See:
Greenhouse Plants, Ornamental - Impatiens Necrotic Spot
Symptoms Small, necrotic spots can develop on leaves, or leaves can be scorched. Plants generally look ratty and die back. Both tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV) can infect verbena.
Reference Warnock, D.F., and Loughner, R. 2002. Verbena cultivars differentially attract adult western flower thrips. In XXVI International Horticultural Congress: Sustainability of Horticultural Systems in the 21st Century 638, pp. 89-94.