Searching for grapevine fungal trunk pathogens on cover crop roots

The potential role of cover crops as alternative hosts for soil-borne fungi plant diseases has not been thoroughly explored. Root samples from cover crops from experimental plots in the CORE Organic Cofund BIOVINE project has been analysed to find out more

Evaluation of long-term protection from nursery to vineyard provided by Trichoderma atroviride SC1 against fungal grapevine trunk pathogens

This is the peer reviewed version of the following article: Berbegal, M., Ramón¿Albalat, A., León, M. and Armengol, J. (2020), Evaluation of long¿term protection from nursery to vineyard provided by Trichoderma atroviride SC1 against fungal grapevine trunk pathogens. Pest. Manag. Sci., 76: 967-977, which has been published in final form at https://doi.org/10.1002/ps.5605. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] BACKGROUND Fungal grapevine trunk diseases (GTDs) represent a threat to viticulture, being responsible for important economic losses worldwide. Nursery and vineyard experiments were set up to evaluate the ability of Trichoderma atroviride SC1 to reduce infections of GTD pathogens in grapevine planting material during the propagation process and to assess the long-term protection provided by this biocontrol agent on grapevine plants in young vineyards during two growing seasons. RESULTS Reductions of some GTD pathogen incidence and severity were found on grapevine propagation material after nursery application of T. atroviride SC1 during the grafting process, and also after additional T. atroviride SC1 treatments performed during two growing seasons in young vineyards, when compared with untreated plants. CONCLUSION Trichoderma atroviride SC1 showed promise to reduce infections caused by some GTD pathogens in nurseries, and also when establishing new vineyards. This biological control agent could possibly be a valuable component in an integrated management approach where various strategies are combined to reduce GTD infections.Berbegal Martinez, M.; Ramón-Albalat, A.; León Santana, M.; Armengol Fortí, J. (2020). Evaluation of long-term protection from nursery to vineyard provided by Trichoderma atroviride SC1 against fungal grapevine trunk pathogens. Pest Management Science. 76(3):967-977. https://doi.org/10.1002/ps.5605S967977763Gramaje, D., Úrbez-Torres, J. R., & Sosnowski, M. R. (2018). Managing Grapevine Trunk Diseases With Respect to Etiology and Epidemiology: Current Strategies and Future Prospects. Plant Disease, 102(1), 12-39. doi:10.1094/pdis-04-17-0512-feMondello, V., Songy, A., Battiston, E., Pinto, C., Coppin, C., Trotel-Aziz, P., … Fontaine, F. (2018). Grapevine Trunk Diseases: A Review of Fifteen Years of Trials for Their Control with Chemicals and Biocontrol Agents. Plant Disease, 102(7), 1189-1217. doi:10.1094/pdis-08-17-1181-feGramaje, D., & Armengol, J. (2011). Fungal Trunk Pathogens in the Grapevine Propagation Process: Potential Inoculum Sources, Detection, Identification, and Management Strategies. Plant Disease, 95(9), 1040-1055. doi:10.1094/pdis-01-11-0025Kaplan, J., Travadon, R., Cooper, M., Hillis, V., Lubell, M., & Baumgartner, K. (2016). Identifying economic hurdles to early adoption of preventative practices: The case of trunk diseases in California winegrape vineyards. Wine Economics and Policy, 5(2), 127-141. doi:10.1016/j.wep.2016.11.001Úrbez-Torres, J. R., & Gubler, W. D. (2010). Susceptibility of grapevine pruning wounds to infection by Lasiodiplodia theobromae and Neofusicoccum parvum. Plant Pathology, 60(2), 261-270. doi:10.1111/j.1365-3059.2010.02381.xEskalen, A., Feliciano, A. J., & Gubler, W. D. (2007). Susceptibility of Grapevine Pruning Wounds and Symptom Development in Response to Infection by Phaeoacremonium aleophilum and Phaeomoniella chlamydospora. Plant