Pub Date : 2022-11-29DOI: 10.1080/07060661.2022.2152490
Zhang Li, Li Zhanbiao, She Xiaoman, T. Farooq, Lian Zhenggang, Y. Lin, Lan Guobing, He Zifu, Yafei Tang
Abstract Cowpea plants exhibiting virescence, phyllody and little leaf symptoms were observed in the fields of Zhanjiang City, Guangdong province of China in October 2020. Total DNA was extracted from symptomatic cowpea leaves. Using phytoplasma universal primer pairs (R16mF2/R16mR1, P1/P7) and a secA primer pair (secAfor1/secArev3), expected PCR fragments of approximately 1400, 1800 and 800 bp were amplified from all symptomatic cowpea leaves. MUSCLE analysis revealed that the representative 16S rRNA gene sequence of cowpea phyllody phytoplasma (CPP) shared 98.67% nucleotide identity with the reference strain WBDL of ‘Ca. Phytoplasma aurantifolia’ (GenBank accession number U15442); and 100% nucleotide identity with 16SrII-V phytoplasmas associated with ‘Praxelis clematidea’ phyllody (GenBank accession number KY568717); ‘Desmodium triflorum’ little leaf (GenBank accession number MT452308); and ‘Ixeris chinensis’, ‘Emilia sonchifolia’, and ‘Desmodium ovalifolium’ witches’ broom (GenBank accession number MT416114, MT420682 and MK956144, respectively). Phylogenetic analyses based on the 16S rRNA and secA gene sequences revealed that the CPP strain clustered with the 16SrII-V subgroup and 16SrII group, respectively. Virtual restriction fragment length polymorphism analysis of the 16S rRNA sequence revealed that CPP was associated with the 16SrII-V subgroup. To our knowledge, this is the first report of the16SrII-V subgroup of phytoplasmas associated with cowpea phyllody disease.
{"title":"First report of 16SrII-V phytoplasma associated with cowpea (Vigna unguiculata) phyllody in China","authors":"Zhang Li, Li Zhanbiao, She Xiaoman, T. Farooq, Lian Zhenggang, Y. Lin, Lan Guobing, He Zifu, Yafei Tang","doi":"10.1080/07060661.2022.2152490","DOIUrl":"https://doi.org/10.1080/07060661.2022.2152490","url":null,"abstract":"Abstract Cowpea plants exhibiting virescence, phyllody and little leaf symptoms were observed in the fields of Zhanjiang City, Guangdong province of China in October 2020. Total DNA was extracted from symptomatic cowpea leaves. Using phytoplasma universal primer pairs (R16mF2/R16mR1, P1/P7) and a secA primer pair (secAfor1/secArev3), expected PCR fragments of approximately 1400, 1800 and 800 bp were amplified from all symptomatic cowpea leaves. MUSCLE analysis revealed that the representative 16S rRNA gene sequence of cowpea phyllody phytoplasma (CPP) shared 98.67% nucleotide identity with the reference strain WBDL of ‘Ca. Phytoplasma aurantifolia’ (GenBank accession number U15442); and 100% nucleotide identity with 16SrII-V phytoplasmas associated with ‘Praxelis clematidea’ phyllody (GenBank accession number KY568717); ‘Desmodium triflorum’ little leaf (GenBank accession number MT452308); and ‘Ixeris chinensis’, ‘Emilia sonchifolia’, and ‘Desmodium ovalifolium’ witches’ broom (GenBank accession number MT416114, MT420682 and MK956144, respectively). Phylogenetic analyses based on the 16S rRNA and secA gene sequences revealed that the CPP strain clustered with the 16SrII-V subgroup and 16SrII group, respectively. Virtual restriction fragment length polymorphism analysis of the 16S rRNA sequence revealed that CPP was associated with the 16SrII-V subgroup. To our knowledge, this is the first report of the16SrII-V subgroup of phytoplasmas associated with cowpea phyllody disease.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"103 - 109"},"PeriodicalIF":2.0,"publicationDate":"2022-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46727218","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 : 2022-11-23DOI: 10.1080/07060661.2022.2150318
Angelica Sanchez Melo, M. T. Silva, R. P. Schwengber, Guilherme Tarini, S. M. Santana‐Gomes, Elizeu Junior da Silva, C. R. Dias-Arieira
Abstract Antagonistic and non-host plants are some of the main strategies for nematode control, but the reaction of several plant species to these parasites remains to be investigated. This study aimed to evaluate the reaction of buckwheat to Pratylenchus brachyurus and Meloidogyne javanica and to assess the effect of buckwheat aqueous extract on P. brachyurus and M. javanica mortality and M. javanica hatching. Experiments were conducted under greenhouse and laboratory conditions. Treatments consisted of buckwheat ‘IPR-92 Altar’ and soybean ‘M6410 IPRO’ inoculated with different levels of P. brachyurus or M. javanica according to each experiment. Buckwheat was found to be a non-host to P. brachyurus. The RF of M. javanica on buckwheat ranged from 1.33 to 4.11, whereas the RF on soybean was 24.00. Buckwheat shoot extracts were effective in promoting nematode mortality and reducing M. javanica hatching. These findings indicate that buckwheat has potential as a cover crop for the control of P. brachyurus, but care is needed when introducing this plant to areas infested with M. javanica.
