Characterization of Cadophora luteo-olivacea and C. melinii isolates obtained from grapevines and environmental samples from grapevine nurseries in Spain

[EN] Fifty-eight Cadophora luteo-olivacea and three C. melinii isolates were recovered from grapevines showing black vascular streaking and decline symptoms characteristic of Petri disease, and from different stages of the grapevine nursery process in Spain. The isolates were studied by means of phenotypical characterization, DNA analysis and pathogenicity tests. The morphological characters studied included conidiophore, phialide and conidial morphology. Colony characters and pigment production on MEA, PDA and OA were also examined. Phenotypical data were subjected to cluster analysis, which clearly separated C. luteo-olivacea isolates into four groups. Mating tests were performed on all possible combinations for each Cadophora species but no sexual fruiting bodies were produced. Partial sequences of the nuclear ribosomal internal transcribed spacer (ITS), beta-tubulin (BT) and the elongation factor 1¿ (EF) were analysed, but no genetic variation occurred within the C. luteo-olivacea isolates or within the C. melinii isolates in any of the regions studied. Pathogenicity tests were conducted on 1-year-old grapevine cuttings of four different rootstocks using four C. luteo-olivacea isolates and one isolate of C. melinii. All Cadophora isolates except the C. melinii isolate caused significantly longer lesions in the xylem of grapevine rootstocks than in the controls.This research was financially supported by the Projects AGL2006-11884-C04-01 (Ministerio de Educación y Ciencia, Spain), RTA2007-00023-C04-03 and RTA2010-00009-C03-03 (Programa Nacional de Recursos y Tecnologías Agrarias, Ministerio de Educación y Ciencia, Spain), and the European Regional Development Fund (ERDF). We thank V. Garrigues for technical assistance.Gramaje, D.; Mostert, L.; Armengol Fortí, J. (2011). Characterization of Cadophora luteo-olivacea and C. melinii isolates obtained from grapevines and environmental samples from grapevine nurseries in Spain. Phytopathologia Mediterranea. 50(Supplement):112-126. https://doi.org/10.14601/Phytopathol_Mediterr-8723S11212650Supplemen

Field evaluation of grapevines rootstocks inoculated with fungi associated with Petri disease and esca

[EN] One year old grapevine rootstock cuttings of 41B Millardet Grasset 140 Ruggeri 161 49 Couderc 1103 Paulsen and 110 Richter were inoculated with pathogens associated with Petri disease and esca of grapevine to determine the effects of fungal infection on percentage of cuttings emerging from dormancy shoot weight and disease severity The cuttings were vacuum inoculated with spore suspensions of either Cadophora luteo olivacea five species of Phaeoacremonium or Phaeomoniella chlamydospora and planted in two field sites in March 2008 Most of the fungal pathogens caused a significant reduction in the percentage of cuttings emerging from dormancy and shoot weight and a significant increase in disease severity in all grapevine rootstocks except 161 49 Couderc Rootstocks 110 Richter and 140 Ruggeri were greatly affected by fungi associated with Petri disease and esca In general Pa chlamydospora and Pm parasiticum caused the greatest reduction in percentage of cuttings emerging from dormancy and shoot weight and the highest increase in disease severity Regression analyses showed a significant correlation between percentage of cuttings emerging from dormancy and disease severity and between shoot weight and disease severity in almost all rootstocks inoculated with Pa chlamydosporaThis research was financially supported by project RTA2007 00023 C04 03 (Programa Nacional de Recursos y Tecnologias Agrarias Ministerio de Educacion y Ciencia Spain)Gramaje, D.; García-Jiménez, J.; Armengol Fortí, J. (2010). Field evaluation of grapevines rootstocks inoculated with fungi associated with Petri disease and esca. American Journal of Enology and Viticulture. 61(4):512-520. https://doi.org/10.5344/ajev.2010.1002151252061

First report of Dactylonectria alcacerensis, Dactylonectria macrodidyma and Ilyonectria liriodendri associated with black-foot disease of grapevine in Argentina