Disease, 91(9), 1100-1104. doi:10.1094/pdis-91-9-1100Elena, G., & Luque, J. (2016). Seasonal Susceptibility of Grapevine Pruning Wounds and Cane Colonization in Catalonia, Spain Following Artificial Infection with Diplodia seriata and Phaeomoniella chlamydospora. Plant Disease, 100(8), 1651-1659. doi:10.1094/pdis-10-15-1186-reDíaz, G. A., & Latorre, B. A. (2013). Efficacy of paste and liquid fungicide formulations to protect pruning wounds against pathogens associated with grapevine trunk diseases in Chile. Crop Protection, 46, 106-112. doi:10.1016/j.cropro.2013.01.001Harman, G. E., & Kubicek, C. P. (Eds.). (1998). Trichoderma And Gliocladium, Volume 2. doi:10.1201/9781482267945Harman, G. E. (2000). Myths and Dogmas of Biocontrol Changes in Perceptions Derived from Research on Trichoderma harzinum T-22. Plant Disease, 84(4), 377-393. doi:10.1094/pdis.2000.84.4.377Mukherjee, M., Mukherjee, P. K., Horwitz, B. A., Zachow, C., Berg, G., & Zeilinger, S. (2012). Trichoderma–Plant–Pathogen Interactions: Advances in Genetics of Biological Control. Indian Journal of Microbiology, 52(4), 522-529. doi:10.1007/s12088-012-0308-5Rajesh, R. W., Rahul, M. S., & Ambalal, N. S. (2016). Trichoderma: A significant fungus for agriculture and environment. African Journal of Agricultural Research, 11(22), 1952-1965. doi:10.5897/ajar2015.10584Harman, G. E. (2006). Overview of Mechanisms and Uses of Trichoderma spp. Phytopathology®, 96(2), 190-194. doi:10.1094/phyto-96-0190Pieterse, C. M. J., Zamioudis, C., Berendsen, R. L., Weller, D. M., Van Wees, S. C. M., & Bakker, P. A. H. M. (2014). Induced Systemic Resistance by Beneficial Microbes. Annual Review of Phytopathology, 52(1), 347-375. doi:10.1146/annurev-phyto-082712-102340Van Wees, S. C., Van der Ent, S., & Pieterse, C. M. (2008). Plant immune responses triggered by beneficial microbes. Current Opinion in Plant Biology, 11(4), 443-448. doi:10.1016/j.pbi.2008.05.005Berlanas, C., Andrés-Sodupe, M., López-Manzanares, B., Maldonado-González, M. M., & Gramaje, D. (2018). Effect of white mustard cover crop residue, soil chemical fumigation and Trichoderma spp. root treatment on black-foot disease control in grapevine. Pest Management Science, 74(12), 2864-2873. doi:10.1002/ps.5078Fourie, P. H., & Halleen, F. (2006). Chemical and biological protection of grapevine propagation material from trunk disease pathogens. European Journal of Plant Pathology, 116(4), 255-265. doi:10.1007/s10658-006-9057-9Dissanayake, A. (2016). Botryosphaeriaceae: Current status of genera and species. Mycosphere, 7(7), 1001-1073. doi:10.5943/mycosphere/si/1b/13Mostert, L., Groenewald, J. Z., Summerbell, R. C., Gams, W., & Crous, P. W. (2006). Taxonomy and Pathology of Togninia (Diaporthales) and its Phaeoacremonium Anamorphs. Studies in Mycology, 54, 1-113. doi:10.3114/sim.54.1.1GARDES, M., & BRUNS, T. D. (1993). ITS primers with enhanced specificity for basidiomycetes - application to the identification of mycorrhizae and rusts. Molecular Ecology, 2(2), 113-118. doi:10.1111/j.1365-294x.1993.tb00005.xTravadon, R., Lawrence, D. P., Rooney-Latham, S., Gubler, W. D., Wilcox, W. F., Rolshausen, P. E., & Baumgartner, K. (2015). Cadophora species associated with wood-decay of grapevine in North America. Fungal Biology, 119(1), 53-66. doi:10.1016/j.funbio.2014.11.002O’Donnell, K., & Cigelnik, E. (1997). Two Divergent Intragenomic rDNA ITS2 Types within a Monophyletic Lineage of the FungusFusariumAre Nonorthologous. Molecular Phylogenetics and Evolution, 7(1), 103-116. doi:10.1006/mpev.1996.0376Jacobs, K., Bergdahl, D. R., Wingfield, M. J., Halik, S., Seifert, K. A., Bright, D. E., & Wingfield, B. D. (2004). Leptographium wingfieldii introduced into North America and found associated with exotic Tomicus piniperda and native bark beetles. Mycological Research, 108(4), 