WINETECH Technical Yearbook 2020

PHOTO 7. Collect lignified cane material sep- arately from the scion and rootstock of lea- froll-infected vines, perform RNA extraction on the phloem tissue and test for GLRaV-3 by RT-PCR separately in both components.

PHOTO 3. Grapevine leafroll disease is diffi- cult to detect in white cultivars. In the picture above, Chardonnay, which is one of the white cultivars that shows the disease best, displays the symptoms which gave grapevine leafroll disease its name.

PHOTO 6. Vines were selected where the sci- on (red cultivars) displayed clear symptoms of grapevine leafroll disease, but where vigorous, lignified Richter 99 rootstocks were present.

PHOTO 4. Grafting of the Vitis vinifera sci- on onto a rootstock via omega grafting, as a means of managing the effect of phylloxera.

PHOTO 8. An abandoned vineyard where the Richter 99 rootstock had not been removed over a number of seasons.

PHOTO 5. Rootstocks do not show symptoms of grapevine leafroll disease.

WINETECH TECHNICAL YEARBOOK 2020 14