{"title":"Response of buckwheat to Pratylenchus brachyurus and Meloidogyne javanica","authors":"Angelica Sanchez Melo, M. T. Silva, R. P. Schwengber, Guilherme Tarini, S. M. Santana‐Gomes, Elizeu Junior da Silva, C. R. Dias-Arieira","doi":"10.1080/07060661.2022.2150318","DOIUrl":"https://doi.org/10.1080/07060661.2022.2150318","url":null,"abstract":"Abstract Antagonistic and non-host plants are some of the main strategies for nematode control, but the reaction of several plant species to these parasites remains to be investigated. This study aimed to evaluate the reaction of buckwheat to Pratylenchus brachyurus and Meloidogyne javanica and to assess the effect of buckwheat aqueous extract on P. brachyurus and M. javanica mortality and M. javanica hatching. Experiments were conducted under greenhouse and laboratory conditions. Treatments consisted of buckwheat ‘IPR-92 Altar’ and soybean ‘M6410 IPRO’ inoculated with different levels of P. brachyurus or M. javanica according to each experiment. Buckwheat was found to be a non-host to P. brachyurus. The RF of M. javanica on buckwheat ranged from 1.33 to 4.11, whereas the RF on soybean was 24.00. Buckwheat shoot extracts were effective in promoting nematode mortality and reducing M. javanica hatching. These findings indicate that buckwheat has potential as a cover crop for the control of P. brachyurus, but care is needed when introducing this plant to areas infested with M. javanica.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"186 - 195"},"PeriodicalIF":2.0,"publicationDate":"2022-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41358626","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 : 2022-11-17DOI: 10.1080/07060661.2022.2147587
M. G. Dias, R. Ribeiro, Caio M. de A. Barbosa, J. D. de Jesus, M. B. Spósito
Abstract Late leaf rust (Thekopsora americana) is a disease that affects raspberry (Rubus idaeus L.), leading to a decrease in raspberry production. The adoption of precise criteria for disease quantification helps decision-making for its management. A diagrammatic scale (DS) is a useful tool for quantifying disease severity in the field. A DS was developed and validated in this study to estimate late leaf rust severity in raspberry leaves. The DS was defined with eight levels of severity (0.2, 0.4, 0.9, 2.2, 5.1, 11.5, 23.9 and 43.2%). The validation was performed by 15 untrained raters in two steps, with and without using the DS. Two approaches were used for statistical analysis: linear regression and Lin’s method. Both analyses demonstrated that the use of the DS improved the precision and accuracy of the disease estimates. The inter-rater reliability was estimated by the coefficient of determination (R2) and the intra-class correlation coefficient (ICC). Again, the use of the DS improved the reproducibility of the estimates. For the first time, a diagrammatic scale was developed and validated to evaluate late leaf rust severity in raspberry leaves.
