pith necrosis of tomato
Pith necrosis-this disease is not usually an important problem. Irregular necrotic lesions on the stem are characteristic. Stems may become dark and twisted. Pith necrosis is more often found in a greenhouse or high tunnel than in a field.
Figure 1. Initial symptoms of pith necrosis of tomato may appear to be minor necrosis on the stem. 
Figure 2. Dark pith necrosis lesion on tomato stem. 
Figure 3. Early symptoms of pith necrosis of tomato. 
Figure 4. A dark lesion of tomato pith necrosis extends along the stem and leaf petioles. 
Figure 5. Pith necrosis of tomato can sometimes cause internal stem discoloration as seen here. 
Figure 6. Dark necrosis on stem and chambered pith caused by tomato pith necrosis. 
Figure 7. Tomato pith necrosis. 
Figure 8. A portion of a tomato plant with symptoms of pith necrosis has begun to wilt due to stem lesions. 
Figure 9. Withered stem due to tomato pith necrosis.