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Öğe Determination of the races of Plasmopara halstedii (Farl.) Berl. & de Toni, the causal agent of sunflower downy mildew in Turkey and reactions of some commercial sunflower varieties against these races(Zirai Mücadele Merkez Araştırma Enstitüsü, 2019) Oksal, Erçin; Maden, SalihDowny mildew of sunflower caused by Plasmopara halstedii, is the most important disease of sunflower throughout the world including Turkey. Within the scope of the study, surveys were performed in Tekirdağ, Edirne, Kırklareli, Ankara, Bursa, Samsun, Tokat and Adana provinces where sunflower is widely grown in the period of 2009-2015. During the surveys, sixty-five P. halstedii isolates were obtained and purified. Using the race differentials set, nine races of the pathogen (100, 102, 110, 300, 500, 502, 510, 702 and 712) were determined. All races determined are first records for Turkey, whereas the races 102, 510 and 110 are the first record for the world. Almost 71% percent of the races were belonged to race 100. The reactions of 19 commercial sunflower cultivars against P. halstedii were determined by using isolates representing different races of downy mildew. None of the commercial sunflower cultivars showed resistance against all the races of P. halstedii at the same time. Among varieties tested LG5580 was found to be resistant to four races, whereas Sanay MR, Sanbro MR, LG540HO, and Sanbro varieties were found to be 3,3,2 and 1 races, respectively.Öğe First report of canker and dieback caused by Cytospora viticola on grapevine in Turkey(Springer, 2020) Oksal, Erçin; Çelik, Yusuf; Özer, Göksel; OksaCytospora species are seriously damaging pathogens causing canker and dieback on several woody hosts of agronomic, forestry, and ornamental importance. In June 2018, symptoms of trunk diseases on plants including death of branches, diagnostic chlorotic foliage with necrotic margins, and brownish discoloration inside the wood were observed with an incidence of up to 10% in grapevine (Vitis vinifera L.) fields in the Arapgir district of Malatya. To obtain fungal isolates, necrotic woody tissues were surface disinfected with 1% sodium hypochlorite for 60 s and twice rinsed, air dried, and placed onto 2% malt extract agar (MEA) (Merck, Darmstadt, Germany) amended with tetracycline (0.01%). Petri dishes were incubated at 25 °C in the dark for three weeks. A total of 14 isolates were obtained and identified as Cytospora viticola D.P. Lawr., Travadon & Pouzoulet based on morphological characteristics of white to light straw-coloured colony, dark-brown pycnidia measured 947–1618 ?m in diameter (n?=?20) and pycnidiospores were hyaline, allantoid, aseptate, and ranged from 4.2 to 6.1 ?m in length × 1.1 to 1.8 ?m in width (n?=?50) on MEA (Lawrence et al. 2017). No teleomorphic stage was observed. DNA sequences of Internal Transcribed Spacer (ITS) region, part of the ?-tubulin gene (BT2), and part of the translation elongation factor 1-? gene (EF1-?) from a reference grapevine isolate of C. viticola (Arp2-D) were amplified, sequenced, and deposited in the GenBank database (MK706295, MK715441, and MK715442, respectively). Resultant sequences showed 99–100% identity with those of C. viticola isolate Cyt21 (ITS: KX256244, BT2: KX256223, EF1-?: KX256265). Pathogenicity assays were conducted using disinfected 2-year-old twigs of V. vinifera cv. Köhnü plants inoculated by placing 5-mm-diameter mycelial plugs excised from ten-day colonies into wounds made by removing the bark with a cork borer, while the control plants were inoculated with sterile agar plugs. Inoculated plants were then incubated at 25 °C in a 12-h photoperiod. After 21 days, symptoms of inner bark discoloration were observed in vascular and cortex tissues from which the pathogen was re-isolated successfully to fulfill Koch’s postulates. No symptoms were observed in the control plants. To our knowledge, this is the first report of canker and dieback caused by C. viticola on grapevine in Turkey; the pathogen has been currently reported in the USA and Canada (Lawrence et al. 2017; Farr and Rossman 2019).