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UCP 1 - Vineyard | FRANCE

Grapevine Leafroll Disease (GLRaV-1 & GLRaV-3 - Virus) & Blackwood Yellows (Candidatus Phytoplasma solani - Bacterium)

Pest Challenges

Grapevine Leafroll Disease (GLD) is a viral infection caused by Grapevine Leafroll-associated Virus (GLRaV), primarily spread by mealybugs. GLD symptoms vary depending on the GLRaV species, with GLRaV-1 and GLRaV-3 being most severe and targeted for regulatory detection. Manifestations include foliage discoloration, reducing photosynthesis and yield by 15 to 30%, with severe cases facing up to a 60% loss. Infected vines show reduced vigor and struggle to recover from winter injury due to depleted carbohydrate stores. Harvest quality is compromised, with late and irregular ripening, decreased sugar content, increased acidity, and poor polyphenol levels. GLD poses significant economic challenges globally, often leading to premature vine uprooting due to reduced profitability. Additionally, contaminated nursery plots hinder plant production. Identifying GLD is difficult due to symptom variability across grapevine varieties and environmental factors.

Blackwood Yellows (BY) is a grapevine disease caused by Candidatus Phytoplasma solani, an RNQP bacterium primarily transmitted by root-feeding Fulgores like Hyalesthes obsoletus in France. BY induces sterility in symptomatic branches, characterized by leaf discoloration and lack of lignification, directly leading to crop losses and economic strain on vineyards. Quantitative models suggest BY can diminish wine and table grape production in the European Union by 4-8%. Additionally, BY complicates disease management by masking the detection of other yellow diseases like Flavescence Dorée, escalating survey costs and necessitating extensive efforts for accurate assessment. Misdiagnosis due to BY presence may result in ineffective control measures, prolonging its impact on vineyard health and productivity. Some French regions allocate substantial funds, exceeding 600,000 euros annually, to combat BY, highlighting the urgent need for enhanced detection strategies and effective control measures.

Region Challenges

The vineyard is located in the Alsace region covering a surface of 15,000 ha with a production of 1 million hectoliter/year. Mostly quality white and sparkling wines are produced in specifications Protected Designation of Origin (PDO) Alsace.

In Alsace vineyards, managing Grapevine Leafroll Disease (GLD) and Blackwood Yellows (BY) is critical for sustaining vine health, productivity, and the viability of the wine industry. Concerns about GLD require controls against GLRaV-1 and -3 in mother vines, which threaten the supply of planting material for vineyard renewal in Alsace.

UCP plan

For the French UCP in the Alsace region (vineyard), a minimum of three different farms will be selected in diverse zones, in order to investigate potential presence and outbreak level of the pest