Plant disease最新文献

{"title":"Wood-boring insect galleries restructure fungal communities in declining <i>Nothofagus pumilio</i> forests of Patagonia.","authors":"Lucia Molina, Geoffrey Williams, Denita Hadziabdic, María Belén Pildain","doi":"10.1094/PDIS-03-26-0552-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-26-0552-RE","url":null,"abstract":"<p><p>Forest decline is often driven by complex interactions among biotic and abiotic factors, including insects and fungi that influence tree health and disease development. In Patagonian forests, decline of Nothofagus pumilio has been associated with wood-boring insects and wood-inhabiting fungi. However, the role of insect galleries in shaping fungal communities within living trees remains poorly understood. Here we characterized fungal communities associated with galleries produced by two wood-boring insects colonizing different woody tissues of living N. pumilio: ambrosia beetles Gnathotrupes spp., which excavate galleries in the sapwood, and the carpenter moth Chilecomadia valdiviana, which develops within the heartwood. Using long-read metabarcoding (ITS and LSU, Oxford Nanopore), we compared fungal assemblages in insect galleries and wood from non-infested trees. Distinct fungal community patterns were associated with each insect species, suggesting that differences in feeding behavior and the woody tissues colonized may influence local fungal community assembly. Galleries of Gnathotrupes were dominated by ambrosia-associated fungi, particularly Raffaelea, along with ophiostomatoid taxa such as Huntiella. In contrast, galleries of C. valdiviana contained a broader assemblage of saprotrophic fungi and yeasts commonly associated with wood decay. These results indicate that different insect feeding guilds shape fungal communities associated with N. pumilio wood and may contribute to the proliferation of opportunistic and potentially pathogenic fungi. This restructuring of fungal assemblages highlights a potential role of insect activity in processes linked to tree decline and disease development in Patagonian forests.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025696","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":"Tactical Diagnostic Strategies at Native California Ornamental Nurseries for Preventing <i>Phytophthora</i> Havocs in Wildlands.","authors":"Ruchika Kashyap, Kayleigh Lampe, Timothy D Miles, Kerri Neugebauer, Frank N Martin, Johanna Del Castillo Múnera","doi":"10.1094/PDIS-03-26-0441-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-26-0441-RE","url":null,"abstract":"<p><p>Native plant restoration efforts in California are continuously challenged by Phytophthora-induced diseases, particularly through nursery introductions, resulting in significant losses and distribution of pathogens into restoration areas. Effective diagnostic strategies can help manage Phytophthora, yet determining the most suitable method, considering specificity, sampling time, resource availability, and expertise, remains uncertain. This study compares the effectiveness of five diagnostic methods: irrigation leachate baiting, ImmunoStrip® for Phytophthora, culture-based isolations, recombinase polymerase amplification (RPA, targeting genus-specific trnM-trnP-trnM locus), and quantitative polymerase chain reaction (qPCR, targeting genus-specific atp9-nad9 locus) on artificially inoculated and on naturally infested ornamental plants. For artificially inoculated plant testing, two native California ornamentals, Frangula californica and Heteromeles arbutifolia, were inoculated with three Phytophthora species: P. cinnamomi, P. cactorum, and P. cryptogea, and sampled three times, every six weeks post-inoculation. The sampled plants, along with the non-inoculated controls, were subjected to the five detection methods for Phytophthora detection. Among the detection assays, RPA, qPCR, and irrigation leachate baiting had the highest Phytophthora detection rates, regardless of the host, sampling time, or pathogen species (P < 0.01). For naturally infested plants, molecular assays consistently detected Phytophthora from three horticultural and two native nurseries (one accredited through Accreditation to Improve Restoration (AIR) program and other in process), with a subset of samples independently validated by another laboratory. The AIR-certified nursery showed no Phytophthora and the lowest detection probability across methods. These results indicate that implementing strategic detection approaches, combined with best management practices, can improve detection and prevent Phytophthora spread to wildlands.