Pub Date : 2023-04-25DOI: 10.1080/07060661.2023.2202488
Potato ( Solanum tuberosum L.) is an annual tetraploid and heterozygous plant that belongs to the family Solanaceae. This horticultural crop is a popular vegetable and the fourth economically and socially important food crop worldwide. Potato encounters different biotic stresses caused by fungi, bacteria, mycoplasma
{"title":"Southwestern Ontario regional meeting, 2022 / Réunion régionale du-oust de l’Ontario, 2022","authors":"","doi":"10.1080/07060661.2023.2202488","DOIUrl":"https://doi.org/10.1080/07060661.2023.2202488","url":null,"abstract":"Potato ( Solanum tuberosum L.) is an annual tetraploid and heterozygous plant that belongs to the family Solanaceae. This horticultural crop is a popular vegetable and the fourth economically and socially important food crop worldwide. Potato encounters different biotic stresses caused by fungi, bacteria, mycoplasma","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135114756","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}
Pub Date : 2023-04-12DOI: 10.1080/07060661.2023.2195843
Samir Galvis-López, Mauricio Salazar-Yepes, Juan Morales-Osorio
In the arboretum of Universidad Nacional de Colombia sede Medellín, Cassia fistula (Golden Shower Tree) and Leucaena leucocephala (Leucaena) exhibited early defoliation. Erysiphe quercicola and Telimena canafistulae, associated with powdery mildew and tar spot, respectively, on C. fistula, were identified using morphological and molecular techniques, both representing new records of fungi for Colombia. Similarly, Phyllactinia leucaenae was proposed as a new combination for Ovulariopsis leucaenae and was associated with powdery mildew on L. leucocephala, which to the best of our knowledge is another new record for Colombia.
在哥伦比亚国立大学(universsidad Nacional de Colombia)植物园内(sede Medellín)， Cassia (Golden Shower Tree)和Leucaena Leucaena (Leucaena)出现了早期落叶。利用形态学和分子技术鉴定了C.瘘管上分别与白粉病和油斑有关的Erysiphe quercicola和Telimena canafistulae，两者都是哥伦比亚真菌的新记录。同样地，白毛毛菌(Phyllactinia leucaenae)被提出为白毛毛菌(Ovulariopsis leucaenae)的新组合，并与L. leucocephala上的白粉病有关联，据我们所知，这是哥伦比亚的另一个新记录。
{"title":"New records of parasitic fungi on <i>Cassia fistula</i> and <i>Leucaena leucocephala</i> (Fabaceae) in Colombia","authors":"Samir Galvis-López, Mauricio Salazar-Yepes, Juan Morales-Osorio","doi":"10.1080/07060661.2023.2195843","DOIUrl":"https://doi.org/10.1080/07060661.2023.2195843","url":null,"abstract":"In the arboretum of Universidad Nacional de Colombia sede Medellín, Cassia fistula (Golden Shower Tree) and Leucaena leucocephala (Leucaena) exhibited early defoliation. Erysiphe quercicola and Telimena canafistulae, associated with powdery mildew and tar spot, respectively, on C. fistula, were identified using morphological and molecular techniques, both representing new records of fungi for Colombia. Similarly, Phyllactinia leucaenae was proposed as a new combination for Ovulariopsis leucaenae and was associated with powdery mildew on L. leucocephala, which to the best of our knowledge is another new record for Colombia.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135289104","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}
Pub Date : 2023-04-06DOI: 10.1080/07060661.2023.2195297
{"title":"In memoriam / En mémoire: Stephen Reynolds February 17 1993 – September 21 2022","authors":"","doi":"10.1080/07060661.2023.2195297","DOIUrl":"https://doi.org/10.1080/07060661.2023.2195297","url":null,"abstract":"","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49170874","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}
Pub Date : 2023-04-03DOI: 10.1080/07060661.2023.2198489
J. A. Aldana, H. Kope, B. Hawkins
Abstract The wood properties of western redcedar (Thuja plicata) (WRC) are revered in traditional practices by Pacific Coast First Nations and valued for speciality commercial purposes. In the near future, WRC harvesting will shift to second growth from old-growth, however, its cultural significance will persist, and the superior physical and chemical properties of the wood mean that it will remain in high demand. Investigating and understanding the adaptations of the species to environmental and pathogen stress in the face of changing climates can assure a sustainable supply of WRC. Of the pathogens affecting WRC, cedar leaf blight (Didymascella thujina) (CLB) is the most severe. This foliar disease infects the leaflets of seedlings and mature trees, causing a loss of photosynthetic area resulting in decreased growth or mortality. The disease is more severe on nursery seedlings than mature trees. Future projected climates in WRC’s native range are expected to increase the prevalence of, and damage from CLB. This review summarizes the state of knowledge and emphasizes recent advances in the understanding of the Thuja – Didymascella pathosystem.
