The disease causes old leaves to turn yellow with a characteristic V-shape that narrows from the margin. Symptoms are similar to those of Fusarium wilt and are only noticed during fruit set. Older leaves turn yellow then brown. They wither and may drop early. The disease rarely kills the tomato plants but it reduces vigour and in the long run reduces yield. The loss of foliage exposes the fruits, increasing the risk of sun damage to the fruit.
The disease is spread in soil and remains in the soil for a long time. It is caused by a fungus which enters the plant through the roots. Root knot nematodes make the infection more likely. The disease has a wide range of host plants including weeds. Disease survives best on alkaline soils.
- Use of resistant cultivars helps to control the disease.
- Avoid planting in fields with a history of disease attack.
- Remove and burn the diseased plants.
- Avoid alkaline soils which are good for the disease spread.
No known chemical is effective in the control of the disease.