Fusarium species are agriculturally important fungi with a broad host range and can be found as endophytic, pathogenic, or opportunistic parasites in many crop plants. This study aimed to identify Fusarium species in bare-rooted, dormant plants in Turkish grapevine nurseries using molecular identification methods and assess their pathogenicity. Asymptomatic dormant plants were sampled from grapevine nurseries (43) in different regions of the country, and fungi were isolated from plant roots and internal basal tissues. The Fusarium strains were identified by performing gene sequencing (TEF1-α, RPB2) and phylogenetic analyses. Pathogenicity tests were carried out by inoculating mycelial agar pieces of strains onto the stem or conidial suspensions into the rhizosphere of vines (1103 Paulsen rootstock). Laboratory tests revealed that Fusarium species were highly prevalent in Turkish grapevine nurseries (41 out of 43). Gene sequencing and phylogenetic analyses unraveled that 12 Fusarium species (F. annulatum, F. brachygibbosum, F. clavum, F. curvatum, F. falciforme, F. fredkrugeri, F. glycines, F. nanum, F. nematophilum, F. nirenbergiae, F. solani, and Fusarium spp.) existed in the ready-to-sale plants. Some of these species (F. annulatum, F. curvatum and F. nirenbergiae) consistently caused wood necrosis of seedling stems, rotting of the basal zone and roots, and reduced root biomass. Although the other nine species also caused some root rot and root reduction, their virulence was not as severe as the pathogenic ones, and they were considered opportunistic parasites or endophytic species. This study suggests that Fusarium species might play an important role in root-basal rot, wood canker symptoms, and young vine decline in Turkish grapevine nurseries and that these species need to be considered for healthy seedling production.

Good health of grapevine plants is important for productivity and sustainability of newly established vineyards, and accurate detection of bacterial and fungal pathogens is a prerequisite for managing the diseases they cause in nurseries. This study screened marketable, bare-rooted grapevine plants, obtained from different geographical regions of Türkiye, for fungal pathogens associated with grapevine trunk diseases (GTDs). In 2021, 43 grapevine nurseries located in eight provinces were surveyed to reveal the status of GTD pathogens on asymptomatic marketable plants. Fungal pathogens isolated from the roots and basal parts of asymptomatic dormant grapevines were identified using with morphological characteristics and molecular markers, and were subjected to pathogenicity tests. Six species; Cytospora viticola, Diaporthe ampelina, Diplodia seriata, Lasiodiplodia brasiliensis, Neofusicoccum parvum, and Truncatella angustata (associated with dieback), and six species; Cadophora ferruginea, Cadophora luteo-olivacea, Cadophora malorum, Phaeoacremonium minimum, Phaeoacremonium tuscanicum and Phaeomoniella chlamydospora (associated with Petri disease) were identified based on DNA sequencing of ITS and TEF1-α genes. GTD pathogens were detected in 12 and 14 of the 43 nurseries, respectively. Pathogenicity tests on 1103P vines revealed that all species were pathogenic (N. parvum and C. luteo-olivacea being the most virulent), and caused significant wood necroses when compared to non-inoculated experimental controls. This is the first report of C. ferruginea, C. malorum, L. brasiliensis, and P. tuscanicum associated with GTDs in Türkiye.