{"title":"Western redcedar — natural history and pathosystems, with emphasis on cedar leaf blight","authors":"J. A. Aldana, H. Kope, B. Hawkins","doi":"10.1080/07060661.2023.2198489","DOIUrl":"https://doi.org/10.1080/07060661.2023.2198489","url":null,"abstract":"Abstract The wood properties of western redcedar (Thuja plicata) (WRC) are revered in traditional practices by Pacific Coast First Nations and valued for speciality commercial purposes. In the near future, WRC harvesting will shift to second growth from old-growth, however, its cultural significance will persist, and the superior physical and chemical properties of the wood mean that it will remain in high demand. Investigating and understanding the adaptations of the species to environmental and pathogen stress in the face of changing climates can assure a sustainable supply of WRC. Of the pathogens affecting WRC, cedar leaf blight (Didymascella thujina) (CLB) is the most severe. This foliar disease infects the leaflets of seedlings and mature trees, causing a loss of photosynthetic area resulting in decreased growth or mortality. The disease is more severe on nursery seedlings than mature trees. Future projected climates in WRC’s native range are expected to increase the prevalence of, and damage from CLB. This review summarizes the state of knowledge and emphasizes recent advances in the understanding of the Thuja – Didymascella pathosystem.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47705719","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}
Pub Date : 2023-03-29DOI: 10.1080/07060661.2023.2195825
Mary Carmen Pacheco-Esteva, Delia Soto‐Castro, A. Vásquez-López, J. M. Tovar‐Pedraza
Abstract Papaya fruit cv. Maradol showing typical symptoms of anthracnose were observed in a commercial orchard located in the municipality of Pinotepa Nacional at the coastal region of Oaxaca, Mexico in September 2020. The incidence rate of anthracnose reached 60%. The symptoms consisted of sunken, water-soaked lesions with salmon-coloured conidia masses on the surface of papaya fruit. The aim of this study was to identify the causal agent of papaya anthracnose based on the phylogenetic analysis of four concatenated datasets. The isolate exhibited sparse white to greyish aerial mycelium and clearly shaped concentric rings with exudate of orange conidia on potato dextrose agar. The fungus was identified as Colletotrichum brevisporum using sequence data of the internal transcribed spacer (ITS) region, and part of the actin (act), glyceraldehyde-3-phosphate dehydrogenase (gapdh), and chitin synthase (chs-1) genes. The fungus isolated from diseased fruit produced lesions on wounded fruit and unwounded fruit. The pathogen was re-isolated from lesions on inoculated fruit to fulfill Koch’s postulates. To our knowledge, this is the first report of C. brevisporum causing anthracnose disease on papaya fruit in Mexico.
