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Zhao L, Sun W, Zhang L, Yin Y, Xie Y, Zhang Y. Heart Rot Disease of Walnut Caused by Nothophoma juglandis sp. nov. and Its Endophytic Biocontrol Agent. PLANT DISEASE 2024; 108:746-756. [PMID: 37787687 DOI: 10.1094/pdis-11-22-2660-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
English walnut (Juglans regia L.) is an economically important hardwood tree species cultivated worldwide. Walnut heart rot disease leading to heartwood decay of trees has been frequently observed in a number of plantations in China. To identify the causal agent, 29 diseased stem samples were collected from walnut plantations in Beijing, and 54 fungal isolates were obtained. Koch's postulates were developed, and the results showed that Nothophoma juglandis, a species new to science, was the causal agent of walnut heart rot disease. Granulobasidium vellereum, a notable biocontrol agent, was coisolated with N. juglandis. An antagonistic assay on dual culture and walnut stems (both in the field and detached branches) proved that G. vellereum acted as a potential biocontrol agent against N. juglandis, as it could significantly inhibit the expansion of N. juglandis. The optimal temperature for mycelial growth and pathogenicity of N. juglandis was 26.6 and 27.0°C, respectively, which frequently occur in the summer of the walnut-growing regions in China.
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Affiliation(s)
- Lili Zhao
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Wei Sun
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Lin Zhang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yueqi Yin
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yuqing Xie
- School of Biological Science and Technology, Beijing Forestry University, Beijing, China
| | - Ying Zhang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
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López-Moral A, Agustí-Brisach C. Isolation and Reproductive Structures Induction of Fungal Pathogens Associated with Xylem and Wood Necrosis in Grapevine. Methods Mol Biol 2024; 2722:107-115. [PMID: 37897603 DOI: 10.1007/978-1-0716-3477-6_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/30/2023]
Abstract
Grapevine (Vitis vinifera L.) trunk diseases (GTDs) are considered a disease complex including five diseases: esca, Petri disease, black-foot disease, Botryosphaeria dieback, and Eutypa dieback. The main symptom is a general decline in affected plants, which show xylem necrosis and discoloration or sectorial necrosis in the wood. Their diagnosis is tedious due to four main reasons: (i) the wide diversity of internal symptoms that we can find; (ii) the great diversity of fungi that are associated with them; (iii) the high frequency of co-infections in the same plant; and (iv) the different behavior that the fungal species associated with GTDs show in vitro. Here, we describe a detailed protocol to isolate the different fungal trunk pathogens associated with GTDs as well as methods to induce sporulation and formation of fruiting bodies (pycnidia) to make easier their morphological characterization.
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Affiliation(s)
- Ana López-Moral
- Department of Agronomy (DAUCO, Unit of Excellence María de Maeztu 2020-24), University of Cordoba, Cordoba, Spain
| | - Carlos Agustí-Brisach
- Department of Agronomy (DAUCO, Unit of Excellence María de Maeztu 2020-24), University of Cordoba, Cordoba, Spain.
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3
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Antón-Domínguez BI, López-Moral A, Raya MC, Lovera M, Melgar S, Roca LF, Arquero O, Trapero A, Agustí-Brisach C. Fungal Pathogens Associated with Almond Decline Syndrome, an Emerging Disease Complex in Intensive Almond Crops in Southern Spain. PLANT DISEASE 2023; 107:3737-3753. [PMID: 37486269 DOI: 10.1094/pdis-04-23-0759-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
In 2016, an almond (Prunus dulcis) decline syndrome (ADS) emerged in intensive almond plantations in the Andalusia region (southern Spain), showing branch dieback, gummosis, and general tree decline. The aim of this work was to elucidate the etiology of this disease complex. For this purpose, surveys were conducted across the Andalusia region, and a wide collection of fungi was recovered from wood samples showing gum and internal discoloration. Representative isolates were selected and identified by sequencing ITS, TEF1, TUB, ACT, LSU, and/or RPB2 genes. The following fungal species were identified to be associated with the disease: Botryosphaeria dothidea, Diplodia corticola, Di. seriata, Dothiorella iberica, Lasiodiplodia viticola, Macrophomina phaseolina, Neofusicoccum mediterraneum, N. parvum, N. vitifusiforme, Diaporthe neotheicola, Dia. rhusicola, Dia. ambigua, Eutypa lata, E. tetragona, Eutypella citricola, Eu. microtheca, Fusarium oxysporum s.l., Pleurostoma richardsiae, Phaeoacremonium iranianum, Pm. krajdenii, Pm. parasiticum, and Cytospora sp. All isolates were tested for pathogenicity by inoculating detached or attached almond shoots. Di. corticola and N. parvum were the most aggressive species, showing the largest lesions and most gummosis in attached shoots. The results suggest that the species belonging to Botryosphaeriaceae play a key role in disease development, while the remaining identified species may act as secondary pathogens or endophytes. However, further research to determine the interaction between all these fungal species and other biotic and abiotic factors in the ADS progress is needed.
