GLRaV

GLRaV, short for Grapevine leafroll-associated virus, denotes a group of related plant viruses that cause grapevine leafroll disease. The viruses are primarily transmitted by mealybugs and soft scale insects and are largely confined to the phloem tissue of grapevines. Among the group, GLRaV-3 is the most widespread and economically significant, but several other GLRaV species have been identified in vineyards worldwide.

Symptoms of GLRaV infection vary by cultivar and environment. In red-berry cultivars, leaves typically show interveinal reddening or purpling and downward leaf roll; in white cultivars, yellowing and mild leaf distortion may occur. Infected vines often exhibit reduced vigor, lower berry sugar accumulation, and delayed ripening, contributing to yield and quality losses. Symptoms may resemble nutritional disorders or other grapevine diseases.

Detection and identification rely on laboratory assays. Serological tests such as ELISA can detect GLRaV antigens, while molecular methods like RT-PCR and sequencing identify specific GLRaV species in plant material. Virus indexing and certification programs also employ these tests to ensure clean propagation material.

Distribution and impact: GLRaV viruses are found in many grape-producing regions around the world. They are a major economic concern due to reductions in yield and fruit quality, which depend on vine age, cultivar, and the timing of infection.

Management: Control strategies focus on using certified virus-free planting stock, destruction of infected vines, and management of vector populations to reduce transmission. Vineyard sanitation, surveillance, and certification programs help limit spread and maintain vineyard health.