GLRaV4

Grapevine leafroll-associated virus 4, commonly abbreviated as GLRaV-4, is a species of virus that infects grapevines. It belongs to the genus Ampelovirus within the family Closteroviridae. GLRaV-4 is one of several grapevine leafroll-associated viruses, which are known to cause a significant disease in grapevines called grapevine leafroll disease.

Grapevine leafroll disease is characterized by symptoms such as downward rolling of leaves, reddening of leaves in red grape varieties, and yellowing of leaves in white grape varieties. These symptoms can lead to reduced fruit quality and yield, impacting viticulture. GLRaV-4 is often found in mixed infections with other grapevine leafroll-associated viruses, making it challenging to attribute specific symptoms solely to GLRaV-4.

The virus is primarily transmitted through infected planting material, such as cuttings and rootstocks. It can also be spread by insect vectors, particularly mealybugs and scale insects, although the efficiency of vector transmission can vary. Management strategies for GLRaV-4 focus on using certified virus-free propagating material and controlling insect vectors to limit its spread within vineyards. Diagnosis of GLRaV-4 infection is typically done through molecular methods like RT-PCR.