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Affiliation(s)
- Begoña I Antón-Domínguez
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Ana López-Moral
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - María Carmen Raya
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - María Lovera
- Departamento de Fruticultura Mediterránea, IFAPA, Alameda del Obispo, 14004 Córdoba, Spain
| | - Samara Melgar
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Luis F Roca
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Octavio Arquero
- Departamento de Fruticultura Mediterránea, IFAPA, Alameda del Obispo, 14004 Córdoba, Spain
| | - Antonio Trapero
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Carlos Agustí-Brisach
- Departamento de Agronomía (Unit of Excellence 'María de Maeztu' 2020-24), ETSIAM, Universidad de Córdoba, 14071 Córdoba, Spain
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López-Moral A, Lovera M, Antón-Domínguez BI, Gámiz AM, Michailides TJ, Arquero O, Trapero A, Agustí-Brisach C. Effects of Cultivar Susceptibility, Branch Age, and Temperature on Infection by Botryosphaeriaceae and Diaporthe Fungi on English Walnut ( Juglans regia). PLANT DISEASE 2022; 106:2920-2926. [PMID: 35380463 DOI: 10.1094/pdis-09-21-2042-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Botryosphaeriaceae and Diaporthe fungi have been described as the main causal agents of branch dieback and shoot blight of English walnut (Juglans regia L.). To date, the effects of biotic and abiotic factors on disease development on this host are still poorly understood. Thus, the main goal of this study was to evaluate the effects of cultivar, shoot-branch age, and temperature on infection by Botryosphaeriaceae and Diaporthe fungi on English walnut. The susceptibility of eight commercial cultivars was evaluated against three Botryosphaeriaceae and two Diaporthe species. For the remaining experiments, shoots or branches of 'Chandler' were used. An initial experiment evaluating two inoculation methods was conducted, with inoculation with a mycelial plug being more consistent and useful than conidial suspension inoculation. Cultivar susceptibility varied depending on the fungal species, with 'Chandler' being among the most tolerant cultivars for shoot infection. One-year-old shoots were significantly more sensitive for both Neofusicoccum parvum and Diaporthe neotheicola in comparison with 2- to 4-year-old branches. The effect of temperature on shoot infection was evaluated under 5, 10, 15, 20, 25, 30, and 35°C. Lesion development was significantly higher for N. parvum isolates than for D. neotheicola isolates at all temperatures evaluated, with optimum temperature of shoot infection being ∼26°C for N. parvum and ∼21°C for D. neotheicola.
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Affiliation(s)
- Ana López-Moral
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - María Lovera
- Departamento de Fruticultura Mediterránea, IFAPA, Alameda del Obispo, 14004 Córdoba, Spain
| | - Begoña I Antón-Domínguez
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - Antonio M Gámiz
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - Themis J Michailides
- Kearney Agricultural Research and Extension Center, University of California, Davis, Parlier, CA 93648, U.S.A
| | - Octavio Arquero
- Departamento de Fruticultura Mediterránea, IFAPA, Alameda del Obispo, 14004 Córdoba, Spain
| | - Antonio Trapero
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - Carlos Agustí-Brisach
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
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Xu XL, Wang FH, Liu C, Yang HB, Zeng Z, Wang BX, Liu YG, Yang CL. Morphology and phylogeny of ascomycetes associated with walnut trees ( Juglans regia) in Sichuan province, China. Front Microbiol 2022; 13:1016548. [PMID: 36338097 PMCID: PMC9632355 DOI: 10.3389/fmicb.2022.1016548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/20/2022] [Indexed: 01/28/2023] Open
Abstract
In Sichuan province, walnuts, consisting of Juglans regia, Juglans sigillata, and the hybrid J. regia × J. sigillata, are commercially important edible nuts, and J. regia is the most widespread plant. To date, the diversity and distribution of fungi inhabiting on Juglans have not received enough attention, although there have been studies focusing on pathogens from fruit and stem. In order to update the checklist of fungi associated with Sichuan walnuts, a survey on fungi associated with the three Juglans species from 15 representative regions in Sichuan was conducted. In this article, ten fungi distributed in two classes of Ascomycota (Dothideomycetes and Sordariomycetes) were described based on morpho-molecular analyses, and two novel species, Neofusicoccum sichuanense and Sphaerulina juglandina, a known species of Ophiognomonia leptostyla, and seven new hosts or geographical records of Cladosporium tenuissimum, Diatrypella vulgaris, Helminthosporium juglandinum, Helminthosporium velutinum, Loculosulcatispora hongheensis, Periconia byssoides, and Rhytidhysteron subrufulum were included. Morphological descriptions and illustrations of these fungi are provided.
