Chapter 20

Managing Vineyard Diseases

Viral Pathogens

Grape Leafroll Disease

Grape leafroll disease is one of the most important virus diseases of grapevines. It occurs in all the major grape-growing regions of the world. Grape leafroll disease can affect all native and V. vinifera varieties, hybrids, and rootstocks, although symptoms are not expressed on all infected vines.

Symptoms

Symptoms with dark-skinned berries can be recognized by red and reddish-purple tints in the interveinal areas on mature leaves in late summer and fall. These discolorations may coalesce with time, leading to reddish-purple color of interveinal areas and green tissue near the main veins.

Transmission

Long distance spread occurs primarily by movement of propagation material from infected plants.

Disease Management

Cultural Practices: Control of the disease is relatively simple—removal of the infected vines. Other than that growers should plant healthy certified stock or known to be virus-free.

Chemicals: Chemical control is not used against virus diseases.

Click on the following topics for more information on managing vineyard diseases.