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025770","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":"Identification and fungicide sensitivity of <i>Fusarium cugenangense</i> associated with root rot disease of <i>Polygonatum cyrtonema</i> Hua in China.","authors":"Yalun Hao, Yan Zeng, Shijie Zhou, Yiran Deng, Kaifa Guo, Xiansheng Tan, Yucai Luo, Yong Chen","doi":"10.1094/PDIS-04-26-0774-SC","DOIUrl":"https://doi.org/10.1094/PDIS-04-26-0774-SC","url":null,"abstract":"<p><p>Polygonatum cyrtonema Hua is a valuable medicinal herb widely cultivated in China, but its production has been severely threatened by root rot disease. In this study, pathogenic fungi were isolated from diseased rhizome samples collected in Huaihua City, Hunan Province, and identified through morphological characterization, multi-locus phylogenetic analysis, and pathogenicity tests fulfilling Koch's postulates. In this study, isolate HJBK 4-6 of Fusarium cugenangense was identified as a causal agent and is reported here for the first time associated with root rot on P. cyrtonema Hua in China. In vitro fungicide sensitivity assay revealed that ethylicin exhibited the strongest inhibitory activity against mycelial growth of F. cugenangense (isolate HJBK 4-6) (EC50 =0.92 μg/mL), achieving 100% inhibition at 2.5 μg/mL, followed by chlorothalonil (EC50 =2.34 μg/mL, with a maximum inhibition of approximately 78%). In contrast, pyraclostrobin and osthole showed poor efficacy, with EC50 values of 19.56 μg/mL and 18.23 μg/mL, respectively. This study provides a preliminary reference for disease diagnosis and fungicide screening, but field application recommendations will require further validation through greenhouse and field trials with a broader range of isolates.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025581","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":"Endophytic <i>Pseudomonas</i> isolates elicit genotype-dependent resistance-, tolerance-, and susceptibility-associated responses in the wheat-flag smut pathosystem.","authors":"Aili Tao, Camilo Ayra-Pardo, Tan Wang, FaHu Pang, Siliang Huang","doi":"10.1094/PDIS-04-26-0820-RE","DOIUrl":"https://doi.org/10.1094/PDIS-04-26-0820-RE","url":null,"abstract":"<p><p>Flag smut (FS), caused by Urocystis tritici, remains difficult to manage, and little is known about how endophytic bacteria influence the balance between resistance and tolerance across diverse wheat genotypes. Although endophytic bacteria are increasingly explored as sustainable disease-management tools, their effects on FS outcomes and grain yield remain poorly understood. Here, we evaluated two endophytic Pseudomonas sp. strains (8-2 and 58-1-1), originally isolated from healthy winter wheat plants, for their capacity to modify FS incidence and grain yield across 14 winter wheat varieties spanning a wide range of intrinsic resistance. Seed inoculation enhanced aboveground growth in the tested variety, but disease incidence and grain yield responses varied markedly among genotypes. In most varieties, bacterial inoculation reduced FS incidence and increased grain yield, consistent with resistance-associated outcomes. In contrast, several host-strain combinations exhibited unchanged or increased disease incidence while maintaining or improving yield, indicating tolerance-associated responses. A smaller subset showed increased disease incidence accompanied by yield loss, revealing genotype-specific susceptibility outcomes. Together, these results demonstrate that the two Pseudomonas sp. strains do not uniformly suppress FS but instead differentially shape host responses to infection in a host genotype-dependent manner, giving rise to distinct resistance-, tolerance-, and susceptibility-associated phenotypes. Recognizing these distinct response phenotypes is essential for evaluating endophytic bacteria as agents of FS management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025606","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":"Occurrence and sequence diversity of apple hammerhead viroid in major apple-producing regions of northern China.","authors":"Kaijie Li, Xudong