{"title":"Diagrammatic scale for improved late leaf rust severity assessments in raspberry leaves","authors":"M. G. Dias, R. Ribeiro, Caio M. de A. Barbosa, J. D. de Jesus, M. B. Spósito","doi":"10.1080/07060661.2022.2147587","DOIUrl":"https://doi.org/10.1080/07060661.2022.2147587","url":null,"abstract":"Abstract Late leaf rust (Thekopsora americana) is a disease that affects raspberry (Rubus idaeus L.), leading to a decrease in raspberry production. The adoption of precise criteria for disease quantification helps decision-making for its management. A diagrammatic scale (DS) is a useful tool for quantifying disease severity in the field. A DS was developed and validated in this study to estimate late leaf rust severity in raspberry leaves. The DS was defined with eight levels of severity (0.2, 0.4, 0.9, 2.2, 5.1, 11.5, 23.9 and 43.2%). The validation was performed by 15 untrained raters in two steps, with and without using the DS. Two approaches were used for statistical analysis: linear regression and Lin’s method. Both analyses demonstrated that the use of the DS improved the precision and accuracy of the disease estimates. The inter-rater reliability was estimated by the coefficient of determination (R2) and the intra-class correlation coefficient (ICC). Again, the use of the DS improved the reproducibility of the estimates. For the first time, a diagrammatic scale was developed and validated to evaluate late leaf rust severity in raspberry leaves.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"140 - 147"},"PeriodicalIF":2.0,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42408281","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 : 2022-11-14DOI: 10.1080/07060661.2022.2142671
HuLei Zhang, Chunxia Wang, Shenhai Wang, Shengfeng Mao
Abstract This article reports the first known occurrence of leaf spot of Kerria japonica caused by Diaporthe pescicola in China and worldwide. Leaves of K. japonica with leaf spot symptoms were collected in September 2020 from Nanjing, Jiangsu, China. Leaf lesions were of irregular shape and sizes forming mostly in the middle of the leaves, and most of the lesions were white and hazel in colour. A fungus was isolated from diseased leaves and identified as Diaporthe pescicola based on morphological features and multigene phylogenetic analysis of the internal transcribed spacer (ITS) region, elongation factor 1-alpha (EF1-α), beta-tubulin (β-tub), histone H3 (HIS) and calmodulin (CAL) genes. Three strains of isolated fungus caused leaf spot symptoms on inoculated wounded leaves of K. japonica, which were similar to the natural symptoms observed in the field. This disease greatly reduces the ornamental value of affected plants, and identification of the pathogen is significant for the prevention and control of the disease.
{"title":"Leaf spot of Kerria japonica caused by Diaporthe pescicola in China","authors":"HuLei Zhang, Chunxia Wang, Shenhai Wang, Shengfeng Mao","doi":"10.1080/07060661.2022.2142671","DOIUrl":"https://doi.org/10.1080/07060661.2022.2142671","url":null,"abstract":"Abstract This article reports the first known occurrence of leaf spot of Kerria japonica caused by Diaporthe pescicola in China and worldwide. Leaves of K. japonica with leaf spot symptoms were collected in September 2020 from Nanjing, Jiangsu, China. Leaf lesions were of irregular shape and sizes forming mostly in the middle of the leaves, and most of the lesions were white and hazel in colour. A fungus was isolated from diseased leaves and identified as Diaporthe pescicola based on morphological features and multigene phylogenetic analysis of the internal transcribed spacer (ITS) region, elongation factor 1-alpha (EF1-α), beta-tubulin (β-tub), histone H3 (HIS) and calmodulin (CAL) genes. Three strains of isolated fungus caused leaf spot symptoms on inoculated wounded leaves of K. japonica, which were similar to the natural symptoms observed in the field. This disease greatly reduces the ornamental value of affected plants, and identification of the pathogen is significant for the prevention and control of the disease.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"118 - 127"},"PeriodicalIF":2.0,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43966090","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 : 2022-11-14DOI: 10.1080/07060661.2022.2147586
Xuanzhu Zhao, Na Wang, Z. Ji, Zong-shan Zhou, Junxiang Zhang
Abstract Monocarboxylate transporters (MCTs) play vital roles in carbon source assimilation, drug resistance and virulence. However, the underlying function of MCTs in fungal pathogenesis and development has not been investigated in detail. In this study, we identified and characterized the monocarboxylate transporter gene MCT1 of Colletotrichum gloeosporioides, which is the causal agent of Glomerella leaf spot of apple. Mct1 is localized to the mitochondria and may mediate the uptake of lactate to the cell. However, MCT1 was constitutively expressed but showed an enhanced expression level in response to the presence of the extracellular lactate. Our results indicate that Mct1 plays a role in the metabolism of lactate. More importantly, the Δmct1 mutant showed significantly poor conidiation and a defect in host infection. Taken together, our studies provide evidence for Mct1 as a mitochondrial transmembrane protein mediating conidiation, the metabolism of lactate, and the pathogenicity of C. gloeosporioides.
