Phytosanitary challenges in belgian viticulture: first data from virome surveys and producer interviews

Belgian viticulture, driven by climate change and growing consumer interest, has expanded from 72 hectares in 2006 to 891 hectares in 2023. Despite lacking a long-established winemaking tradition, Belgium is creating new agroecosystems where winemakers explore diverse grape varieties and cultural techniques.
While this expansion presents exciting opportunities for wine enthusiasts, Belgian vineyards face faces significant phytosanitary challenges, particularly from viral and viroid pathogens known to severely impact grape yield and quality, such as Grapevine fanleaf virus (GFLV) and Grapevine leafroll-associated virus (GLRaV). Their presence in countries surrounding Belgium raises concerns about potential threats to the nascent Belgian wine industry.
Key questions arise: What is the current viral and viroid status of Belgian vineyards? How can we assess and mitigate the risks associated with these pathogens? What strategies can be implemented to protect this emerging crop?
To address these concerns, we conducted a comprehensive study involving a questionnaire and interviews with winegrowers. The responses from 88 growers described the typology of grapevine cultivation in Belgium related to the cultural practices, the origin of planting material, the diversity of cultivars, the perception of viral and phytoplasma threat… This survey was complemented by an extensive virome survey: 280 individuals symptomatic leaf samples and 687 symptomatic pool samples from over 50 grape varieties were sample in 86 vineyards. RNA was extracted and deep-sequenced, with confirmatory RT-PCR tests performed.
Analysis of symptomatic samples collected over two years identified 6 viruses and 4 viroids for the first time in Belgium, including GFLV. Asymptomatic samples analysis is ongoing. Preliminary risk assessment of the identified viruses will be further carried out, considering their potential impact on yield, quality, and vine longevity.
Further investigations will explore the relationship between the observed virome and various vineyard characteristics, including plant material origin and grape varieties cultivated. This comprehensive approach will will help identify potential pathways for pathogen introduction and support the development of targeted prevention strategies for Belgian viticulture.
Additionally, we initiated a training and awareness program on viral disease recognition and management to equip growers with the knowledge and skills to identify symptoms early, implement preventive measures, and manage infections effectively.
This research not only enhances our understanding of phytosanitary risks in Belgian viticulture but also contributes to developing effective crop protection strategies. By combining scientific analysis with practical education, we aim to safeguard this emerging industry and ensure its sustainable growth in the face of viral threats.