Fan, Fang Ren, Yuxin Hao, Guojun Hu, Yafeng Dong","doi":"10.1094/PDIS-05-26-0986-RE","DOIUrl":"https://doi.org/10.1094/PDIS-05-26-0986-RE","url":null,"abstract":"<p><p>Apple hammerhead viroid (AHVd) is an emerging pathogen with a global distribution in apple-growing regions. To clarify its occurrence and distribution in northern China, long non-coding RNA (lncRNA) sequencing combined with RT-PCR was employed to screen 502 apple samples from commercial orchards in Hebei, Liaoning, Inner Mongolia, Shandong, and Shaanxi. AHVd was detected in 34.7% of samples, with infection rates ranging from 25.6% to 37.5% across the five provinces. Notably, 93.7% of AHVd-positive samples were co-infected with multiple viruses, with one extreme case harboring ten distinct pathogens. Quantitative RT-PCR revealed that AHVd accumulation was significantly higher in branch phloem than in leaves or fruit peels. Phylogenetic analysis demonstrated that Chinese AHVd isolates formed a distinct monophyletic group (Group II), although varieties clustered with Italian, Canadian, and German lineages. Sequence analysis identified nucleotide variations exclusively localized within stem-loop I, including a 5-nt deletion and a 10-nt insertion, without disrupting the conserved rod-shaped and highly branched secondary structure. These findings elucidate the epidemiology, genetic diversity, and tissue-specific distribution of AHVd in northern China, providing a foundation for improved diagnostic protocols and management strategies.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025605","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":"Effects of Climate and Cropping Systems on Perithecial Production by <i>Fusarium asiaticum</i> and <i>F. graminearum</i> sensu stricto.","authors":"Yan Yan Ru, Shuna Xie, Jing Sun, Bao Ye Li, Xin Tao Wang, Bing Li, Hao Zhang, Jun Jie Hao","doi":"10.1094/PDIS-04-26-0688-RE","DOIUrl":"https://doi.org/10.1094/PDIS-04-26-0688-RE","url":null,"abstract":"<p><p>The two dominant Fusarium head blight (FHB) pathogens in China (3-acetyl-deoxynivalenol chemotype of <i>Fusarium asiaticum</i> [<i>F. asiaticum</i> 3ADON] and 15-acetyl-deoxynivalenol chemotype of <i>F. graminearum</i> sensu stricto [<i>F. graminearum</i> 15ADON]) display distinct geographic distributions with different cropping systems. The effects of climate and cropping systems on perithecial production by these two pathogens were examined at four sites annually over three years (five locations in total). Within each year, perithecial production by <i>F. asiaticum</i> 3ADON and <i>F. graminearum</i> 15ADON on inoculated stalks (rice and maize in 2017; maize only in 2020 and 2023) decreased from south (Yancheng in 2017; Xinyang in 2020 and 2023) to north (Zhumadian, Xuchang, and Xinxiang in all three years), with significant differences among sites (P < 0.01). Production on maize stalks was higher than on rice stalks at the same site in 2017, the only year when both stalk types were evaluated. On maize stalks, no significant differences were observed in 2017 or 2023 (P > 0.05), whereas in 2020 production was markedly lower, and differed significantly between species (P < 0.01). Correlation and stepwise regression analyses identified average daily temperature from stalk placement to investigation (TEM) and average daily relative humidity in mid-March (RH3m) as the key factors affecting perithecial production on inoculated maize stalks. Pathogen composition on naturally diseased wheat spikes and crop residues revealed that <i>F. asiaticum</i> 3ADON dominated (≥83.3%) in wheat-rice rotation fields south of the Huai River, whereas <i>F. graminearum</i> 15ADON was prevalent (≥71.4%) in wheat-maize rotation fields north of the Huai River. Inoculated stalks displayed no consistent differences in perithecial production between the two species. This is inconsistent with their natural distribution patterns. Therefore, under equivalent initial colonization levels, temperature, relative humidity, and precipitation from mid-January (stalk placement) to mid-April (wheat flowering) do not drive the geographic distributions of <i>F. asiaticum</i> 3ADON and <i>F. graminearum</i> 15ADON by influencing perithecial production on crop residues.