About Rootstocks

Rootstocks: Protection against phylloxera

Grape phylloxera is regarded as the world's worst grapevine pest. Since the mid to late 19th century it has devastated vineyards across Europe, North America, New Zealand, South Africa and parts of South America and Australia. Productive viticulture cannot normally continue on own-rooted vines following an infestation by phylloxera. The only effective long-term management strategy for controlling phylloxera is a replanting program using vines grafted on phylloxera tolerant rootstocks.

Phylloxera tolerant rootstocks are bred from grapevines native to North America known as American vitis species. These particular species evolved in the presence of the phylloxera and so developed tolerance mechanisms that allowed them to continue to flourish in the presence of the insect. The mechanism by which tolerance occurs is mainly by the formation of a layer of cork tissue around the root lesion, which limits the spread of decay, and, to a lesser extent, resistance by repulsion.

Rootstock use in South Australia

Unlike other grapegrowing regions in the rest of the world, South Australia and indeed most of Australia are free of phylloxera. This has meant that the use of rootstocks has not been essential. Currently rootstocks account for 12,872 ha (18%) of plantings in South Australia, mainly in the Riverland (7,900 ha or 11%). However, since 2000, 28% of new plantings have been on rootstocks, indicating the industy's increased awareness of the risk of phylloxera and the other benefits associated with planting on rootstocks. For information on your region's rootstock planting statistics click here (8 Kb PDF file)

Traditionally rootstocks have also been used in Australia to overcome another soil-borne pest: nematodes. More recently it has been recognised that rootstocks are able to provide a number of other benefits apart from their tolerance/resistance to phylloxera and nematodes. These benefits are discussed in the next section.