Grapevine leafroll disease

The causative agent of this disease is the Ampelovirus tetravitis, a member of the Closteroviridae family. It is a persistent, phloem-limited virus that systematically infects the grapevine, disrupting the translocation of carbohydrates and other nutrients, which is vital for the physiological processes of the plant.

This virus primarily infects grapevines of the species Vitis vinifera and their hybrids. It is considered one of the most economically damaging viral diseases in viticulture globally, as it persists within the plant for its entire life cycle, causing chronic physiological stress.

The characteristic symptoms include the downward curling of leaves, often accompanied by interveinal chlorosis (in white varieties) or reddening (in red varieties). While the leaves change color and shape, the primary veins usually remain green. Affected vines show reduced vigor, stunted shoots, and a significant decrease in berry quality.

The spread of the virus occurs primarily through the propagation of infected nursery stock and by sap-sucking insects. Mealybugs (Pseudococcidae) and scale insects are the most common vectors, acquiring the virus during feeding and transmitting it to healthy vines. Human activity, such as grafting with infected scions, is also a major driver of spread.

The economic impact of Ampelovirus tetravitis is severe, leading to significant yield losses and delayed maturation of grapes. The reduced accumulation of sugar and anthocyanins directly affects wine quality. Furthermore, infected vines are less capable of accumulating starch reserves, making them highly susceptible to winter damage.

• Planting of certified virus-free rootstocks and scions.
• Integrated pest management (IPM) to control mealybug and scale insect populations.
• Rigorous monitoring and rogueing of symptomatic vines in the vineyard.
• Sterilization of pruning tools to prevent mechanical transmission of viral particles.