Grapevine Rootstocks for Oregon Vineyards, EM 8882 (Oregon State University Extension Service

Grafting, which involves combining two different varieties or species to form a plant with new characteristics, is a technique known from ancient times in tree fruit and grape production. It was, however, used in viticulture only for certain special cases: to change variety, increase vigor, or increase limestone tolerance. The principal reason for the increased use of grafting in viticulture was the phylloxera (Daktulosphaira vitifoliae) epidemic. Native to North America, phylloxera was inadvertently introduced into Europe around 1860. More than 4 million vineyard acres were destroyed by phylloxera before 1900. Leo Laliman, a French wine grape grower, is credited with the idea of grafting European grape vines, Vitis vinifera, onto rootstocks from Vitis species of North American origin. Because these species coevolved with phylloxera, they developed resistance mechanisms that still are not completely understood. Rootstocks have been bred from a number of Vitis species, especially V. berlandieri, V. riparia, and V. rupestris. Some common rootstocks and their parentage are shown in Figure 1 (page 2). Phylloxera was introduced into California at about the same time as its introduction into Europe. It has since been found in every major viticultural region of the world, with the exception of Chile and parts of Australia. In Oregon, phylloxera was first discovered at a commercial vineyard in 1990. It is estimated that the number of infested vineyards has doubled approximately every 2 years since then. In 2001, there were between 58 and 60 vineyards with confirmed phylloxera infestations. Because symptoms do not appear immediately, the actual number of infested vineyards probably is higher. Proper sanitation may reduce the risk of phylloxera infestation (see OSU Extension publication EC 1463), but it is no guarantee against its spread. The potential economic loss from phylloxera infestation is so great that planting on resistant rootstocks is recommended even in regions where phylloxera is not yet present. Prepared by Ray Shaffer, Tiago L. Sampaio (both of Department of Horticulture, Oregon State University); Jack Pinkerton, USDA-ARS, Corvallis; and M. Carmo Vasconcelos, Department of Horticulture, Oregon State University. Phylloxera as depicted by the Swiss biologist and enologist Dr. Otto von SchneiderOrelli (1880–1965). Enlarged 66x. Grapevine Rootstocks for Oregon Vineyards