{"title":"Colletotrichum brevisporum causing anthracnose of papaya (Carica papaya L.) in Mexico","authors":"Mary Carmen Pacheco-Esteva, Delia Soto‐Castro, A. Vásquez-López, J. M. Tovar‐Pedraza","doi":"10.1080/07060661.2023.2195825","DOIUrl":"https://doi.org/10.1080/07060661.2023.2195825","url":null,"abstract":"Abstract Papaya fruit cv. Maradol showing typical symptoms of anthracnose were observed in a commercial orchard located in the municipality of Pinotepa Nacional at the coastal region of Oaxaca, Mexico in September 2020. The incidence rate of anthracnose reached 60%. The symptoms consisted of sunken, water-soaked lesions with salmon-coloured conidia masses on the surface of papaya fruit. The aim of this study was to identify the causal agent of papaya anthracnose based on the phylogenetic analysis of four concatenated datasets. The isolate exhibited sparse white to greyish aerial mycelium and clearly shaped concentric rings with exudate of orange conidia on potato dextrose agar. The fungus was identified as Colletotrichum brevisporum using sequence data of the internal transcribed spacer (ITS) region, and part of the actin (act), glyceraldehyde-3-phosphate dehydrogenase (gapdh), and chitin synthase (chs-1) genes. The fungus isolated from diseased fruit produced lesions on wounded fruit and unwounded fruit. The pathogen was re-isolated from lesions on inoculated fruit to fulfill Koch’s postulates. To our knowledge, this is the first report of C. brevisporum causing anthracnose disease on papaya fruit in Mexico.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41373672","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}
Pub Date : 2023-03-28DOI: 10.1080/07060661.2023.2196518
S. Westerveld, R. Riddle, F. Shi
Abstract Ginseng replant disease (GRD) prevents the successful production of a second ginseng crop on the same ground even decades after the first crop. A study was initiated in 2013 to compare the efficacy of fumigants and biofumigants at two sites: (1) a replant garden planted to ginseng one year after a crop had been harvested, and (2) a non-replant site in which ginseng had never been grown. Treatments included chloropicrin and metam-sodium fumigants covered in totally impermeable film (TIF), un-tarped metam-sodium, modified mustard seed meal (MSM), and a mustard-capsaicin product (MC), and both a tarped and un-tarped control. Treatments were applied in June and July 2013 and ginseng seeded in August 2013. Plant stand was assessed monthly throughout the trial beginning after germination in spring 2014, and yield and quality were assessed at harvest in 2016 (replant site) and 2017 (non-replant site). At the replant site, plant stand declined rapidly in the un-tarped control, MSM, and MC treatments in the seedling year with no roots surviving to harvest. Although all plots had some disease at harvest, chloropicrin, metam-sodium, and the tarped control significantly improved yield. Disease pressures were low at the non-replant site and there were no consistent differences among treatments. Using Koch’s postulates, the cause of the rot in the replanted plot was confirmed to be Ilyonectria mors-panacis, although other factors are likely involved in the disease. Plant parasitic nematodes were not present in the replant site suggesting they may not be important factors in replant disease severity.
{"title":"Efficacy of fumigants and biofumigants for the control of replant disease of American ginseng (Panax quinquefolius)","authors":"S. Westerveld, R. Riddle, F. Shi","doi":"10.1080/07060661.2023.2196518","DOIUrl":"https://doi.org/10.1080/07060661.2023.2196518","url":null,"abstract":"Abstract Ginseng replant disease (GRD) prevents the successful production of a second ginseng crop on the same ground even decades after the first crop. A study was initiated in 2013 to compare the efficacy of fumigants and biofumigants at two sites: (1) a replant garden planted to ginseng one year after a crop had been harvested, and (2) a non-replant site in which ginseng had never been grown. Treatments included chloropicrin and metam-sodium fumigants covered in totally impermeable film (TIF), un-tarped metam-sodium, modified mustard seed meal (MSM), and a mustard-capsaicin product (MC), and both a tarped and un-tarped control. Treatments were applied in June and July 2013 and ginseng seeded in August 2013. Plant stand was assessed monthly throughout the trial beginning after germination in spring 2014, and yield and quality were assessed at harvest in 2016 (replant site) and 2017 (non-replant site). At the replant site, plant stand declined rapidly in the un-tarped control, MSM, and MC treatments in the seedling year with no roots surviving to harvest. Although all plots had some disease at harvest, chloropicrin, metam-sodium, and the tarped control significantly improved yield. Disease pressures were low at the non-replant site and there were no consistent differences among treatments. Using Koch’s postulates, the cause of the rot in the replanted plot was confirmed to be Ilyonectria mors-panacis, although other factors are likely involved in the disease. Plant parasitic nematodes were not present in the replant site suggesting they may not be important factors in replant disease severity.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41924326","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}