Öğe First report of Neoscytalidium dimidiatum causing shoot blight, dieback and canker of apricot in Turkey(Springer, 2020) Oksal, Erçin; Yiğit, Talip; Özer, NiyaziTurkey is the largest apricot (Prunus armeniaca L.) producing country worldwide with almost 17 million trees producing fruits (TUIK 2019). In June 2018, shoot blight, branch dieback and canker symptoms were observed on about 9% apricot trees in the orchards examined in Malatya province (Turkey), which is alone responsible for 15.8% of world production of apricots.Öğe In Vitro Efficiency of Some Fungicides Against Neoscytalı̇dı̇um dı̇mı̇dı̇atum (Penz.) Crous and Slippers Causing Sudden Shoot Dry on Apricot Trees(Turkish Science and Technology Publishing (TURSTEP), 2021) Sür, Aysun Eraslan; Oksal, ErçinTurkey is known as a top producer and exporter of apricots, both fresh and dried. More than half of Turkey's apricot production is provided by Malatya province. There are many pests and diseases affecting apricots in addition to climatic factors such as frost and hail. Partial shoot drying and sudden drying in apricot orchards have increased in recent years. In this study, it was aimed to determine the chemical control possibilities of Neoscytalidium dimidiatum (Penz.) Crous &Slippers, which is one of the fungal agents that cause partial branch drying and sudden drying in apricot orchards in Malatya province by in vitro studies. For this purpose, Kale 4-C isolate of N. dimidiatum collected from Malatya in a previous study was used. Mycelial growth of N. dimidiatum Kale 4-C isolate in PDA were observed in 0 (control), 0.01, 0.03, 0.1, 1, 3, 10, 30 ve 100 ?g/mL concentrations of Azoxystrobin 250g/L, Trifloxystrobin %50, Tebuconazole %25, Floupyram 200 g/L+Tebuconazole 200 g/L, Cyprodinil+Fludioxonil %37.5+25, %70 Thiophanate-Methyl and 400 g/L Phosphorous acide fungicides applications. As a result of the study, Floupyram 200g/L+Tebuconazole 200g/L ve Cyprodinil+Fludioxonil %37.5+25 fungicides effectively inhibited the mycelial growth of the fungus.Öğe Neoscytalidium dimidiatum causes canker and dieback on grapevine in Turkey(Springer, 2019) Oksal, ErçinIn July 2018, a canker and dieback disease was observed with an incidence of up to 10% in five vineyards in Malatya province. The aim of this study was to characterise the causal organism by morphological and molecular characteristics. Based on macro- and micro-morphological features of the colonies and sequencing of the beta-tubulin gene, the translation elongation factor 1-alpha gene, the large subunit of rDNA gene, and the internal transcribed spacer region of rDNA, the pathogen was identified Neoscytalidium dimidiatum. Koch's postulates confirmed N. dimidiatum as a causal agent of symptoms associated with canker and dieback on grapevine plants in Turkey.Öğe Prevalence, molecular characterization, and variety reactions of Neoscytalidium novaehollandiae on mulberries in Turkey(AcademicPres, 2022) Oksal, Erçinurkey is one of noteworthy countries for both fruit genetic resources and amount of fruit production in the world. Mulberry is cultivated throughout Turkey, most commonly in Central, Northeast and Southeast Anatolia. Mulberry has a great market potential thanks to its fresh consumption and usage of processed food products. In June 2019, a disease was observed causing deaths in shoots and branches on mulberry trees in Malatya province of Turkey. The causative agent of the disease was identified as Neoscytalidium novaehollandiae according to morphological characteristics and sequencing of TEF 1-a gene (Accession no. MT362602 and MT362603), ITS (Accession no. MT195554 and MT195555) and LSU (Accession no. MT195552 and MT195553). Based on the concatenated sequences of the ITS, TEF 1-a, and LSU, a phylogenetic tree was built using Bayesian analysis. Reactions of nine mulberry cultivars against the disease ('Ulukale', Ayas/, 'Ichinose', 'Poser', 'Kenmochi', Arapgir', 'San as/, 'Horum' and 'Istanbul') inoculated with Malatya isolate of A! novaehollandiae were evaluated under growth chamber conditions. All-mulberry cultivars artificially inoculated with N. novaehollandiae isolate exhibited severe necrosis symptoms on woody tissues of tested plants. It was confirmed that N. novaehollandiae is a fungal pathogen associated with dieback and canker on mulberry trees in Turkey for the first time. New mulberry plantations could be endangered by this emerging new disease.