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Affiliation(s)
- Xiu-Lan Xu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China,Forestry Research Institute, Chengdu Academy of Agricultural and Forestry Sciences, Chengdu, Sichuan, China
| | - Fei-Hu Wang
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Chao Liu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Han-Bo Yang
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Zhen Zeng
- Forestry Research Institute, Chengdu Academy of Agricultural and Forestry Sciences, Chengdu, Sichuan, China,*Correspondence: Zhen Zeng,
| | - Bao-Xin Wang
- Forestry Research Institute, Chengdu Academy of Agricultural and Forestry Sciences, Chengdu, Sichuan, China
| | - Ying-Gao Liu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Chun-Lin Yang
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River and Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, College of Forestry, Sichuan Agricultural University, Chengdu, Sichuan, China,Chun-Lin Yang,
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6
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López-Moral A, Agustí-Brisach C, Raya MDC, Lovera M, Trapero C, Arquero O, Trapero A. Etiology of Septoria Leaf Spot of Pistachio in Southern Spain. PLANT DISEASE 2022; 106:406-417. [PMID: 34472969 DOI: 10.1094/pdis-02-21-0331-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Septoria leaf spot (SLS) is the most prevalent disease of pistachio (Pistacia vera L.) in Spain. To elucidate its etiology, 22 samples of pistachio leaves showing SLS symptoms were collected mainly from 1993 to 2018 across southern Spain. Affected leaves from terebinth (P. terebinthus) were also collected for comparative purposes. Six Septoria-like isolates were recovered from pistachio leaves. They were identified as S. pistaciarum by sequencing internal transcribed spacers, partial RNA polymerase II second largest subunit locus, and 28S ribosomal RNA genes. The phenotypic characteristics of conidia and colonies were evaluated, confirming the identity of S. pistaciarum. Conidia were solitary, hyaline, and straight to curved. Large differences in length were observed between conidia from leaf samples, with those from terebinth being slightly larger than those from pistachio. Colonies showed slow mycelial growth on potato dextrose agar (PDA). The effect of temperature on conidial germination and mycelial growth was evaluated in vitro on PDA. For both characters, the optimum temperature was approximately 19 to 20°C. Eight culture media were tested, with oatmeal agar and Spezieller Nährstoffarmer agar showing the highest mycelial growth and pistachio leaf agar (PLA) showing the highest sporulation. A specific culture medium integrating lyophilized-powdered pistachio leaves into diluted PDA improved sporulation compared with PLA. Pathogenicity tests were conducted by inoculating detached and in planta pistachio and terebinth leaflets with conidial suspensions. Typical symptoms of SLS and cirri of S. pistaciarum developed at 10 and 21 days after inoculation, respectively, in both hosts. To our knowledge, this is the first report of S. pistaciarum causing SLS in pistachio and terebinth in Spain.
