Plant Protection Central Research Institute, Yenimahalle, Ankara, Turkey Occurrence and Distribution of Grapevine Leafroll-associated Viruses 1, 2, 3 and 7 in Turkey B. B. Akbas Akbas ¸ 1 , B. B. Kunter Kunter 2 and and D. D. Ilhan Ilhan 1 AuthorsÕ addresses: 1 Plant Protection Central Research Institute, Gayret Mah, Fatih Sultan Mehmet Bulvarı No. 66, PO Box 49, 06172 Yenimahalle, Ankara, Turkey; 2 Faculty of Agriculture, Department of Horticulture, University of Ankara, 06110 Dıs¸kapı, Ankara, Turkey (correspondence to B. Akbas. E-mail: birol_akbas@zmmae.gov.tr, digdem_ilhan@hotmail.com) Received May 22, 2006; accepted September 12, 2006 Keywords: vineyards, spread, leafroll, central Anatolia region Abstract Grapevines in central Anatolia region of Turkey were surveyed for the prevalence of grapevine leafroll viruses. The field study and collection of samples were conducted in nine major grapevine-growing areas. Samples collected from 622 vines were tested for Grapevine leafroll-associated virus 1, 2, 3 and 7 (GLRaV-1, -2, -3 and -7). According to diagnostic tests and surveys, 27 of 41 cultivars and 95 of 622 samples (15.27%) were found to be infected at least one virus. GLRaV-1 (8.36%) was found to be the most frequently encountered virus associated with leaf- roll disease of grapes, followed by GLRaV-3 (5.78%), GLRAV-7 (3.86%) and GLRAV-2 (2.41%). Introduction Turkey is located in the centre of the domesticated area of Vitis vinifera. For that reason, Turkey has widespread cultivars and types of V. vinifera that serves as a great gene potential. Therefore, it has an important position among the other grape-producing countries. Grapevine culture in Turkey covers more than 520 000 ha mainly in Aegean, south-east Anatolia and central Anatolia region, respectively. Central Anatolia region (96 869 ha) encompasses more than 18% of cul- tivated area. Viral diseases remain one of the main threats to quality and yield of grapevine production. In the grape-growing countries of the world, so far more than 56 grapevine viruses and virus-like diseases have been described (Bonfiglioli et al., 2001) and almost 15 of them have been detected in Turkey. One of the most important viral diseases of grapevine is leafroll disease. Leafroll is considered to be the most economically important viral disease of grapevines, accounting for approximately 10–70% of the losses of grape produc- tion (Martelli, 1986; Goheen, 1988; Walker et al., 2004). Grapevine leafroll disease occurs wherever grapevines are grown and are associated with undesir- able viticultural effects which include delayed ripening of fruit, reduced yield, altered fruit pigmentation and reduced accumulation of sugar (Goheen, 1988). In this study, a survey was performed during 2000– 2003 in nine different grapevine-growing provinces in central Anatolia region against both virus-like symp- toms of leafroll and symptomless vines by means of enzyme-linked immunosorbent assay (ELISA) technique. Materials and Methods Sample collection The field study and collection of samples were con- ducted in 2000–2003 in commercial vineyards in the nine major grapevine-growing areas including Aksaray, Ankara, C¸ orum, Isparta, Karaman, Kırs¸ehir, Konya, Nevs¸ ehir and Yozgat. Samples were collected ran- domly to represent the area of grapes grown in the region. To obtain results with a high confidence of estimating the true proportion of the population that was infected, a total of 233 vineyards were examined. For testing, leaves including their petioles and canes were sampled from 622 individual vines. Middle and basal leaf samples were collected from near the bottom portion throughout the growing sea- son starting in May and ending in October. The leaf samples were collected three times throughout the season and each vineyard was sampled at the same time. In addition, 1-year-old cane samples were col- lected during the dormant period (winter). Leaves were collected separately from the several branches of plants and transported to the laboratory in moist paper towels on ice. The vines were randomly evalu- ated for both virus-like symptoms of leafroll and leafroll-free in each vineyard. The relationship between ELISA results and symptoms was studied by careful observation of leaf symptoms at every sampling date. www.blackwell-synergy.com J. Phytopathology 155, 122–124 (2007) Ó 2007 The Authors Journal compilation Ó 2007 Blackwell Verlag, Berlin