411-418. doi:10.1017/s0953756204009748Savazzini, F., Longa, C. M. O., Pertot, I., & Gessler, C. (2008). Real-time PCR for detection and quantification of the biocontrol agent Trichoderma atroviride strain SC1 in soil. Journal of Microbiological Methods, 73(2), 185-194. doi:10.1016/j.mimet.2008.02.004Longa, C. M. O., Pertot, I., & Tosi, S. (2008). Ecophysiological requirements and survival of aTrichoderma atrovirideisolate with biocontrol potential. Journal of Basic Microbiology, 48(4), 269-277. doi:10.1002/jobm.200700396Úrbez-Torres, J. R., Haag, P., Bowen, P., Lowery, T., & O’Gorman, D. T. (2015). Development of a DNA Macroarray for the Detection and Identification of Fungal Pathogens Causing Decline of Young Grapevines. Phytopathology®, 105(10), 1373-1388. doi:10.1094/phyto-03-15-0069-

Identification and characterization of Diaporthe spp. associated with twig cankers and shoot blight of almonds in Spain

[EN] Two hundred and twenty-fiveDiaportheisolates were collected from 2005 to 2019 in almond orchards showing twig cankers and shoot blight symptoms in five different regions across Spain. Multilocus DNA sequence analysis with five loci (ITS,tub,tef-1 alpha,calandhis), allowed the identification of four knownDiaporthespecies, namely:D. amygdali,D. eres,D. foeniculinaandD. phaseolorum. Moreover, a novel phylogenetic species,D. mediterranea, was described.Diaportheamygdaliwas the most prevalent species, due to the largest number of isolates (85.3%) obtained from all sampled regions. The second most frequent species wasD. foeniculina(10.2%), followed byD. mediterranea(3.6%),D.eresandD. phaseolorum, each with only one isolate. Pathogenicity tests were performed using one-year-old almond twigs cv. Vayro and representative isolates of the different species. Except forD. foeniculinaandD. phaseolorum, allDiaporthespecies were able to cause lesions significantly different from those developed on the uninoculated controls.Diaporthe mediterraneacaused the most severe symptoms. These results confirmD. amygdalias a key pathogen of almonds in Spain. Moreover, the new species,D. mediterranea, should also be considered as a potential important causal agent of twig cankers and shoot blight on this crop.Research funded by the Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), grants RTA2017-00009-C04-01, -02, -03 and -04 and with matching funds from the European Regional Development Fund (ERDF). G. Elena and C. Agusti-Brisach were supported by the Spanish post-doctoral grants "Juan de la Cierva-Formacion" and "Juan de la Cierva-Incorporacion", respectively. J. Luque and X. Miarnau were partially supported by the CERCA program, Generalitat de Catalunya. D. Gramaje was supported by the Ramon y Cajal program, Spanish Government (RYC-2017-23098).León Santana, M.; Berbegal Martinez, M.; Rodríguez-Reina, JM.; Elena, G.; Abad Campos, P.; Ramón-Albalat, A.; Olmo, D.... (2020). Identification and characterization of Diaporthe spp. associated with twig cankers and shoot blight of almonds in Spain. Agronomy. 10(8):1-23. https://doi.org/10.3390/agronomy10081062S123108Food and Agriculture Organization of the United Nationshttp://www.fao.org/faostat/es/#datDiogo, E. L. F., Santos, J. M., & Phillips, A. J. L. (2010). Phylogeny, morphology and pathogenicity of Diaporthe and Phomopsis species on almond in Portugal. Fungal Diversity, 44(1), 107-115. doi:10.1007/s13225-010-0057-xTuset, J. J., & Portilla, M. A. T. (1989). Taxonomic status of Fusicoccum amygdali and Phomopsis amygdalina. Canadian Journal of Botany, 67(5), 1275-1280. doi:10.1139/b89-168TUSET, J. J., HINAREJOS, C., & PORTILLA, M. T. (1997). Incidence of Phomopsis amygdali, Botryosphaeria berengeriana and Valsa cincta diseases in almond under different control strategies. EPPO Bulletin, 27(4), 