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Affiliation(s)
- Ana López-Moral
- Departamento de Agronomía, Unit of Excellence "María de Maeztu" 2020-23, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Carlos Agustí-Brisach
- Departamento de Agronomía, Unit of Excellence "María de Maeztu" 2020-23, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - María Del Carmen Raya
- Departamento de Agronomía, Unit of Excellence "María de Maeztu" 2020-23, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - María Lovera
- Departamento de Fruticultura Mediterránea, Andalusian Agricultural and Fisheries Research and Training Institute, 14004 Córdoba, Spain
| | - Carlos Trapero
- Departamento de Agronomía, Unit of Excellence "María de Maeztu" 2020-23, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Octavio Arquero
- Departamento de Fruticultura Mediterránea, Andalusian Agricultural and Fisheries Research and Training Institute, 14004 Córdoba, Spain
| | - Antonio Trapero
- Departamento de Agronomía, Unit of Excellence "María de Maeztu" 2020-23, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
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Agustí-Brisach C, Moldero D, Raya MDC, Lorite IJ, Orgaz F, Trapero A. Water Stress Enhances the Progression of Branch Dieback and Almond Decline under Field Conditions. PLANTS (BASEL, SWITZERLAND) 2020; 9:plants9091213. [PMID: 32947913 PMCID: PMC7570136 DOI: 10.3390/plants9091213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/10/2020] [Accepted: 09/13/2020] [Indexed: 06/11/2023]
Abstract
Branch dieback and tree decline have been described as a common complex disease worldwide in woody crops, with Botryosphaeriaceae and Diaporthaceae being considered the most frequent fungi associated with the disease symptoms. Their behaviour is still uncertain, since they are considered endophytes becoming pathogenic in weakened hosts when stress conditions, such as water deficiency occur. Therefore, the main goal of this study was to determine if water stress enhances general decline on weakened almond trees subjected to different irrigation treatments under natural field conditions. In parallel, the occurrence of fungal species associated with almond decline was also determined in relation to disease progression by fungal isolation, and morphological and molecular based-methods. The symptoms of branch dieback and general decline were observed over time, mainly in the experimental plots subjected to high water deficiency. Botryosphaeriaceae were the most consistently isolated fungi, and Botryosphaeria dothidea was the most frequent. Collophorina hispanica was the second most frequent species and Diaporthe and Cytospora species were isolated in a low frequency. Most of them were recovered from both asymptomatic and symptomatic trees, with their consistency of isolation increasing with the disease severity. This work reveals the need to elucidate the role of biotic and abiotic factors which increase the rate of infection of fungal trunk pathogens, in order to generate important knowledge on their life cycle.
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Affiliation(s)
- Carlos Agustí-Brisach
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain; (M.d.C.R.); (A.T.)
| | - David Moldero
- Instituto de Agricultura Sostenible (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Campus Alameda del Obispo, Avda Menéndez Pidal s/n, 14004 Córdoba, Spain; (D.M.); (F.O.)
| | - María del Carmen Raya
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain; (M.d.C.R.); (A.T.)
| | - Ignacio J. Lorite
- IFAPA-Centro Alameda del Obispo, Junta de Andalucía, Avda Menéndez Pidal s/n, 14004 Córdoba, Spain;
| | - Francisco Orgaz
- Instituto de Agricultura Sostenible (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Campus Alameda del Obispo, Avda Menéndez Pidal s/n, 14004 Córdoba, Spain; (D.M.); (F.O.)
| | - Antonio Trapero
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain; (M.d.C.R.); (A.T.)
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Eichmeier A, Pecenka J, Spetik M, Necas T, Ondrasek I, Armengol J, León M, Berlanas C, Gramaje D. Fungal Trunk Pathogens Associated With Juglans regia in the Czech Republic. PLANT DISEASE 2020; 104:761-771. [PMID: 31944904 DOI: 10.1094/pdis-06-19-1308-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Juglans regia L. (English walnut) trees with cankers and dieback symptoms were observed in two regions in the Czech Republic. Isolations were made from diseased branches. In total, 138 fungal isolates representing 10 fungal species were obtained from wood samples and identified based on morphological characteristics and molecular methods: Cadophora novi-eboraci, Cadophora spadicis, Cryptovalsa ampelina, Diaporthe eres, Diplodia seriata, Dothiorella omnivora, Eutypa lata, Eutypella sp., Peroneutypa scoparia, and Phaeoacremonium sicilianum. Pathogenicity tests conducted under field conditions with all species using the mycelium-plug method indicated that Eutypa lata and Cadophora spp. were highly virulent to woody stems of walnut. This is the first study to detect and identify fungal trunk pathogens associated with diseased walnut trees in Europe.
