The browning of stem tissues is generally visible up the stem for 18 to 24 inches. Southern stem blight is also a common disease which shows up later in the season, particularly following several days of wet and hot weather. This disease is easy to identify. Infected plants wilt and die very quickly. Look for the key symptom, which consists of white web-like fungus growth near the soil line.
Bacterial wilt is a common tomato plant killer in the southern part of the state.
This disease is more difficult to identify, but a close check for a few give-away symptoms will help identify this disease. Bacterial wilt affected plants often look perfectly healthy in the morning but by mid-afternoon, look as though they have had hot water poured on them. Root-knot nematodes sometimes cause death of susceptible tomato varieties, but more often, these nematodes are associated with stunted growth. Several other problems which may cause death of tomato plants are not related to fungus or bacterial diseases. Over fertilization leads to burning of roots, irreversible plant wilting, and frequent plant death.