449-454. doi:10.1111/j.1365-2338.1997.tb00664.xUdayanga, D., Liu, X., Crous, P. W., McKenzie, E. H. C., Chukeatirote, E., & Hyde, K. D. (2012). A multi-locus phylogenetic evaluation of Diaporthe (Phomopsis). Fungal Diversity, 56(1), 157-171. doi:10.1007/s13225-012-0190-9Rossman, A. Y., Adams, G. C., Cannon, P. F., Castlebury, L. A., Crous, P. W., Gryzenhout, M., … Walker, D. M. (2015). Recommendations of generic names in Diaporthales competing for protection or use. IMA Fungus, 6(1), 145-154. doi:10.5598/imafungus.2015.06.01.09Gomes, R. R., Glienke, C., Videira, S. I. R., Lombard, L., Groenewald, J. Z., & Crous, P. W. (2013). Diaporthe: a genus of endophytic, saprobic and plant pathogenic fungi. Persoonia - Molecular Phylogeny and Evolution of Fungi, 31(1), 1-41. doi:10.3767/003158513x666844Gao, Y., Liu, F., Duan, W., Crous, P. W., & Cai, L. (2017). Diaporthe is paraphyletic. IMA Fungus, 8(1), 153-187. doi:10.5598/imafungus.2017.08.01.11Dissanayake, A. (2017). The current status of species in Diaporthe. Mycosphere, 8(5), 1106-1156. doi:10.5943/mycosphere/8/5/5Santos, L., Alves, A., & Alves, R. (2017). Evaluating multi-locus phylogenies for species boundaries determination in the genusDiaporthe. PeerJ, 5, e3120. doi:10.7717/peerj.3120Lawrence, D. P., Travadon, R., & Baumgartner, K. (2015). Diversity of Diaporthe species associated with wood cankers of fruit and nut crops in northern California. Mycologia, 107(5), 926-940. doi:10.3852/14-353Gramaje, D., Agustí-Brisach, C., Pérez-Sierra, A., Moralejo, E., Olmo, D., Mostert, L., … Armengol, J. (2012). Fungal trunk pathogens associated with wood decay of almond trees on Mallorca (Spain). Persoonia - Molecular Phylogeny and Evolution of Fungi, 28(1), 1-13. doi:10.3767/003158512x626155GARDES, M., & BRUNS, T. D. (1993). ITS primers with enhanced specificity for basidiomycetes - application to the identification of mycorrhizae and rusts. Molecular Ecology, 2(2), 113-118. doi:10.1111/j.1365-294x.1993.tb00005.xTravadon, R., Lawrence, D. P., Rooney-Latham, S., Gubler, W. D., Wilcox, W. F., Rolshausen, P. E., & Baumgartner, K. (2015). Cadophora species associated with wood-decay of grapevine in North America. Fungal Biology, 119(1), 53-66. doi:10.1016/j.funbio.2014.11.002O’Donnell, K., & Cigelnik, E. (1997). Two Divergent Intragenomic rDNA ITS2 Types within a Monophyletic Lineage of the FungusFusariumAre Nonorthologous. Molecular Phylogenetics and Evolution, 7(1), 103-116. doi:10.1006/mpev.1996.0376Glass, N. L., & Donaldson, G. C. (1995). Development of primer sets designed for use with the PCR to amplify conserved genes from filamentous ascomycetes. Applied and Environmental Microbiology, 61(4), 1323-1330. doi:10.1128/aem.61.4.1323-1330.1995Weir, B. S., Johnston, P. R., & Damm, U. (2012). The Colletotrichum gloeosporioides species complex. Studies in Mycology, 73, 115-180. doi:10.3114/sim0011Udayanga, D., Castlebury, L. A., Rossman, A. Y., & Hyde, K. D. (2014). Species limits in Diaporthe: molecular re-assessment of D. citri, D. cytosporella, D. foeniculina and D. rudis. Persoonia - Molecular Phylogeny and Evolution of Fungi, 32(1), 83-101. doi:10.3767/003158514x679984Thompson, J. D., Higgins, D. G., & Gibson, T. J. (1994). CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Research, 22(22), 4673-4680. doi:10.1093/nar/22.22.4673Kumar, S., Stecher, G., Li, M., Knyaz, C., & Tamura, K. (2018). MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms. Molecular Biology and Evolution, 35(6), 1547-1549. doi:10.1093/molbev/msy096Vaidya, G., Lohman, D. J., & Meier, R. (2011). SequenceMatrix: concatenation software for the fast assembly of multi-gene datasets with character set and codon information. Cladistics, 27(2), 171-180. doi:10.1111/j.1096-0031.2010.00329.xRonquist, F., Teslenko, M., van der Mark, P., Ayres, D. L., Darling, A., Höhna, S., … Huelsenbeck, J. P. (2012). MrBayes 3.2: Efficient Bayesian