{"title":"MCT1 plays crucial roles in conidiation, lactate metabolism and pathogenicity in Colletotrichum gloeosporioides","authors":"Xuanzhu Zhao, Na Wang, Z. Ji, Zong-shan Zhou, Junxiang Zhang","doi":"10.1080/07060661.2022.2147586","DOIUrl":"https://doi.org/10.1080/07060661.2022.2147586","url":null,"abstract":"Abstract Monocarboxylate transporters (MCTs) play vital roles in carbon source assimilation, drug resistance and virulence. However, the underlying function of MCTs in fungal pathogenesis and development has not been investigated in detail. In this study, we identified and characterized the monocarboxylate transporter gene MCT1 of Colletotrichum gloeosporioides, which is the causal agent of Glomerella leaf spot of apple. Mct1 is localized to the mitochondria and may mediate the uptake of lactate to the cell. However, MCT1 was constitutively expressed but showed an enhanced expression level in response to the presence of the extracellular lactate. Our results indicate that Mct1 plays a role in the metabolism of lactate. More importantly, the Δmct1 mutant showed significantly poor conidiation and a defect in host infection. Taken together, our studies provide evidence for Mct1 as a mitochondrial transmembrane protein mediating conidiation, the metabolism of lactate, and the pathogenicity of C. gloeosporioides.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"176 - 185"},"PeriodicalIF":2.0,"publicationDate":"2022-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46424328","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 : 2022-11-02DOI: 10.1080/07060661.2022.2087104
M. Khalil, R. Félix-Gastélum, O. Peñuelas-Rubio, Leandris Argentel-Martínez, I. Maldonado-Mendoza
Abstract Biocontrol, an alternative to chemical control against plant pathogens, may also improve plant health and enhance fruit yield. Tomato production in open fields or greenhouses is constrained by the pathogens Fusarium oxysporum f. sp. lycopersici race 3 (Fol R3) and F. oxysporum f. sp. radicis-lycopersici (Forl). In this work, we studied the biocontrol effect of the antagonistic bacteria Acinetobacter calcoaceticus AcDB3, Bacillus thuringiensis BtMB9, B. subtilis BsTA16, and B. amyloliquefaciens BaMA26 in field trials with four tomato hybrids over two consecutive growing seasons (2019–2020 and 2020–2021). The effect of these bacteria on plant growth was also evaluated. The presence of F. oxysporum in field soil and/or infected plants was confirmed microbiologically. All four bacterial strains significantly suppressed the severity of Fusarium crown and root rot of tomato (FCRRT) and Fusarium wilt symptoms, as well as increased tomato yield under field conditions. Among the four strains, B. subtilis BsTA16 showed the highest reduction in symptoms of Fusarium wilt (68%) and FCRRT (74%). To the best of our knowledge, this is the first report of biological control agents (BCAs) exerting antagonistic activity against both FCRRT caused by Forl and Fusarium wilt caused by Fol in tomato under field conditions.
{"title":"Rhizospheric bacteria for use in preventing Fusarium wilt and crown root rot of tomato under natural field conditions","authors":"M. Khalil, R. Félix-Gastélum, O. Peñuelas-Rubio, Leandris Argentel-Martínez, I. Maldonado-Mendoza","doi":"10.1080/07060661.2022.2087104","DOIUrl":"https://doi.org/10.1080/07060661.2022.2087104","url":null,"abstract":"Abstract Biocontrol, an alternative to chemical control against plant pathogens, may also improve plant health and enhance fruit yield. Tomato production in open fields or greenhouses is constrained by the pathogens Fusarium oxysporum f. sp. lycopersici race 3 (Fol R3) and F. oxysporum f. sp. radicis-lycopersici (Forl). In this work, we studied the biocontrol effect of the antagonistic bacteria Acinetobacter calcoaceticus AcDB3, Bacillus thuringiensis BtMB9, B. subtilis BsTA16, and B. amyloliquefaciens BaMA26 in field trials with four tomato hybrids over two consecutive growing seasons (2019–2020 and 2020–2021). The effect of these bacteria on plant growth was also evaluated. The presence of F. oxysporum in field soil and/or infected plants was confirmed microbiologically. All four bacterial strains significantly suppressed the severity of Fusarium crown and root rot of tomato (FCRRT) and Fusarium wilt symptoms, as well as increased tomato yield under field conditions. Among the four strains, B. subtilis BsTA16 showed the highest reduction in symptoms of Fusarium wilt (68%) and FCRRT (74%). To the best of our knowledge, this is the first report of biological control agents (BCAs) exerting antagonistic activity against both FCRRT caused by Forl and Fusarium wilt caused by Fol in tomato under field conditions.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"44 1","pages":"836 - 848"},"PeriodicalIF":2.0,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41959585","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 : 2022-10-31DOI: 10.1080/07060661.2022.2142299
O. Choi, B. Kang, Yeyeong Lee, J. Kwon, Jinwoo Kim
Abstract Severe root rot was observed in onion seedlings growing in nursery seedbeds in Changnyeong, South Korea in September 2021. The diseased onion seedlings showed symptoms including water-soaking, browning and blight, followed by seedling collapse. Three isolates were obtained from diseased onion seedlings, and their morphological characteristics were found to be similar to previously described Pythium species. Artificial inoculation with isolates produced identical symptoms to those observed in the original infection. Based on morphological characteristics, sequencing of rRNA gene internal transcribed spacer, ribosomal large subunit gene region, and cytochrome c oxidase subunit I gene region, and pathogenicity testing, the causative agent of root rot on the onion seedlings was identified as Globisporangium irregulare (formerly Pythium irregulare). This is the first report of root rot caused by G. irregulare on onion seedlings in Korea. The results of this study suggest that root rot may pose a severe threat to onion seedling cultivation.
