Verticillium wilt affects many herbaceous plants, including dahlia, gerbera, marigold, peony, snapdragon, and vinca. Leaves infected with Verticillium wilt and turn yellow, first at the margins and between veins; foliage then turns tan or brown and dies, progressing upwards from the base to the tip of the plant or branch. Browning of older leaves while younger leaves remain green is also characteristic. Woody plants are often affected first on one side of the plant or only in scattered portions of the canopy. Water-conducting tissue in branches and stems may darken in some hosts. Infection usually occurs during cool conditions but damage may not become apparent until warm weather when plants are more stressed.
Solutions
Sanitation and resistant plants are the primary strategies for managing Verticillium wilt. Plant only pathogen-free plants. Avoid planting susceptible cultivars. Plant in disease-free soil. Solarization can reduce Verticillium fungi in the upper few inches of soil. Keep plants vigorous by providing proper cultural care.