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025648","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":"Effect of nucleic acid extraction methodology and PCR chemistry on the detection of '<i>Candidatus</i> Phytoplasma pruni' in sweet cherry.","authors":"Sarah Cowell, Scott Harper","doi":"10.1094/PDIS-05-26-0875-SC","DOIUrl":"https://doi.org/10.1094/PDIS-05-26-0875-SC","url":null,"abstract":"<p><p>Early and accurate detection of 'Candidatus Phytoplasma pruni' is essential for the control of X-disease in Prunus species, but this is made difficult by pathogen biology and the ability to consistently recover nucleic acids, both of which increase the likelihood of false negatives. Here we examined the latter, using high- and low-titer infected sweet cherry (P. avium) samples to compare three tissue disruption methods, four nucleic acid extraction chemistries, and four PCR chemistries. Results showed that method selection had minimal impact on high-titer samples but significantly affected low-titer detection. Bead-beating disruption consistently outperformed rotary and manual grinding, yielding lower Cq values and more reliable amplification. Among extraction methods, CTAB-based protocols provided the highest nucleic acid recovery and detection sensitivity, particularly when paired with bead beating. Column- and magnetic bead-based kits performed less consistently, especially with low-titer samples, where false negatives were frequent. PCR chemistry also influenced results, although RT-qPCR did not significantly improve sensitivity over qPCR. Importantly, commonly used host internal controls failed to reliably indicate pathogen detection success, as high-abundance targets masked poor extraction efficiency. Cumulatively these data suggest the need for optimizing diagnostic protocols to ensure capture of low-concentration pathogens to avoid false negatives.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025410","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":"Genetic dissection of seedling resistance to septoria nodorum blotch resistance in a nested association mapping panel derived from synthetic hexaploid wheat lines and bread wheat.","authors":"Anil Karmacharya, Dhondup Lhamo, Han-Chang Chang, Jason Fiedler, Timothy L Friesen, Justin D Faris, Shengming Yang, Yong Q Gu, Steven S Xu, Zhaohui Liu, Xiaofei Zhang","doi":"10.1094/PDIS-01-26-0156-RE","DOIUrl":"https://doi.org/10.1094/PDIS-01-26-0156-RE","url":null,"abstract":"<p><p>Septoria nodorum blotch (SNB), caused by the necrotrophic fungal pathogen Parastagonospora nodorum, is a major foliar disease of wheat (Triticum aestivum) that significantly reduces grain yield and quality. In this study, we evaluated a modified nested association mapping (NAM) population for SNB resistance. This population consisted of 276 BC1F8 progenies derived from crosses between four synthetic hexaploid wheat (SHW) and ten hard red spring wheat (HRSW) varieties/lines. We screened the population using two P. nodorum isolates (Sn4 and Sn2000) and three necrotrophic effectors (SnToxA, SnTox1, and SnTox3). Genome-wide association studies using the 90K SNP markers identified 32 significant marker-trait associations (MTAs) across nine chromosomes, including nine markers associated with isolate responses and 23 with effector sensitivity. While several markers co-localized with known genes such as Tsn1 (5BL), Snn2 (2DS), Snn3 (5BS), and Snn7 (2DL), we also identified novel loci that expand our understanding of SNB resistance. Of the nine isolate-associated MTAs, the resistance alleles were contributed by different parents: four came from SHW, one from HRSW, and four from both parental types. Nine progeny lines exhibited resistance to both isolates and insensitivity to all tested effectors, indicating broad-spectrum and effective resistance. The SHW lines SW91 and SW93, as well as HRSW cultivars 'Bolles' and 'Linkert', and their progenies consistently showed increased resistance compared to other backgrounds. These lines, carrying novel SNB resistance loci derived from cultivated emmer and Aegilops tauschii, provide valuable germplasm for improving SNB resistance in wheat breeding programs.