Identification and distribution of major viruses infecting grapevine in Morocco

In a survey during the growing seasons of 2011-2014, different viral symptoms were observed in grapevines, suggesting the presence of virus and virus-like diseases. A total of 1115 samples including 720 table and 395 wine grapes were collected from five Moroccan regions and tested by ELISA for the presence of ten different viruses. Moreover, 81 samples including some that were positive, negative and inconclusive in ELISA were confirmed in reverse transcription PCR. Among the tested grapevines, both wine (63.4%) and table grapes (60.3%) were readily infected whereas autochthonous table grapevine cultivars were less infected (31.1%). This survey revealed a high virus incidence but also the existence of healthy selection of all cultivars screened.