{"title":"First report of root rot on onion (Allium cepa) seedlings caused by Globisporangium irregulare in South Korea","authors":"O. Choi, B. Kang, Yeyeong Lee, J. Kwon, Jinwoo Kim","doi":"10.1080/07060661.2022.2142299","DOIUrl":"https://doi.org/10.1080/07060661.2022.2142299","url":null,"abstract":"Abstract Severe root rot was observed in onion seedlings growing in nursery seedbeds in Changnyeong, South Korea in September 2021. The diseased onion seedlings showed symptoms including water-soaking, browning and blight, followed by seedling collapse. Three isolates were obtained from diseased onion seedlings, and their morphological characteristics were found to be similar to previously described Pythium species. Artificial inoculation with isolates produced identical symptoms to those observed in the original infection. Based on morphological characteristics, sequencing of rRNA gene internal transcribed spacer, ribosomal large subunit gene region, and cytochrome c oxidase subunit I gene region, and pathogenicity testing, the causative agent of root rot on the onion seedlings was identified as Globisporangium irregulare (formerly Pythium irregulare). This is the first report of root rot caused by G. irregulare on onion seedlings in Korea. The results of this study suggest that root rot may pose a severe threat to onion seedling cultivation.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"110 - 117"},"PeriodicalIF":2.0,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49075517","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 : 2022-10-07DOI: 10.1080/07060661.2022.2130433
M. R. Mcdonald, S. Stricker, B. Gossen
Abstract Stemphylium leaf blight (SLB), caused by the fungal pathogen Stemphylium vesicarium, is an important disease of onion (Allium cepa). This pathogen also causes disease on a wide range of other plant species. SLB on onion is managed primarily through fungicide application. The source of primary inoculum and whether S. vesicarium can overwinter in the region were not known. Inoculation and subsequent re-isolation of the pathogen from common weed species present near onion fields demonstrated that many of these weedy species are hosts of S. vesicarium. Redroot pigweed (Amaranthus retroflexus), yellow nutsedge (Cyperus esculentus), yellow marshcress (Rorippa palustris), perennial sow thistle (Sonchus arvensis) and purslane (Portulaca oleracea) were identified as new hosts of S. vesicarium and bull thistle (Cirsium vulgare) was confirmed as a host. Sporulation on dead weed residue in spring may be a source of primary inoculum for infection of adjacent onion fields. Also, a study of pathogen survival in infected leaf pieces of onion buried in soil or left at the soil surface demonstrated that S. vesicarium can overwinter in infected onion leaf residue and produce pseudothecia and ascospores in early spring. These conclusions support existing management recommendations for the burial or removal of onion debris and managing weeds in and around onion fields.
