Cause Primula mosaic virus and Primula mottle virus have been found in a few primrose species. Both are potyviruses and can be spread by aphids or by mechanical inoculation. Several mottle viruses also have been described on primrose, but their occurrence in the Pacific Northwest is unknown.
Symptoms Plants are yellowed, stunted, wrinkled (rugose) with cupped leaves. Flowers are streaked with white. Leaves are distorted and coarsely mottled with yellow-green areas. Some references state that yellowish or whitish mottling can be due to overmaturity or excessive fertility.
Cultural control Remove and destroy infected plants.
Reference Brunt, A.A., Crabtree, K., Dallwitz, M., Gibbs, A., and Watson, L. 1996. Viruses of Plants. Descriptions and Lists from the VIDE Database. Wallingford, UK: CAB International.