The symptoms of mosaic vary considerably, depending upon the cultivar grown, which virus or viruses of the complex are involved, and time of year. Symptoms are most evident on new canes during cooler weather of spring and fall. Symptoms may disappear in the summer when temperatures are high. This is an important point to remember when considering control of virus diseases. Even though symptoms may disappear temporarily, plants remain infected for life.
Infected canes are usually short and less vigorous than healthy canes.
Leaves are mottled with yellowish or light green spots on a darker green background. Leaves that develop in hot weather may be symptomless or show only faint mosaic pattern with yellow flecks in the normal green color. Leaves formed in late summer show a fine, yellowish, speckled mottling. Mosaic-infected plants are often progressively more stunted each year. On black and purple raspberries, the tops of newly-infected canes often curl downward, turn black, and die.