta coffee are driven by multi-pathogen interactions shaped by humid tropical environments, providing an important basis for integrated disease management and sustainable coffee production under changing climatic conditions.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148881134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal Growth Stage for Applying Fungicide on <i>Brassica carinata</i> to Protect Against Yield Loss Resulting From Sclerotinia Stem Rot.","authors":"Rebecca L Barocco, Ramdeo Seepaul, Kira L Bowen, G Kelly O'Brien, Ian M Small","doi":"10.1094/PDIS-06-25-1313-RE","DOIUrl":"10.1094/PDIS-06-25-1313-RE","url":null,"abstract":"<p><p>Carinata (<i>Brassica carinata</i>) is an oilseed crop gaining global attention as a sustainable biofuel feedstock. Sclerotinia stem rot (SSR), caused by <i>Sclerotinia sclerotiorum</i>, has been identified as a major disease of concern for carinata in the Southeastern United States. This study determined the optimal growth stage for a single fungicide application to control SSR and evaluated the relationship between SSR severity and seed yield among multiple varieties. A field trial was conducted over four seasons at the University of Florida Institute of Food and Agricultural Sciences North Florida Research and Education Center in Quincy. Treatments were arranged in a randomized complete block split-plot design with variety as the whole plot and the fungicide (Proline) application timing as the subplot. A disease severity index (DSI) was calculated from SSR assessments at several growth stages. The final DSI in nontreated plots increased from an average of 13.2 (±10.1 SD) in 2018 and 12.5 (±11.1 SD) in 2019 to an average of 49.2 (±16.5 SD) in 2020 that remained at 40.4 (±10.9 SD) in 2021. The correlation of yield with DSI was significant (<i>P</i> ≤ 0.01) for varieties AGR044-321E (<i>r</i> = -0.49), Avanza 641 (<i>r</i> = -0.59), DH-040.342 (<i>r</i> = -0.28), and M-01 (<i>r</i> = -0.62). Early to full flowering was the optimal growth stage for a fungicide application to manage SSR on carinata, but seasonal differences in disease affected the magnitude of control. Effective management using well-timed fungicide applications can support the sustainability of carinata as a biofuel crop.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3727-3736"},"PeriodicalIF":2.8,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147344847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal Population Genetic Dynamics of Wheat Sharp Eyespot Pathogen <i>Rhizoctonia cerealis</i> in the Willamette Valley, Oregon, U.S.A.","authors":"Jiang Liu, Hilary Gunn, Christopher C Mundt","doi":"10.1094/PDIS-12-25-2589-RE","DOIUrl":"10.1094/PDIS-12-25-2589-RE","url":null,"abstract":"<p><p>Wheat sharp eyespot, caused by the soilborne basidiomycete <i>Rhizoctonia cerealis</i> anastomosis group DI (AG-DI), has become an increasingly important stem disease worldwide and has resulted in yield losses in the Willamette Valley of Oregon since 2014. However, the temporal genetic dynamics of <i>R</i>. <i>cerealis</i> populations remain poorly understood. In this study, 440 pure isolates of <i>R</i>. <i>cerealis</i> AG-DI were isolated from the same experimental field in the springs of 2017, 2019, 2021, and 2023. Population genetic analyses based on six microsatellite markers detected no population differentiation among years. The two previously reported genetic pools neither merged nor produced new pools, indicating a stable population structure over time. Together with earlier reports of <i>R</i>. <i>cerealis</i> population genetics from China, these findings suggest that the <i>R</i>. <i>cerealis</i> population in the Willamette Valley was consistent with a founder effect. Although Hardy-Weinberg disequilibrium and linkage disequilibrium tests indirectly indicate the presence of sexual recombination, these signals may represent historical variation rather than substantial ongoing sexual reproduction within the region. The temporal genetic changes observed in the <i>R</i>. <i>cerealis</i> population may be linked to indirect selection pressure imposed during long-term breeding and screening of eyespot (strawbreaker foot rot)-resistant wheat cultivars in the same field. These findings provide insight into the evolutionary processes shaping <i>R</i>. <i>cerealis</i> populations and have implications for disease management and resistance breeding.