Nematode Pests of Grapevine

Abstract

In South Africa, plant-parasitic nematodes are common in vineyards and are often associated with poor growth of the vines, relatively short internodes and comparatively small berry bunches. Such damage results in an overall yield loss of about 15 %. Soils in most vineyards are infested with at least four plant-parasitic nematode genera, of which the economically most important are Meloidogyne, Pratylenchus, Xiphinema and Criconemoides. Of note is that Xiphinema index has been shown to spread Grapevine fanleaf virus. Various management options for limiting the damage caused by nematode pests are outlined. Vines are usually planted in old vineyards or old stone fruit orchards in soil that is infested with large populations of plant-parasitic nematodes. In such cases, nematode-free plant material, a tolerant or resistant rootstock and the application of a pre- or post-plant nematicide treatment are recommended. Although resistant rootstocks are available, their use has declined in favour of rootstocks that are more compatible with the production of high-quality wines on the varied soils but that are more susceptible. The variable responses of grapevine to nematicide treatment, which is a common practice in local orchards, make their continued use questionable.