Phylogenetic Inference and Model Choice Across a Large Model Space. Systematic Biology, 61(3), 539-542. doi:10.1093/sysbio/sys029Stamatakis, A. (2014). RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics, 30(9), 1312-1313. doi:10.1093/bioinformatics/btu033Felsenstein, J. (1985). CONFIDENCE LIMITS ON PHYLOGENIES: AN APPROACH USING THE BOOTSTRAP. Evolution, 39(4), 783-791. doi:10.1111/j.1558-5646.1985.tb00420.xDuthie, J. A. (1997). Models of the Response of Foliar Parasites to the Combined Effects of Temperature and Duration of Wetness. Phytopathology®, 87(11), 1088-1095. doi:10.1094/phyto.1997.87.11.1088Agricolae: Statistical Procedures for Agricultural Research. R Package Version 1.2-3http://CRAN.R-project.org/package=agricolaeVan Niekerk, J. M., Groenewald, J. Z., Farr, D. F., Fourie, P. H., Halleen, F., & Crous, P. W. (2005). Reassessment ofPhomopsisspecies on grapevines. Australasian Plant Pathology, 34(1), 27. doi:10.1071/ap04072Lesuthu, P., Mostert, L., Spies, C. F. J., Moyo, P., Regnier, T., & Halleen, F. (2019). Diaporthe nebulae sp. nov. and First Report of D. cynaroidis, D. novem, and D. serafiniae on Grapevines in South Africa. Plant Disease, 103(5), 808-817. doi:10.1094/pdis-03-18-0433-reGuarnaccia, V., Groenewald, J. Z., Woodhall, J., Armengol, J., Cinelli, T., Eichmeier, A., … Crous, P. W. (2018). Diaporthe diversity and pathogenicity revealed from a broad survey of grapevine diseases in Europe. Persoonia - Molecular Phylogeny and Evolution of Fungi, 40(1), 135-153. doi:10.3767/persoonia.2018.40.06Varjas, V., Vajna, L., Izsépi, F., Nagy, G., & Pájtli, É. (2017). First Report of Phomopsis amygdali Causing Twig Canker on Almond in Hungary. Plant Disease, 101(9), 1674. doi:10.1094/pdis-03-17-0365-pdnMichailides, T. J., & Thomidis, T. (2006). First Report of Phomopsis amygdali Causing Fruit Rot on Peaches in Greece. Plant Disease, 90(12), 1551-1551. doi:10.1094/pd-90-1551cLópez-Moral, A., Lovera, M., Raya, M. del C., Cortés-Cosano, N., Arquero, O., Trapero, A., & Agustí-Brisach, C. (2020). Etiology of Branch Dieback and Shoot Blight of English Walnut Caused by Botryosphaeriaceae and Diaporthe Species in Southern Spain. Plant Disease, 104(2), 533-550. doi:10.1094/pdis-03-19-0545-reAdaskaveg, J. E., Förster, H., & Connell, J. H. (1999). 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Almighty Cover Crops

Fungal pathogens are able to produce inoculum (spores) on plant debris present on the soil surface of vineyards. These spores can then reach plant surfaces and cause severe grapevine infections when environmental conditions are favourable. The capacity of plant diversity to increase the resistance of crops towards pests and invasive species is very well-known. For instance, Brassica spp. have been already investigated for their capacity to effectively suppress soil-borne inoculum of some causal agents of Black-foot disease in grapevines in vineyard soils. It may also have positive effect on the some dagger nematodes. Cover crops also stimulate the development of microbial communities such as arbuscular mycorrhizal fungi. Many management strategies have been developed against these important grapevine pathogens, but the effects of soil cover vegetation or organic mulching against spore dispersal, acting as a barrier, have been scarcely explored. Thus, in the BIOVINE project (www.biovine.eu) specific experiments were planned in order to verify the possibility of using cover crops: i) to control some relevant pathogens producing inoculum (spores) on plant debris present on the soil surface of vineyards; ii) to determine the presence of causal agents of Petri disease of grapevines on the roots of cover crops; iii) to promote mykorrhizal communities associated with grapevine roots; iv) to control arthropod pests (repellent of arthropods or attracting beneficials); v) to investigate Brassica plants effect on the soil-borne pest nematode Xiphinema index