Black-foot is a fungal disease that affects young vines and planting material in the countries where grapevines are cultivated. During the 2018 grape-growing season, symptoms of reduced vigor, short internodes, leaf chlorosis, root rot and necrosis in the base of plants were observed in vines between 2 to 10 years old from 400 ha of vineyards of Mendoza and Salta regions. A total of 30% of the vineyards of cultivars Malbec, Cabernet Sauvignon and Aspirant Bouchet, and rootstocks 101-14 Millardet et de Grasset and 1103 Paulsen, had vines with disease symptoms. Vines had 15% disease incidence and 30% disease severity. These symptoms have been described as characteristic of black-foot, caused by "Cylindrocarpon"-like asexual morph fungi. Isolations were made from roots and basal part of 30 symptomatic plants. Fragments of advanced necrotic tissue were washed with running water, surface sterilized with 70% alcohol for 20 seconds, 2% NaOCl solution for 4 minutes and rinsed in sterile distilled water twice. These fragments were placed onto Potato Dextrose Agar (PDA) and incubated at 25°C in the dark for 10 days to isolate fungal pathogens. A total of 50 colonies resembling black-foot disease pathogens were subcultured onto fresh PDA in order to obtain single spore cultures. The isolates developed buff to cinnamon and dark brown, and felty mycelium. Colonies subcultured in synthetic nutrient agar (SNA) produced hyaline, cylindrical, straight and/or slightly curved with one to three septate (35.6 × 5.3 µm) macroconidia and abundant, hyaline, ellipsoidal and zero to one septate (12.5 × 6.0 µm) microconidia. Cultures and conidia morphological characteristics were similar to those of Ilyonectria or Dactylonectria genera (Cabral et al. 2012a; Lombard et al. 2014). DNA sequence analysis of the partial histone H3 gene was obtained for isolates INTA SC1 (I. liriodendri), INTA LC2 (D. alcacerensis) and INTA LC1 (D. macrodidyma) and deposited in GenBank (accession nos. OK338901, OK338900 and OK338899). The BLAST search was conducted against type specimens. Sequences showed high similarity (99% to 100%) to the sequences of Ilyonectria liriodendri (Halleen, Rego & Crous) Chaverri & Salgado (GenBank accession no. JF735509), Dactylonectria alcacerensis (A. Cabral, Oliveira & Crous) L. Lombard & Crous (GenBank accession no. JF735630) and Dactylonectria macrodidyma (Halleen, Schroers & Crous) L. Lombard & Crous (GenBank accession no. JF735647). Pathogenicity tests were conducted under greenhouse conditions on 1-year-old rooted canes cv Malbec using the three isolates. Ten rooted cuttings with pruned roots were immersed in a suspension of 106 conidia ml-1 of each isolate for 60 min (Cabral et al. 2012b) while control cuttings were immersed in sterile distilled water. Immediately they were planted in pots and kept in a greenhouse at a temperature between 25 to 30°C. Symptoms developed on all plants 4 months after inoculation and consisted in necrotic lesions of roots and in the base of the canes, with a reduction in root biomass. Plants did not develop aerial symptoms. All fungi were re-isolated only from necrotic lesions of root and base of inoculated canes, fulfilling Koch's postulates. No symptoms were observed on the control plants. To our knowledge, this is the first report of the species I. liriodendri, D. alcacerensis and D. macrodidyma associated with black-foot disease of grapevine in Argentina. Black-foot disease has a negative effect on the viability of planting material and young vines, and this report will assist with monitoring distribution of the disease as well as developing management recommendations to nurseries and grape growers in Argentina.EEA MendozaFil: Longone, Maria Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Escoriaza, Maria Georgina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Paolinelli, Marcos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Gramaje, David. Universidad de la Rioja. Instituto de Ciencias de la Vid y del Vino; España. Consejo Superior de Investigaciones Científicas. Instituto de Ciencias de la Vid y del Vino; Españ

Identifying practices likely to have impacts on grapevine trunk disease infections: a European nursery survey

A questionnaire covering all aspects of grapevine propagation including cultural and sanitation practices in mother blocks and harvest and transport of cuttings from mother blocks to nurseries, nursery operations and field nursery management, was mailed to all Management Committee members of the European COST Action FA1303 “Sustainable Control of Grapevine Trunk Diseases” for distribution to the identifiable nurseries in each European country. The main objective was to develop understanding of the current propagation practices and to identify those likely to have the greatest impacts on the quality of planting material, especially with regard to the control measures used against fungal trunk pathogen infections. The questionnaire was sent to 666 vine nurseries, and 146 replies were received (21.9% response rate) The study identified several risks factors which could increase infection by fungal trunk pathogens during the propagation processes, as well as a clear need for further research into the effects of treatments on grapevine viability, including hot water treatment, and the potential of biological agents and other strategies such as ozonation to control grapevine trunk diseases in nurseries

Evaluation of fungicides to protect pruning wounds from Botryosphaeriaceae species infections on almond trees

