Rupestris vein-associated virus

The Rupestris vein-associated virus (RGVaV) is a plant pathogen classified within the genus Ampelovirus of the Closteroviridae family. It is recognized as one of the viruses involved in the grapevine leafroll and degeneration complex. This pathogen specifically targets the phloem tissue of the grapevine, causing systemic infection.

The disease is characterized by chlorosis or clearing of the leaf veins, which is most prominent in indicator species such as Vitis rupestris. In many commercial grape cultivars, the virus may remain latent, showing no visible symptoms. Despite the lack of obvious signs, the virus significantly impacts the metabolic processes of the plant by disrupting the movement of nutrients and photosynthates.

Regarding its biology and cycle, the virus persists in infected vine tissues and is primarily disseminated through the use of infected propagation material (cuttings and rootstocks). Furthermore, mealybugs (family Pseudococcidae) act as biological vectors, transmitting the virus in a semi-persistent manner during their feeding process on host plants.

Environmental conditions that favor the proliferation of mealybug populations directly correlate with the spread of the virus. Warm, humid climates provide ideal conditions for vector activity, which facilitates the transmission of RGVaV between neighboring vines in a plantation. Poor sanitation in nurseries remains the most critical factor in the long-distance spread of this pathogen.

The economic impact is significant as infected vines exhibit decreased vigor, lower yields, and reduced quality of the grape harvest. Management strategies focus on preventive measures, such as the implementation of virus-indexing programs, the use of certified pathogen-tested planting material, and rigorous insect control programs to minimize vector pressure.