First report of Fusarium wilt of albizia julibrissin caused by Fusarium oxysporum f.sp. perniciosum in Spain

[EN] In 2014, Albizia julibrissin trees located in gardens at Logroño municipality (La Rioja, Northern Spain) showed wilt symptoms, including defoliation, internal black streaks and, finally, tree death. Necrotic wood samples were surface disinfected for 1 min in 1.5% NaOCl, washed twice with sterile distilled water, plated onto potato dextrose agar (PDA) amended with streptomycin sulfate (0.5 g l¿1), and incubated at 25°C in the dark. Fusarium colonies were consistently isolated and transferred to Spezieller Nährstoffarmer agar (SNA). Ten days after incubation at 25oC, all isolates were identified as F. oxysporum, based on the presence of short monophialides, abundant microconidia produced in false heads (length 7.5 to 12.5 ¿m, average 9.20 ¿m) and chlamydospores, and sparse, usually three-septate, macroconidia (length 21.25 to 40 ¿m, average 29.70 ¿m) (Leslie and Summerell, 2006). The translation elongation factor 1-alpha gene (TEF) region of the isolates was amplified with primers EF1 and EF2 (O¿Donnell et al., 1998). Sequences showed 99% identity with a sequence of F. oxysporum f. sp. perniciosum (FJ985413). One sequence was deposited into GenBank (accession No. KU050689). Pathogenicity of isolates GIHF-019 and GIHF-021, was determined on one-year-old A. julibrissin plants grown in sterile peat moss, which were inoculated by watering the roots with 100 ml of a conidial suspension (106 conidia ml¿1). Plants were maintained at 25oC in a growth chamber under a photoperiod of 12 h. Two months after inoculation all inoculated plants wilted and the fungus was reisolated from them. To our knowledge, this is the first report of F. oxysporum f. sp. perniciosum in Spain.Berbegal Martínez, M.; Marín-Terrazas, M.; Ramón Albalat, A.; León Santana, M.; Armengol Fortí, J. (2016). First report of Fusarium wilt of albizia julibrissin caused by Fusarium oxysporum f.sp. perniciosum in Spain. JOURNAL OF PLANT PATHOLOGY. 98(3):694-694. doi:10.4454/JPP.V98I3.057S69469498

Evaluation of sown cover crops and spontaneous weed flora as a potential reservoir of black-foot pathogens in organic viticulture

International audience(1) Background. An extensive survey of grapevine-sown cover crops and spontaneous weed flora was conducted from 2019 to 2020 in organic vineyards in six European countries (France, Italy, Romania, Slovenia, Spain, Switzerland). Our main objective was to detect and identify the presence of Cylindrocarpon-like asexual morphs species associated with black-foot disease on their roots. (2) Methods. Fungal isolations from root fragments were performed on culture media. Cylindrocarpon-like asexual morph species were identified by analyzing the DNA sequence data of the histone H3 (his3) gene region. In all, 685 plants belonging to different botanical families and genera were analyzed. Cylindrocarpon-like asexual morphs were recovered from 68 plants (9.9% of the total) and approximately 0.97% of the plated root fragments. (3) Results. Three fungal species (Dactylonectria alcacerensis, Dactylonectria torresensis, Ilyonectria robusta) were identified. Dactylonectria torresensis was the most frequent, and was isolated from many cover crop species in all six countries. A principal component analysis with the vineyard variables showed that seasonal temperatures and organic matter soil content correlated positively with Cylindrocarpon-like asexual morphs incidence. (4) Conclusions. The presence of Cylindrocarpon-like asexual morphs on roots of cover crops suggests that they can potentially act as alternative hosts for long-term survival or to increase inoculum levels in vineyard soils