Pub Date : 2023-03-15DOI: 10.1080/07060661.2023.2190165
M. Cruickshank
Abstract Roots represent a third of terrestrial biomass. After logging, fungal pathogens use stump roots as a food base to survive and this may result in negative impact on aboveground plant production. Mycelial spread determines the fungal volume in the stump, which in turn dictates inoculum potential and spread distance; hence, it is a key disease factor. The current study focuses on the spread and confrontation of two sympatric species of Armillaria with differing virulence. Living cut blocks of Douglas-fir stem were inoculated at opposite ends with a virulent Armillaria ostoyae isolate, or four A. sinapina isolates with low virulence from two biogeoclimatic zones. The inoculum blocks were buried in moist sand, and then the surface area and volume occupied by each was determined. The drier zone A. sinapina isolates colonized 80% of the block surface areas, while the moister zone isolates were about equal with A. ostoyae (42% colonized). Additionally, inoculum blocks of each species were buried against a root and root collar of two living trees, the trees were cut, and the stumps became colonized. One stump had greater A. ostoyae colonization over A. sinapina by 12%, and the other larger stump by 74% because of thicker root collar bark that hindered A. sinapina. All interspecific encounters produced a stalemate. Increased growth potential of A. sinapina in drier zones might enable root colonization before drying. Southern Canada is forecast to become drier and warmer, favouring A. ostoyae over A. sinapina in the currently more productive areas, with an increasing negative impact on aboveground productivity.
{"title":"Colonization and confrontation of four Armillaria sinapina isolates to Armillaria ostoyae within inoculated wood blocks and stumps","authors":"M. Cruickshank","doi":"10.1080/07060661.2023.2190165","DOIUrl":"https://doi.org/10.1080/07060661.2023.2190165","url":null,"abstract":"Abstract Roots represent a third of terrestrial biomass. After logging, fungal pathogens use stump roots as a food base to survive and this may result in negative impact on aboveground plant production. Mycelial spread determines the fungal volume in the stump, which in turn dictates inoculum potential and spread distance; hence, it is a key disease factor. The current study focuses on the spread and confrontation of two sympatric species of Armillaria with differing virulence. Living cut blocks of Douglas-fir stem were inoculated at opposite ends with a virulent Armillaria ostoyae isolate, or four A. sinapina isolates with low virulence from two biogeoclimatic zones. The inoculum blocks were buried in moist sand, and then the surface area and volume occupied by each was determined. The drier zone A. sinapina isolates colonized 80% of the block surface areas, while the moister zone isolates were about equal with A. ostoyae (42% colonized). Additionally, inoculum blocks of each species were buried against a root and root collar of two living trees, the trees were cut, and the stumps became colonized. One stump had greater A. ostoyae colonization over A. sinapina by 12%, and the other larger stump by 74% because of thicker root collar bark that hindered A. sinapina. All interspecific encounters produced a stalemate. Increased growth potential of A. sinapina in drier zones might enable root colonization before drying. Southern Canada is forecast to become drier and warmer, favouring A. ostoyae over A. sinapina in the currently more productive areas, with an increasing negative impact on aboveground productivity.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42558127","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}
Pub Date : 2023-02-27DOI: 10.1080/07060661.2023.2185291
A. Zboralski, A. Biessy, M. Filion
Abstract Numerous plant-beneficial Pseudomonas strains have been isolated and characterized for their ability to control plant pathogens and the diseases they cause under controlled conditions. Only a few have, however, demonstrated consistent field efficacy. Better exploitation of genomic information and consideration of the ecological competence of strains of interest could help overcome this major inconsistency. In this minireview, we will discuss these two important aspects that we consider crucial in the development of effective Pseudomonas biocontrol inoculants. We will first explore how the increasing availability of genomic data can empower researchers who study Pseudomonas-mediated biocontrol to better understand the mechanisms at play. We will then discuss the key roles played by ecological competence in the successful development of Pseudomonas-based biocontrol inoculants and how researchers can better select ecologically competent strains. A better understanding of these factors could help accelerate the development of effective Pseudomonas inoculants and prevent wasting precious time and resources performing field experiments with strains that have little chance to succeed.
