Cherry leafroll virus

The Cherry leafroll virus (CLRV) is a significant plant pathogen classified within the Nepovirus genus, Secoviridae family. This RNA virus is known for its wide host range, infecting various deciduous trees and shrubs, posing a severe threat to commercial and ornamental horticulture.

This pathogen primarily targets stone fruits, including cherries, plums, and peaches, as well as walnut and birch trees. Clinical symptoms frequently manifest as downward leaf rolling, chlorotic ringspots, leaf senescence, necrotic lesions, and a general decline in canopy vigor, often leading to systemic necrosis and tree death.

The transmission biology of CLRV is multifaceted. It is effectively spread by soil-borne nematodes of the Xiphinema genus, which act as primary vectors. Furthermore, the virus is easily transmitted through infected seed lots, pollen transfer during flowering, and via grafting using scions from latently infected nursery stock.

Environmental conditions that favor the spread of the virus include high soil moisture, which supports the mobility and population density of nematode vectors. The virus is capable of persisting in the root systems of perennial hosts, ensuring its survival even in the absence of obvious symptoms in the upper canopy.

The economic impact of CLRV is profound, characterized by reduced fruit quality, stunted growth, and premature plant mortality, causing significant financial losses. Management strategies are focused on the following:

• Strict nursery hygiene and sourcing virus-indexed mother plants;
• Soil testing for nematode populations before establishing new orchards;
• Implementing appropriate nematicide treatments to control vector density;
• Prompt roguing and destruction of symptomatic trees to prevent further orchard contamination.