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.
