Peach rosette mosaic decline
Peach rosette mosaic
This disease occurs only in Concord and Catawba grapes in Michigan. Symptoms appear 3 to 4 years after infection. The plant canopy is umbrellalike with shortened and crooked internodes. Leaves are misshapen with a flattened base. Clusters are scraggly and may shell berries. Infected vines lack vigor, are prone to winter injury and may die after several years. The virus is spread by nematodes, infected planting stock and grape pomace. The virus also infects peaches and perennial weeds such as dandelion, horse nettle and curly dock. Boron deficiency and fanleaf degeneration may mimic this disease.