The Aegean region (western Turkey) is the center of table, raisin, and wine grape cultivation. During the 2012 growing season, wood canker symptoms were observed in vineyards in Manisa city. Symptoms adjacent to pruning wounds, including shoot dieback and wedge-shaped wood discolorations observed in cross section, were among the most prevalent symptoms of the vines. To identify the causal agents, symptomatic woody tissues were surface disinfested with 95% ethanol and flame-sterilized and the discolored outer bark was cut away. The internal tissues (0.5 cm2) were excised from cankers of vines and plated onto potato dextrose agar amended with tetracycline (0.01%) (PDA-tet). The most frequently isolated fungi, based on general growth pattern, speed of growth, and colony color, resembled species in the Botryosphaeriaceae family. According to morphological characteristics, four different groups have been identified based on visual discrimination. After DNA extraction, ribosomal DNA fragments (ITS1-5.8S-ITS2) (2) amplified with ITS4 and ITS5 primers were sequenced and sequences were compared with those deposited in NCBI GenBank database. Four different Botryosphaeriaceae isolates were identified, including Botryosphaeria dothidea (MBAi25AG), Diplodia seriata (MBAi23AG), Lasiodiplodia theobromae (MBAi28AG), and Neofusicoccum parvum (MBAi27AG) (Accession Nos. KF182329, KF182328, KF182331, and KF182330, respectively) with species nomenclature based on Crous et al. (1). Pathogenicity tests were conducted under greenhouse conditions (24°C, 16/8-h day/night, 70% RH) on 1-year-old own rooted grapevine (Vitis vinifera) cv. Sultana Seedless seedlings using one isolate from each of the Botryosphaeriaceae species specified above. Stems of grapevine seedlings were wounded by removing bark with 4-mm cork borer and fresh mycelial plugs were inoculated into the holes and covered with Parafilm. Sterile PDA plugs were placed into the wounds of control seedlings. Five vines were inoculated per isolate. The experiment was repeated twice. After 4 months of incubation, grapevine seedlings were examined for the extent of vascular discoloration and recovery of fungal isolates. Mean lesion lengths on wood tissues were 85.3, 17.2, 13.9, and 13.1 mm for N. parvum, B. dothidea, L. theobromae, and D. seriata, and 6.3 mm for control. Each fungal isolate was successfully re-isolated from inoculated seedlings to fulfill Koch's postulates. To our knowledge, this is the first report of multiple species in the Botryosphaeriaceae causing wood canker and dieback on grapevine in Turkey. These results are significant because Botryosphaeriaceae species are known causal agents of grapevine trunk disease worldwide (3). References: (1) P. W. Crous et al. Stud. Mycol. 55:235, 2006. (2) B. Slippers et al. Mycologia 96:83, 2004. (3) J. R. Urbez-Torres. Phytopathol. Mediterr. 50:S5, 2011.
Black-foot (BF) disease of grapevines in nurseries and young vineyards is caused by soilborne Cylindrocarpon-like asexual morphs. They can be found both in symptomatic and asymptomatic vines, being spread to new grape growing areas during vineyard establishment. In this study, 42 grapevine nurseries located in different geographical regions in Turkiye were surveyed in 2021 to determine the presence of BF pathogens on asymptomatic marketable plants.Black-foot fungi were isolated from the roots or basal ends of asymptomatic dormant vines in 39 of them (92.9%). The percentage of isolation of BF pathogens ranged from 1.4 to 51.4% (average 18.4%). Seven species: Cylindrodendrum alicantinum, Cylindrocladiella peruviana, Dactylonectria macrodidyma, D. novozelandica, D. torresensis, Ilyonectria liriodendri, and I.2 robusta were identified based on DNA sequencing of histone H3 gene and phylogenetic analyses, D. torresensis being the most frequent. From these species Ca. peruviana, D. novozelandica and I. robusta were detected for the first time on grapevines in Turkiye. Pathogenicity tests on 1103P rootstock cuttings revealed that all species significantly decreased root biomass and increased root disease severity index, when compared with the non-inoculated control, D. novozelandica being the most virulent. Pathogenicity of Cm. alicantinum to grapevine was confirmed for the first time, thus this species should be included as causal agent of BF of grapevines. These findings point out that BF pathogens are highly prevalent in asymptomatic nursery produced grapevines and could represent a serious threat for Turkish viticulture.
Powdery mildew, dead arm and vineyard downy mildew diseases are frequently seen in the vineyards in the Gediz River Basin, West Anatolia of Turkey. These diseases can be detected early using artificial intelligence (AI)–based systems that can contribute to crop yields and also reduce the labour of the farmer and the amount of pesticides used. This article presents a dataset – namely, Hermos – for use in such AI-based systems. Hermos contains four classes of grape leaf images: leaves with powdery mildew, leaves with dead arm, leaves with downy mildew and healthy leaves. We have currently 492 images and 13,913 labels in the dataset. We have published Hermos in the Linked Open Data (LOD) cloud in order to make it easier for consumers to access, process and manipulate the data.
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