Fungal trunk pathogens in the grapevine propagation process-potential inoculum sources, detection, identification, management (GTD)

Symptoms of young grapevine decline and failure of planting material have plagued the raisin, table, and wine grape industry since the 1990s. Evaluation of declining young vineyards has revealed that many factors are involved in the poor performance of vines. Fungal trunk pathogens have been extensively investigated and are now considered one of the major causes of this syndrome. Black-foot and Petri diseases, and species of Botryosphaeriaceae, all contribute to young grapevine decline, reducing productivity and longevity, thereby causing considerable economic loss to the industry. Subsequent investigations have led to the conclusion that planting material used in young vineyards is already infected, either systemically from infected mother vines or by contamination during the propagation process. In this review, the causal organisms and their associated symptoms are discussed. Specific attention is given to the grapevine propagating process, the potential inoculum sources, and the detection tools being developed to facilitate rapid identification of these pathogens. The review also evaluates the currently known management strategies applied in nurseries. Lastly, an overview is given of how to minimize the economic impact of these pathogens and to improve the quality of planting material.