Symptoms Verticillium wilt symptoms usually do not become conspicuous until the third production year. Affected plants are scattered throughout a field, but occasionally occur in large patches. In the early stages of the disease, leaflets wilt during periods of slight water deficit, but may recover at night or after a light rainfall. A yellow, V-shaped discoloration at the tip of a leaflet is an early indication of Verticillium infection. These abnormally small, twisted leaflets occurring near the top of the stem are the most characteristic symptoms of the disease.
Stands become thin as infected plants die.
Symptoms of Verticillium wilt in alfalfa. Upper leaflets are small, yellow to pink, and frequently curled or twisted. This is especially true if stands are to be maintained longer than 3 years. On farms where the disease has been identified, it is absolutely essential to use a Verticillium-resistant variety. Most seed companies now have one or more varieties with Verticillium wilt resistance.