Black foot disease, which is mainly caused by Ilyonectria Chaverri & Salgado and Dactylonectria L. Lombard & Crous species, causes serious destruction in most of the wine and grape producing regions of the world, particularly in nurseries and young vineyards. The aim of this research was to evaluate the present situation of black foot disease in grapevine nurseries (Vitis Vinifera L.), to identify its potential agents at morphological and molecular levels and to develop a control strategy against isolates found as the major virulent ones in pathogenicity tests. This study also represents the first attempt to control black foot disease in grapevine saplings in Turkey. Preliminary surveys were carried out in 21 grapevine nurseries in the Aegean Region during 2019 growing season. Black foot species obtained from vine saplings were identified as Ilyonectria liriodendri (Halleen, Rego & Crous), Dactylonectria macrodidyma (Halleen, Schroers & Crous) and D. torresensis (A. Cabral, Rego & Crous), using morphological and molecular methods. The pathogenicity studies revealed that the most virulent isolates belonged to I. liriodendri. Twelve chemical and one biological fungicides were screened in vitro for mycelial inhibition of I. liriodendri isolates. The experiments were performed in three replicates for each of the chemical fungicides. Sterile distilled water, instead of fungicide solution, was used for control trials. Mixtures of cyprodinil + fludioxonil, thiabendazole + fludioxonil + metalaxyl–m + azoxystrobin and azoxystrobin + metalaxyl-m + fludioxonil were the most effective chemical fungicides tested in mycelial inhibition of I. liriodendri isolates. Chemical fungicides mixtures of boscalid + kresoxim-methyl, promocarb hydrochloride (HCL) + fosetyl-al, azoxystrobin + difenoconazole, fludioxonil + metalaxyl–m and individual fungicides; cyprodinil, fluoxapyroxad, hymexazole, fenhexamid and 8-hydroxyquinoline sulphate were not effective on mycelial inhibition. Biocontrol activity of Trichoderma harzianum Rifai KRL-AG2 strain against I. liriodendri was evaluated. The experiment was performed in four replicates for each isolate. Petri dishes with only I. liriodendri mycelial discs used as controls. Treatment with Trichoderma harzianum Rifai KRL-AG2 strain provided 60.1% to 80.6% inhibition against I. liriodendri isolates. The most effective fungicides tested in vitro were evaluated in 2020 and 2021 under controlled conditions against possible infections of I. liriodendri during the rooting process of 1103 Paulsen grapevine rootstocks. Mixtures of thiabendazol + fludioxonil + metalaxyl–m + azoxystrobin and cyprodinil + fludioxonil were the most effective fungicides in the experiments conducted in 2020 and 2021, followed by azoxystrobin + metalaxyl-m + fludioxonil and Trichoderma harzianum Rifai KRL-AG2 strain.

The aim of this study was to realize the molecular identification of Diplodia seriata De Not., a member of the Botryosphaericea family, isolated from 2-10 years old vines in vineyards showing symptoms of dieback disease. The susceptibility of the pathogen against the fungicides with the fosetyl-Al+triadimenol, azoxystorbin+difecanozole, fludioxanil+cyprodinil, metrafenone, fluopyram+tebuconazole combinations were evaluated. The isolates obtained from the root and crown parts of the vine samples were identified as D. seriata according to the morphological and molecular methods. In molecular identification, the ITS (Internal Transcribed Spacer) and TUB2 (β-tubulin) gene regions of the isolates were amplified by Real-Time PCR and the nucleotide sequences were obtained in these gene regions. After using the MEGA 7 software, ITS and TUB2 sequences were aligned and a combined phylogenetic tree was made. It has been molecularly confirmed that the D. seriata isolate has a 100% similarity index with Diplodia species according to the phylogenetic analyses. The mean effective concentration (EC50) values of fungicides used with different concentrations (0, 1, 3, 10, 30, 50, 100 μL mL-1) were determined by Probit analysis. Cyprodinil + fludioxonil showed the highest efficacy (100%) at a concentration of 1 μL mL-1. According to EC50 values, cyprodinil + fludioxonil (0.001 μL mL-1) was recorded as the most effective fungicide followed by fluopyram + tebuconazole (0.520 μL mL-1) and, azoxystrobin + difenoconazole (2.958 μL mL-1), respectively.

Fusarium species are agriculturally important fungi with a broad host range and can be found as endophytic, pathogenic, or opportunistic parasites in many crop plants. This study aimed to identify Fusarium species in bare-rooted, dormant plants in Turkish grapevine nurseries using molecular identification methods and assess their pathogenicity. Asymptomatic dormant plants were sampled from grapevine nurseries (43) in different regions of the country, and fungi were isolated from plant roots and internal basal tissues. The Fusarium isolates were identified by performing gene sequencing (TEF1-α, RPB2) and phylogenetic analyses. Pathogenicity tests were carried out by inoculating mycelial agar pieces of isolates onto the stem or conidial suspensions into the rhizosphere of vines (1103 Paulsen rootstock). Laboratory tests revealed that Fusarium species were highly prevalent in Turkish grapevine nurseries (41 out of 43). Gene sequencing and phylogenetic analyses unraveled that 12 Fusarium species (F. annulatum, F. brachygibbosum, F. clavum, F. curvatum, F. falciforme, F. fredkrugeri, F. glycines, F. nanum, F. nematophilum, F. nirenbergiae, F. solani, and Fusarium spp.) existed in the ready-to-sale plants. Some of these species (F. annulatum, F. curvatum and F. nirenbergiae) consistently caused wood necrosis of seedling stems, rotting of the basal zone and roots, and reduced root biomass. Although the other nine species also caused some root rot and root reduction, their virulence was not as severe as the pathogenic ones, and they were considered opportunistic parasites or endophytic species. This study is the first detailed investigation of Fusarium species in grapevine nurseries in Türkiye and emphasizes the need to consider pathogenic species in producing healthy grapevine seedlings.