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3744-3755"},"PeriodicalIF":2.8,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147366582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain Diversity and Resistance to Cucumber Green Mottle Mosaic Virus (CGMMV) in Cucumber.","authors":"Esperanza Gea-Caballero, Livia Donaire, Almudena Castillo, Jesus Abad, Miguel A Aranda","doi":"10.1094/PDIS-07-25-1348-RE","DOIUrl":"10.1094/PDIS-07-25-1348-RE","url":null,"abstract":"<p><p>Cucumber green mottle mosaic virus (CGMMV) is a tobamovirus that causes disease in cucumber crops worldwide, leading to significant economic losses. To study the variability of CGMMV in southeastern Spain, partial genome sequences were obtained from isolates collected in 2017 and 2020 from cucumber crops. Phylogenetic analyses revealed that isolates clustered into two major groups, Asian (AS)-like and European (EU)-like CGMMV isolates. These two groups coexisted in the same area, crops, and even individual plants, although the AS type predominated. The accumulation and symptom expression of molecularly cloned isolates from these two groups were assessed in two cucumber cultivars (resistant and susceptible) under both summer and winter conditions. An in planta antagonistic interaction was detected between the AS and EU isolates, in which the accumulation of CGMMV-EU was suppressed during mixed infections. A multivariate analysis did not identify statistically significant differences because of variations in environmental conditions. Unlike CGMMV-EU, CGMMV-AS did not show significant differences in accumulation based on the plant genotype. To further investigate this, the response to CGMMV-AS infection was analyzed in additional susceptible and resistant cultivars. All cultivars appeared to be similarly susceptible to CGMMV-AS, in contrast to CGMMV-EU, which accumulated to a much lower extent in resistant compared with susceptible plants. These results reinforce the need to continue epidemiological surveillance, identify new sources of resistance, and implement strict control of infected seed trade, given the growing threat that CGMMV-AS isolates pose to cucumber cultivation.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"3777-3788"},"PeriodicalIF":2.8,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147366553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Genomic Regions Associated with Multifungicide Resistance in <i>Botrytis cinerea</i> and Factors Impacting Greenhouse Population Structure.","authors":"Nicole T Lukasko, Soumya Moonjely, Mary K Hausbeck","doi":"10.1094/PDIS-11-25-2230-RE","DOIUrl":"10.1094/PDIS-11-25-2230-RE","url":null,"abstract":"<p><p>The fungal plant pathogen <i>Botrytis cinerea</i> affects hundreds of valuable crops, including fruits, vegetables, and ornamental plants. In greenhouse production systems, <i>B. cinerea</i> disease management largely depends on the use of fungicides; however, the emergence of resistance to multiple fungicide classes has become a major challenge. An improved understanding of <i>B. cinerea</i> populations can contribute to the development of resistance management strategies. In this study, isolates (<i>n</i> = 276) of <i>B. cinerea</i> were collected from ornamental production greenhouses in Michigan, and whole-genome resequencing was performed to evaluate genetic differentiation among hosts, locations, growing cycles, and fungicide resistance. Discriminant analyses of principal components and analyses of molecular variance revealed limited genetic differentiation among isolates from different hosts, greenhouses, and years of isolate collection. In contrast, the same analyses alongside pairwise fixation indexes and an evaluation of population structure indicated significant genetic differentiation among isolates based on the number of fungicides to which they are resistant. There are two described mechanisms that confer resistance to multiple fungicides at the same time, both of which are mediated by efflux pumps. Results from a quantitative trait genome-wide association study revealed novel genomic regions associated with multifungicide resistance, including two genes that encode putative efflux pumps. An understanding of fungicide resistance patterns is essential for developing durable disease control measures. Our results highlight the importance of continued monitoring of <i>B. cinerea</i> populations, as the observed genetic differentiation linked to fungicide resistance emphasizes their ability to adapt to selection pressure.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"4075-4084"},"PeriodicalIF":2.8,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147531873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}