Grapevine leafroll disease

Grapevine leafroll disease is a widespread viral condition caused by a complex of viruses within the family Closteroviridae. These viruses primarily colonize the phloem tissues of the grapevine, disrupting the essential translocation of carbohydrates and nutrients throughout the plant structure.

The primary host for this pathogen is Vitis vinifera, although it can infect various rootstocks and hybrid cultivars. Once a vine is infected, it becomes a permanent source of inoculum, as the virus persists systemically in the plant tissues for the remainder of its productive lifespan.

Symptomatology includes the characteristic downward rolling of leaf margins, which typically begins in late summer. Leaves often exhibit chlorosis or reddening depending on the variety, while the interveinal tissues show distinct color changes, yet the primary veins remain green for a significant duration.

Transmission of the virus occurs via two main vectors: the propagation of infected scion wood and rootstock material, and the natural transmission facilitated by various species of mealybugs and soft scale insects. These vectors move the virus from symptomatic vines to healthy ones within the vineyard.

The economic impact of the disease is substantial, resulting in reduced yields, delayed fruit ripening, and significantly lower sugar accumulation in berries. Furthermore, the overall vigor of the grapevine is compromised, making infected vines more susceptible to abiotic stress and severe winters.

• Sourcing certified, virus-tested planting material for new vineyards.
• Implementing strict quarantine measures for any new vine introductions.
• Monitoring and managing populations of mealybugs and scale insects.
• Roguing and destroying symptomatic vines to prevent further spread.