Symptoms
- Yellowing and browning of lower leaves, often in a V-shape from the leaf margin inward
- Wilting during the heat of the day with partial recovery in the evening
- Browning of vascular tissue visible when stem is cut — usually more brown than Fusarium (which tends salmon)
- One side of the plant often shows symptoms before the other
- Disease progresses slowly compared to Fusarium — plants may survive much of the season with reduced yield
Life cycle
Verticillium dahliae produces microsclerotia that can persist in soil for more than ten years. It has a wide host range including strawberries, potatoes, and many ornamentals. Infection occurs through roots, and the fungus colonizes the vascular system. Cool soil temperatures (65-75°F) favor infection — unlike Fusarium, which prefers hot soil. The disease tends to be less aggressive in warm climates.
Management
- 01Plant resistant varieties — look for 'V' in disease-resistance codes
- 02There is no effective soil treatment for home gardens — prevention through variety selection and rotation is key
- 03Maintain healthy soil organic matter; well-amended soils may suppress the pathogen somewhat
- 04Avoid planting susceptible crops (tomato, eggplant, strawberry, pepper) in the same bed for three or more years
- 05Soil solarization in summer may reduce inoculum in the top layers of soil
- 06Remove and dispose of infected plants and debris — do not compost
Resistant varieties to try
If this keeps happening in your garden, the single most effective change is often the seed packet. These varieties carry documented resistance.
When to call extension
Verticillium and Fusarium wilt can look nearly identical. If you're losing plants in a bed where you've been rotating crops and planting resistant varieties, an extension plant pathologist can run a lab test to confirm which pathogen is present — this matters for management decisions.
Sources
- Verticillium Wilt— University of Minnesota Extension
- Verticillium Wilt of Vegetables— Ohio State University Extension