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Affiliation(s)
- A Eichmeier
- Mendeleum Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, 69144 Lednice, Czech Republic
| | - J Pecenka
- Mendeleum Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, 69144 Lednice, Czech Republic
| | - M Spetik
- Mendeleum Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, 69144 Lednice, Czech Republic
| | - T Necas
- Department of Fruit Growing, Faculty of Horticulture, Mendel University in Brno, 69144 Lednice, Czech Republic
| | - I Ondrasek
- Department of Fruit Growing, Faculty of Horticulture, Mendel University in Brno, 69144 Lednice, Czech Republic
| | - J Armengol
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, 46022 Valencia, Spain
| | - M León
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, 46022 Valencia, Spain
| | - C Berlanas
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas, Universidad de la Rioja, Gobierno de La Rioja, 26007 Logroño, Spain
| | - D Gramaje
- Instituto de Ciencias de la Vid y del Vino, Consejo Superior de Investigaciones Científicas, Universidad de la Rioja, Gobierno de La Rioja, 26007 Logroño, Spain
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López-Moral A, Lovera M, Raya MDC, Cortés-Cosano N, Arquero O, Trapero A, Agustí-Brisach C. Etiology of Branch Dieback and Shoot Blight of English Walnut Caused by Botryosphaeriaceae and Diaporthe Species in Southern Spain. PLANT DISEASE 2020; 104:533-550. [PMID: 31746696 DOI: 10.1094/pdis-03-19-0545-re] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
English walnut (Juglans regia L.) is considered an economically important fruit crop worldwide. In Spain, little attention has been given to walnut diseases owing to the minor economic importance of the walnut crop in the country until recently. In 2017, typical symptoms of branch dieback and shoot blight of English walnut were observed in southern Spain. From 2017 to 2018, 10 commercial walnut orchards showing disease symptoms were surveyed. Botryosphaeriaceae and Diaporthe fungi were consistently isolated from affected shoots. Cytospora isolates were also recovered with minor relevance. Representative isolates of each fungal group were characterized based on colony and conidial morphology, optimum growth temperature, and comparison of DNA sequence data from the internal transcribed spacer, elongation factor 1-α, and β-tubulin genomic areas. Pathogenicity tests were performed on detached and attached shoots and on detached fruit by inoculating them with mycelial plugs. Botryosphaeriaceae and Diaporthe isolates had higher optimum growth temperatures (≈25 to 27°C) than Cytospora sp. (19.5°C). The following species were identified: Botryosphaeriaceae: Botryosphaeria dothidea, Diplodia seriata, Dothiorella sarmentorum, Dothiorella sp., Neofusicoccum mediterraneum, and N. parvum; Diaporthe: Diaporthe neotheicola, Dia. rhusicola, Diaporthe sp., and Phomopsis amygdali; and Cytospora sp. Botryosphaeriaceae isolates were the most aggressive fungi to walnut in all tissues evaluated, followed by Diaporthe isolates and Cytospora sp. N. parvum was the most virulent among the remaining species tested in any of the tissues evaluated, followed by B. dothidea or N. mediterraneum. This work is the first report to identify the fungal species causing this complex disease of English walnut in Spain and Europe.
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Affiliation(s)
- Ana López-Moral
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - María Lovera
- Departamento de Fruticultura Mediterránea, IFAPA, 14004 Córdoba, Spain
| | - María Del Carmen Raya
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Nerea Cortés-Cosano
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Octavio Arquero
- Departamento de Fruticultura Mediterránea, IFAPA, 14004 Córdoba, Spain
| | - Antonio Trapero
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Carlos Agustí-Brisach
- Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
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Moral J, Morgan D, Trapero A, Michailides TJ. Ecology and Epidemiology of Diseases of Nut Crops and Olives Caused by Botryosphaeriaceae Fungi in California and Spain. PLANT DISEASE 2019; 103:1809-1827. [PMID: 31232653 DOI: 10.1094/pdis-03-19-0622-fe] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In recent decades, the cultivated area and production of nuts and olives have increased, driven by an increasing consumer interest in healthier food. Diseases of almond, pistachio, olive, and walnut crops caused by species belonging to the Botryosphaeriaceae family have caused concern worldwide. Although considerable progress has been made in elucidating the etiology of these diseases, scientific knowledge of other aspects of these diseases is more limited. In this article, we present an overview of the most important diseases caused by Botryosphaeriaceae fungi affecting almond, pistachio, olive, and walnut crops by focusing on ecology and epidemiology, primarily in California and Spain.
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Affiliation(s)
- Juan Moral
- 1Department of Plant Pathology, University of California, Davis, Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
- 2Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - David Morgan
- 1Department of Plant Pathology, University of California, Davis, Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
| | - Antonio Trapero
- 2Departamento de Agronomía, ETSIAM, Universidad de Córdoba, Campus de Rabanales, Edif. C4, 14071 Córdoba, Spain
| | - Themis J Michailides
- 1Department of Plant Pathology, University of California, Davis, Kearney Agricultural Research and Extension Center, Parlier, CA 93648, U.S.A
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