Sore shin, Rhizoctonia solani. This disease is a form of transplant rot occurring on older plants. Stalks develop a cankered area near the soil line or may be completely girdled just below the soil by a blackish collar. Mechanical injuries to the stalk help start the disease. Avoid damage to stems or roots during transplanting.
Older leaves develop both white and brown dead areas that resemble rust.
The newest growth on the plant usually shows the most severe symptoms of distortion and stunting. The virus is extremely persistent and can be carried in chewing and smoking tobacco, on hands, implements, and clothing, and in the soil on plant debris. The disease spreads readily from infected plants to healthy ones when handled during cultural operations. Control measures are based on sanitation to avoid successive handling of infected material and healthy plants. Avoidance of smoking or chewing tobacco when handling plants has proven helpful in reducing infection.