See:
Greenhouse Plants, Ornamental - Impatiens Necrotic Spot
Symptoms Young plants' symptoms may look similar to infected Gloxinia's, but older plants have ringspots and line patterns on leaves. Leaves may show small round yellow spots or larger chlorotic patches with diffuse borders. Dark purple to brown sunken lesions appear on petioles, often at the leaf junction. The petiole may be girdled, or lesions may move into the stem. Can look like chemical spray damage. Flowers may bloom fairly normally even though the foliage is devastated.
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.