How to Manage Pests

Pests in Gardens and Landscapes

Viruses

Several different virus diseases may occur in grapes. Three common viruses are leafroll, corky bark, and fanleaf degeneration. Leaves affected by leafroll turn red or yellow, depending on whether the variety produces red- or green-colored fruit. Leaves roll and have distinct green vein banding. Corky bark symptoms resemble those of leafroll, but their effect is more pronounced. Corky bark leaves roll downward and turn uniformly reddish. Fanleaf degeneration causes new growth to be dwarfed or mottled and deformed. Leaves may show a mosaic pattern or vein banding.

Solutions

The only effective control of any grape virus disease is to ensure that healthy propagating material from virus-tested stock is used to plant in home gardens.

Healthy and virus infected leaves
Healthy and virus infected leaves
Fanleaf degeneration
Fanleaf degeneration
Leafroll
Leafroll on red grape variety
Leafroll on white-fruited variety
Leafroll on white-fruited variety

Statewide IPM Program, Agriculture and Natural Resources, University of California
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Agriculture and Natural Resources, University of California

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