Transmission of grapevine Roditis leaf discolouration‐associated virus by the vine mealybug, <i>Planococcus ficus</i> (Signoret) in Turkey

ABSTRACT Grapevine Roditis leaf discolouration‐associated virus (GRLDaV) is from Badnavirus decoloratiovitis species, which is a member of the genus Badnavirus, associated with Roditis leaf discolouration disease. Although mealybug transmission of GRLDaV by Planococcus ficus has been demonstrated elsewhere, its role in the transmission has not been shown in different grapevine varieties, isolates, acquisition periods (AP) and inoculation periods (IP). Individiual P. ficus was collected from a vineyard in Adana, Turkey and used for insect culture establishment for the transmission studies. Virus transmission experiments to the Vitis vinifera cv. Yalova Incisi via P. ficus was carried out using a local GRLDaV isolate by applying AP‐IP for 24, 48 h or 72 h. The virus was transmitted by P. ficus in all AP‐IP trials (100%, 60%, and 20% of recipient vines infected after 24, 48 h, and 72 h, respectively). GRLDaV was first detected in the recipient grapevines four weeks after transmission. The results showed that P. ficus transmitted GRLDaV in a semipersistent manner. All the virus infected vines in the experiment showed initial leaf symptoms of yellow vein banding and/or discolouration, followed by yellow and/or reddish discolouration of the leaves in late summer, as observed in GRLDaV‐infected vines in the field.