Wilt Diseases of Tomato Plant Pathology Wilt Diseases of Tomato The fungi Verticillium and Fusarium can cause infectious wilt diseases of tomato. A number of plant samples have tested positive for wilt diseases this year. These soilborne fungi enter the root system of the plant and eventually plug the plant's vascular tissue. This leads to yellowing and wilting of plants leaves, usually working from the bottom of the plant upward.
Infected plants die early, often producing little or no fruit.
In addition to the wilt symptoms, infected plants show a brownish-red discoloration of the vascular tissue in the lower stem. This can be visualized by cutting through the lower stem and crown tissue with a knife. The discoloration may extend up the stem some distance. Tomato plants are available that are resistant to Fusarium and Verticillium wilt. Resistance does not mean the plants cannot be infected.