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025653","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":"Physiological and transcriptomic analyses reveal the antifungal activity of <i>Simplicillium lanosoniveum</i> filtrate against wheat crown rot pathogen <i>Fusarium pseudograminearum</i>.","authors":"Zhenjie Hu, Yihao Cai, Rongrong Zhai, Youfei Zhao, Yawei Fan, Bo Min, Chenhao Sun, Xingli Zhao","doi":"10.1094/PDIS-04-26-0829-RE","DOIUrl":"https://doi.org/10.1094/PDIS-04-26-0829-RE","url":null,"abstract":"<p><p>Fusarium pseudograminearum (Fp), the predominant phytopathogen responsible for wheat crown rot, severely impairs wheat growth and yield, posing a persistent threat to global wheat production. This study evaluated the biocontrol potential of the fermentation filtrate from the endophytic fungus Simplicillium lanosoniveum FSL-376 against Fp. In vitro, the filtrate exhibited potent antifungal activity, significantly inhibiting mycelial growth, and causing severe morphological abnormalities in both hyphae and spores at low concentrations. Mechanistic investigations revealed that the antifungal action was achieved by disrupting fungal cell membrane integrity [evidenced by increased electrolyte conductivity and malondialdehyde (MDA) accumulation], triggering intense oxidative stress via suppressing the activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and disrupting energy metabolism through the inhibition of hexokinase (HK) and succinate dehydrogenase (SDH) activities. Transcriptomic analysis further revealed multi-target inhibition, characterized by the downregulation of genes involved in transmembrane transport, antioxidant defense, and oxidative phosphorylation. In pot experiments, seed treatment with the FSL-376 filtrate significantly alleviated Fp-induced growth inhibition, restored antioxidant enzyme activities and chlorophyll content in wheat seedlings, and improved root morphology. Notably, the FSL-376 filtrate exhibited no phytotoxicity to wheat seedlings and showed no growth-promoting effect under pathogen-free conditions, indicating its biosafety and pathogen-specific biocontrol efficacy. This study demonstrates that S. lanosoniveum FSL-376 serves as a promising and reliable biocontrol resource for wheat crown rot management, which functions via dual mechanisms of direct antifungal inhibition and enhancement of host plant stress tolerance.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025735","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":"Detection of SdhB mutations in <i>Botrytis cinerea</i> isolates from strawberry using a High-Resolution Melting (HRM) assay.","authors":"Adrian Israel Zuniga, Nan-Yi Wang, Carolina Suguinoshita Rebello, Mayara Bolognesi, Bruna Balen Forcelini, Natalia A Peres","doi":"10.1094/PDIS-03-26-0492-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-26-0492-RE","url":null,"abstract":"<p><p><i>Botrytis cinerea</i>, the causal agent of Botrytis fruit rot (BFR), is one of the most destructive pathogens of strawberry. In Florida, BFR management relies heavily on succinate dehydrogenase inhibitor (SDHI) fungicides; however, resistance associated with mutations in the SdhB subunit has increasingly been reported. This study developed and validated a high-resolution melting (HRM) assay for rapid detection of SdhB mutations directly from <i>B. cinerea</i> spores, and evaluated resistance frequencies to fluopyram, isofetamid, and pydiflumetofen across Florida strawberry fields. Two HRM primer sets successfully differentiated SdhB mutations H272R or Y, N230I, and P225F based on distinct melting profiles. The assay detected mutations from spore concentrations as low as 10⁵ spores/ml, without requiring DNA extraction or post-PCR processing. Sanger sequencing subsequently confirmed complete agreement with HRM genotyping results. Among 133 field isolates collected from 2017 to 2022, N230I and P225F were the most frequent mutations, correlating with moderate to high resistance to fluopyram and isofetamid. Resistance monitoring of 1,496 isolates over eight strawberry seasons revealed increasing resistance to fluopyram (44.9-99%) and isofetamid (≤57%), whereas pydiflumetofen resistance remained below 15%. Sequencing of SdhC and SdhD subunits revealed minimal variability and no new target-site mutations. Detached fruit assays confirmed reduced efficacy of isofetamid against isolates harboring N230I. The HRM assay developed here provides a rapid, accurate, and cost-effective tool for detecting and monitoring SDHI resistance in <i>B. cinerea</i> populations in strawberry production systems.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149025384","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}