In vitro efficacy of ten fungicides was evaluated against four Botryosphaeriaceae spp. (Diplodia seriata, Neofusicoccum luteum, N. mediterraneum and N. parvum) associated with branch cankers on almond trees. Cyproconazole, pyraclostrobin, tebuconazole, and thiophanate-methyl were effective for the inhibition of mycelial growth of most of these fungi. An experiment on 3-year-old almond trees evaluated boscalid, mancozeb, thiophanate-methyl, pyraclostrobin and tebuconazole for preventative ability against infections caused by the four pathogens. Five months after pruning and fungicide application, lesion length measurements and isolation percentages showed no significant differences among the four pathogens after they were inoculated onto the trees, and also between the two inoculation times tested (1 or 7 d after fungicide application). Thiophanate-methyl was the most effective fungicide, resulting in the shortest lesion lengths and the lowest isolation percentages from artificially inoculated pruning wounds. This chemical is therefore a candidate for inclusion in integrated disease management, to protect pruning wounds from infections caused by species of Botryosphaeriaceae. This study represents the first approach to development of chemical control strategies for the management of canker diseases caused by Botryosphaeriaceae fungi on almond trees.

Phaeoacremonium tuscanicum and Phaeoacremonium indicum sp. nov. associated with subcutaneous phaeohyphomycosis

Two cases of phaeohyphomycotic infections were caused by Phaeoacremonium tuscanicum, not previously identified in human infections, and one new species, Phaeoacremonium indicum, respectively. Morphological and cultural investigation as well as phylogenetic analysis was constructed based on maximum likelihood analyses using actin and -tubulin sequences to identify the fungal isolates.The authors acknowledge the contribution to the isolation and identification of the Phaeoacremonium indicum isolate made by: A.A. Padhye and A. Sivaraman (PSG Institute of Medical Science and Research, Coimbatore), S. Verghese (Frontier Life Line Private Limited, Mogappair), P. Ravichandran (Kidney Diseases and Institute of Organ Transplantation, St. Thomas Hospital, Chennai), Tay Sun Tee (Department of Medical Microbiology, University of Malaya), and Mary E. Brandt (Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta).Peer reviewe

Effect of hot-water treatments above 50 ºC on grapevine viability and survival of Petri disease pathogens

[EN] Rootstocks (41 B Mgt., 140 Ruggeri, 161-49 Couderc, 1103 Paulsen and 110 Richter) and scion/rootstock combinations (Bobal/1103 P, Merlot/110 R, Tempranillo/110 R and Tempranillo/161-49 C) were hot-water treated (HWTed) at 50, 51, 52. 53, or 54 degrees C for three periods: 30, 45 or 60 min. Four groups of 10 cuttings were treated for each temperature and time, and four additional groups of 10 untreated cuttings were prepared as controls. At the end of the growing season, cutting sprouting and shoot weight were evaluated. In a second experiment, healthy cuttings of '110 R' rootstock were vacuum-inoculated with conidial suspensions (10(6) conidia mL(-1)) of one isolate of either Phaeomoniella chlamydospora or Phaeoacremonium aleophilum. These cuttings were subjected to the treatments indicated above. Four groups of 10 cuttings were treated for each temperature, time and isolate, with their respective controls. Isolations were made immediately after the treatments and at the end of the growing season, when cutting sprouting and shoot weight were evaluated. Results demonstrated that it is possible to hot-water treat grapevine planting material in Spanish nurseries using protocols with temperatures of up to 50 degrees C. HWTs at 53 degrees C are able to eliminate Pa. chlamydospora completely and Strongly reduce the re-isolation of Pm. aleophilum from grapevine wood. These findings will contribute to the development of an effective control for Petri disease in grapevine propagating material in Spanish grapevine nurseries.This research was financially supported by the Projects AGL2006-11884-C04-01 (Ministerio de Educacion y Ciencia, Spain) and TRT2006-00033-00-0 and RTA2007-00023-C04-03 (Programa Nacional de Recursos y Tecnologias Agrarias, Ministerio de Educacion y Ciencia, Spain). We acknowledge A. Crespo, E. H. Albaranez, A. Gimenez-Jaime and T. Zaragoza for technical assistance, and G. Brodie for statistical advice.Gramaje, D.; Armengol Fortí, J.; Salazar Hernández, DM.; López- Cortés, I.; García-Jiménez, J. (2009). Effect of hot-water treatments above 50 ºC on grapevine viability and survival of Petri disease pathogens. Crop Protection. 28(3):280-285. https://doi.org/10.1016/j.cropro.2008.11.00228028528