{"title":"Genome exploration and ecological competence are key to developing effective Pseudomonas-based biocontrol inoculants","authors":"A. Zboralski, A. Biessy, M. Filion","doi":"10.1080/07060661.2023.2185291","DOIUrl":"https://doi.org/10.1080/07060661.2023.2185291","url":null,"abstract":"Abstract Numerous plant-beneficial Pseudomonas strains have been isolated and characterized for their ability to control plant pathogens and the diseases they cause under controlled conditions. Only a few have, however, demonstrated consistent field efficacy. Better exploitation of genomic information and consideration of the ecological competence of strains of interest could help overcome this major inconsistency. In this minireview, we will discuss these two important aspects that we consider crucial in the development of effective Pseudomonas biocontrol inoculants. We will first explore how the increasing availability of genomic data can empower researchers who study Pseudomonas-mediated biocontrol to better understand the mechanisms at play. We will then discuss the key roles played by ecological competence in the successful development of Pseudomonas-based biocontrol inoculants and how researchers can better select ecologically competent strains. A better understanding of these factors could help accelerate the development of effective Pseudomonas inoculants and prevent wasting precious time and resources performing field experiments with strains that have little chance to succeed.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47460808","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}
Pub Date : 2023-02-23DOI: 10.1080/07060661.2023.2175912
Sanjib Sapkota, R. Burlakoti, Z. Punja
Abstract Raspberry root rot and wilting complex (RRWC), primarily caused by Phytophthora rubi, is the most important disease for raspberry producers in Canada. There is currently little to no information on phenotypic diversity or sensitivity to metalaxyl-m of P. rubi isolates affecting raspberries in Canada. This study was conducted to understand the diversity in virulence and sensitivity to metalaxyl-m of P. rubi populations collected from diverse raspberry cultivars, fields, and locations during 2018–2020. All isolates of P. rubi (n = 24) were pathogenic on ‘Chemainus’ raspberry and showed significant variation (P < 0.05) in days to first foliar symptom development (DFSD) and progress in wilting index, as indicated by relative areas under disease progress curves (rAUDPC). Principal component analyses identified that root rot index, rAUDPC, DFSD, and percentage reduction in root length and weight were important variables in assessing pathogen virulence. Metalaxyl-m sensitivity was assessed using a radial growth assay and effective concentrations that inhibited 50% of mycelial growth (EC50) were determined for 44 isolates. The EC50 values ranged from 0.035–4.71 µg mL−1 with a mean value of 0.793 µg mL−1. About 61% of the isolates were very sensitive (EC50 values <0.20 µg mL−1), 25% of isolates were considered sensitive (EC50 values of 0.21–1.18 µg mL−1), and 14% of isolates showed reduced sensitivity to metalaxyl-m (EC50 value range of 1.19–4.71 µg mL−1). Knowledge of pathogen phenotypic diversity will be useful for raspberry breeders in screening genotypes against RRWC and the results of the fungicide sensitivity study will be useful in developing management strategies for RRWC.
