Tomato ringspot virus on grapevine: the first report of this virus in Jordan

After olives, grapevine (Vitis vinifera) is the second most important crop in Jordan. It is distributed throughout the country, covering an area of about 39,000 Ha (Anonymous, 2003). The phytosanitary status of Jordanian viticulture is largely unknown, with just a few published reports recording the occurrence of leaf roll, rugose wood and fan leaf (Bosci et al., 1995; Al-Tamimi et al., 1998). Several virus-like disease symptoms, including yellowing, leaf distortion, stunted growth and decline were observed during the last few years. In a survey conducted between March and July 2003, in the most important grapevines growing areas of Jordan, a total of 1088 leaf samples were collected from 60 commercial vineyards and 10 nurseries. The samples were individually tested for the presence of Tomato ringspot virus (ToRSV) by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), using a commercial kit from Bioreba (Bioreba AG, Reinach, Switzerland; ToRSV-PYBM), following the manufacturer's protocol. About 6.5% of the samples (71 out of 1088) tested positive for ToRSV, with substantial differences in incidence between different geographic regions. The infection rate was higher in commercial vineyards (7.1%) than in nurseries (2.7%). Mechanical inoculation with sap extracts from ToRSV-positive leaf samples induced necrotic, local lesions on Vigna unguicolata; chlorotic and necrotic local lesions followed by systemic mottling on Chenopodium amaranticolor and C. quinoa; and chlorotic or necrotic ringspots on the inoculated leaves of Cucumis sativus, followed by systemic chlorotic ringspots, tip necrosis and mottling. These symptoms are characteristic of ToRSV as described by Brunt et al. (1996). The presence of ToRSV was confirmed in the herbaceous indicators by DAS-ELISA. This report of ToRSV in grapevines is to the best of our knowledge the first report of ToRSV in Jordan.