See:
Greenhouse Plants, Ornamental - Impatiens Necrotic Spot
Symptoms Ring patterns may occur on the leaves of some chrysanthemum cultivars. Leaf distortion and necrosis also can occur. Necrotic streaks may be on the stems. Flowers also may be distorted with some necrosis. Symptoms often are on only one side of the plant. Plants produce fewer flowers, fewer petals, and lower flower weight.
Reference Daughtrey, M. L., Jones, R. K., Moyer, J. W., Daub, M. E., and Baker, J. R., 1997. Tospoviruses strike the greenhouse industry: INSV has become a major pathogen on flower crops. Plant Disease 81:1220-1230.