摘要覆盆子根腐病(RRWC)是加拿大覆盆子生产中最重要的病害，主要由疫霉(Phytophthora rubi)引起。目前几乎没有关于影响加拿大覆盆子的红斑假单胞菌分离株的表型多样性或对甲酰基-m的敏感性的信息。本研究旨在了解2018-2020年不同覆盆子品种、不同田地和不同地点的覆盆子P. rubi种群的毒力多样性和对甲氨苄的敏感性。所有分离株(n = 24)对‘Chemainus’覆盆子均具有致病性，并且在发病进展曲线(rAUDPC)下的相对面积上，对第一叶症状发展(DFSD)的天数和萎蔫指数的进展有显著差异(P < 0.05)。主成分分析表明，根腐病指数、rAUDPC、DFSD以及根长和根重减少百分比是评估病原菌毒力的重要变量。采用径向生长试验评估了甲氨酰基-m的敏感性，并测定了44株菌株抑制50%菌丝生长的有效浓度(EC50)。EC50值为0.035 ~ 4.71µg mL−1，平均值为0.793µg mL−1。约61%的分离株对甲酰基-m非常敏感(EC50值<0.20µg mL - 1)， 25%的分离株对甲酰基-m敏感(EC50值为0.21 ~ 1.18µg mL - 1)， 14%的分离株对甲酰基-m敏感性降低(EC50值范围为1.19 ~ 4.71µg mL - 1)。了解病原菌表型多样性将有助于树莓育种者筛选抗RRWC的基因型，而杀菌剂敏感性研究的结果将有助于制定RRWC的管理策略。
{"title":"Diversity in virulence and metalaxyl-m sensitivity of Phytophthora rubi isolates has implications for raspberry root rot and wilting complex management","authors":"Sanjib Sapkota, R. Burlakoti, Z. Punja","doi":"10.1080/07060661.2023.2175912","DOIUrl":"https://doi.org/10.1080/07060661.2023.2175912","url":null,"abstract":"Abstract Raspberry root rot and wilting complex (RRWC), primarily caused by Phytophthora rubi, is the most important disease for raspberry producers in Canada. There is currently little to no information on phenotypic diversity or sensitivity to metalaxyl-m of P. rubi isolates affecting raspberries in Canada. This study was conducted to understand the diversity in virulence and sensitivity to metalaxyl-m of P. rubi populations collected from diverse raspberry cultivars, fields, and locations during 2018–2020. All isolates of P. rubi (n = 24) were pathogenic on ‘Chemainus’ raspberry and showed significant variation (P < 0.05) in days to first foliar symptom development (DFSD) and progress in wilting index, as indicated by relative areas under disease progress curves (rAUDPC). Principal component analyses identified that root rot index, rAUDPC, DFSD, and percentage reduction in root length and weight were important variables in assessing pathogen virulence. Metalaxyl-m sensitivity was assessed using a radial growth assay and effective concentrations that inhibited 50% of mycelial growth (EC50) were determined for 44 isolates. The EC50 values ranged from 0.035–4.71 µg mL−1 with a mean value of 0.793 µg mL−1. About 61% of the isolates were very sensitive (EC50 values <0.20 µg mL−1), 25% of isolates were considered sensitive (EC50 values of 0.21–1.18 µg mL−1), and 14% of isolates showed reduced sensitivity to metalaxyl-m (EC50 value range of 1.19–4.71 µg mL−1). Knowledge of pathogen phenotypic diversity will be useful for raspberry breeders in screening genotypes against RRWC and the results of the fungicide sensitivity study will be useful in developing management strategies for RRWC.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44546269","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}
Pub Date : 2023-02-21DOI: 10.1080/07060661.2023.2181871
Yu Liu, S. Liang, Qiuyu Yao, Haixia Ding, Zhong Li
Abstract Bletilla striata is a traditional Chinese medicine plant. Guizhou Province is the largest producer of B. striata, with the biggest cultivation area and highest yield in China. Anthracnose is the main disease affecting the crop. In July 2021, an anthracnose outbreak occurred in Shibing County, Guizhou Province, seriously affecting the yield and quality of B. striata. Thirty samples of B. striata anthracnose were collected from Shuangjing, Niudachang, and Yangliutang towns in three main planting areas of Shibing County to clarify the causal agent of B. striata anthracnose. Fifty anthracnose strains were isolated by tissue isolation and single-conidium culture. Through morphological observation and multigene phylogenetic analysis of the internal transcribed spacer, actin, beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase and chitin synthase genes, the isolated strains were identified as Colletotrichum spaethianum. The infection process of C. spaethianum on B. striata leaves was observed by cell tissue staining. The results showed that at 25°C, the conidia of C. spaethianum on B. striata leaves began to germinate after 3 h, and the peak period of conidia germination was 8 h. Appressoria formation peaked after 24 h. During 48–72 h, the hyphae randomly expanded horizontally and vertically on the host surface, gradually forming a reticular distribution. This study is the first report of C. spaethianum causing anthracnose in B. striata. Our study clarifies the infection and development process of C. spaethianum on B. striata leaves, thus providing a theoretical basis for further study on the monitoring of B. striata anthracnose.
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