Managing Grapevine Trunk Diseases With Respect to Etiology and Epidemiology: Current Strategies and Future Prospects

Abstract

Fungal trunk diseases are some of the most destructive diseases of grapevine in all grape growing areas of the world. Management of GTDs has been intensively studied for decades with some great advances made in our understanding of the causal pathogens, their epidemiology, impact, and control. However, due to the breadth and complexity of the problem, no single effective control measure has been developed. Management of GTD must be holistic and integrated, with an interdisciplinary approach conducted in both nurseries and vineyards that integrates plant pathology, agronomy, viticulture, microbiology, epidemiology, biochemistry, physiology, and genetics. In this review, we identify a number of areas of future prospect for effective management of GTDs worldwide, which, if addressed, will provide a positive outlook on the longevity of vineyards in the future.

Evaluation of long‐term protection from nursery to vineyard provided by Trichoderma atroviride SC1 against fungal grapevine trunk pathogens

“…Despite efforts since the early 1990s to investigate the etiology and epidemiology of fungal grapevine trunk diseases (GTDs), they still represent a threat to viticulture, being responsible for important economic losses worldwide . Petri and black‐foot diseases are considered as the main GTDs affecting young vineyards, and Eutypa, Botryosphaeria and Phomopsis diebacks, and Esca and Grapevine Leaf Stripe diseases are the prevalent GTDs in adult vineyards …”

“…Altogether, these factors can explain why the management of GTDs is so difficult, but other additional aspects to consider are the cultural practices that favor fungal infection, such as high‐density spur‐pruned trellised vineyards, often mechanically pruned, which present a high number of pruning wounds and multiple additional infection opportunities, and the banning in the early 2000s of effective fungicides against GTDs, such as sodium arsenite and benzimidazoles …”

“…Grapevine producers are aware of the high likelihood of infection and substantial yield losses from GTD but, in general, they do not adopt management practices until disease symptoms appear in the vineyard, frequently when the vines are around 10 years old . Viticulturists are currently assuming that they must face GTDs throughout the entire life of the vine, integrating different control measures that can contribute to mitigate the economic impact of the diseases, but taking into account that complete eradication of these diseases is not possible . In this sense, the most important objectives to be covered by a GTD‐integrated management program are the improvement of the phytosanitary quality of the vines produced in the nursery and the prevention of infections of pruning wounds in the vineyard from the moment of planting …”

“…In nurseries, grapevine planting material is very prone to infection by GTD pathogens due to the large number of cuts and wounds made during the different steps in the propagation process . Gramaje and Di Marco conducted a wide questionnaire survey in grapevine nurseries in 13 European countries, Israel and Algeria, and identified a clear need for further research into the effects of treatments, including hot water treatment, biological control agents (BCAs) and other strategies such as ozonation, to reduce infection by GTD pathogens during grapevine propagation.…”

“…The importance of this pathway is enhanced by the long susceptibility period of grapevine pruning wounds, which can last up to 4–6 months, even with decreasing susceptibility . Different fungicides have been reported to be effective for pruning wound protection, but they have a short‐term efficacy and, in Europe, the current range of authorized active ingredients for this purpose is very limited . New chemical and physical protection formulations are under development, aiming to give long‐lasting protection against GTD infection, but BCAs preventively colonizing the fresh wounds may also serve this purpose …”