{"title":"Weed hosts and winter survival of Stemphylium vesicarium on onion in Ontario, Canada","authors":"M. R. Mcdonald, S. Stricker, B. Gossen","doi":"10.1080/07060661.2022.2130433","DOIUrl":"https://doi.org/10.1080/07060661.2022.2130433","url":null,"abstract":"Abstract Stemphylium leaf blight (SLB), caused by the fungal pathogen Stemphylium vesicarium, is an important disease of onion (Allium cepa). This pathogen also causes disease on a wide range of other plant species. SLB on onion is managed primarily through fungicide application. The source of primary inoculum and whether S. vesicarium can overwinter in the region were not known. Inoculation and subsequent re-isolation of the pathogen from common weed species present near onion fields demonstrated that many of these weedy species are hosts of S. vesicarium. Redroot pigweed (Amaranthus retroflexus), yellow nutsedge (Cyperus esculentus), yellow marshcress (Rorippa palustris), perennial sow thistle (Sonchus arvensis) and purslane (Portulaca oleracea) were identified as new hosts of S. vesicarium and bull thistle (Cirsium vulgare) was confirmed as a host. Sporulation on dead weed residue in spring may be a source of primary inoculum for infection of adjacent onion fields. Also, a study of pathogen survival in infected leaf pieces of onion buried in soil or left at the soil surface demonstrated that S. vesicarium can overwinter in infected onion leaf residue and produce pseudothecia and ascospores in early spring. These conclusions support existing management recommendations for the burial or removal of onion debris and managing weeds in and around onion fields.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"134 - 139"},"PeriodicalIF":2.0,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45344634","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 : 2022-09-07DOI: 10.1080/07060661.2022.2122081
Saliha Afzal, N. Afshan, A. Khalid
Abstract Plants of Cotinus coggygria were observed with powdery mildew symptoms during field surveys in Abbottabad, Khyber Pakhtunkhwa (KP), Pakistan in 2020. Morpho-anatomical and molecular phylogenetic analyses were used to identify the powdery mildew species parasitizing these plants as Erysiphe verniciferae. Pathogenicity was confirmed on healthy leaves of C. coggygria in a greenhouse at 25°C with 75–80% humidity at 7–10 days after inoculation, when white powdery mildew colonies appeared. This is the first report of powdery mildew caused by E. verniciferae on C. coggygria in Pakistan.
{"title":"First report of Erysiphe verniciferae causing powdery mildew on smoke tree (Cotinus coggygria) from Pakistan","authors":"Saliha Afzal, N. Afshan, A. Khalid","doi":"10.1080/07060661.2022.2122081","DOIUrl":"https://doi.org/10.1080/07060661.2022.2122081","url":null,"abstract":"Abstract Plants of Cotinus coggygria were observed with powdery mildew symptoms during field surveys in Abbottabad, Khyber Pakhtunkhwa (KP), Pakistan in 2020. Morpho-anatomical and molecular phylogenetic analyses were used to identify the powdery mildew species parasitizing these plants as Erysiphe verniciferae. Pathogenicity was confirmed on healthy leaves of C. coggygria in a greenhouse at 25°C with 75–80% humidity at 7–10 days after inoculation, when white powdery mildew colonies appeared. This is the first report of powdery mildew caused by E. verniciferae on C. coggygria in Pakistan.","PeriodicalId":9468,"journal":{"name":"Canadian Journal of Plant Pathology","volume":"45 1","pages":"35 - 40"},"PeriodicalIF":2.0,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46895976","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 : 2022-09-07DOI: 10.1080/07060661.2022.2120913
J. Cui, S. Strelkov, R. Fredua-Agyeman, S. Hwang
Abstract Verticillium stripe, caused by Verticillium longisporum, is an emerging soilborne disease of canola (Brassica napus) in Canada. Improved inoculation protocols will facilitate study of Verticillium stripe and its management. Two inoculation techniques, a root-dip method at two inoculum concentrations and a grain inoculation method at four inoculum concentrations, were compared under greenhouse conditions with the canola cultivars ‘45H31’, ‘CS2000’ and ‘Westar’. Symptoms of Verticillium stripe appeared at early growth stages following root dip inoculation, resulting in seedling mortalities of up to 19.7%, 39.5% and 33.3% for ‘CS2000’, ‘45H31’ and ‘Westar’, respectively, at 35 days post-inoculation. Plants inoculated by the root-dip method incurred much greater mortality at the high versus low inoculum concentration. In the surviving adult plants, ‘45H31’ was moderately resistant while ‘CS2000’ was more susceptible to V. longisporum. The grain inoculation method did not cause early-stage mortality, although Verticillium stripe severity at the adult stage was significantly different between control and high inoculum concentrations for all cultivars. In addition, plant dry weight and height decreased as inoculum concentration increased. Inoculation of 1-week-old, 2-week-old and 3-week-old seedlings of ‘CS2000’ and ‘Westar’ was also compared by the root-dip method. The impact of host age at inoculation on disease development was not significant, although higher disease severity was observed at later inoculation in ‘CS2000’. The application of grain inoculum may be more suitable for large-scale screening or studies conducted under field conditions.
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