Thinning of the stem at the top of the plant when it is l-2 m high. When the first trusses of fruit are ripe, or nearly so, the plants begin to wilt, particularly in hot weather and in full sunshine. The wilt progresses from top to bottom, and, when the plant is almost dead, the leaves may turn golden brown from the margins.
The disease is usually characterized by a remission of wilt symptoms on cooler and overcast days and after picking. The cause of wilt becomes clear when the base of the stem is examined at or just below soil level. A chocolate brown lesion extends through the external cortical tissues, girdling the stem in severe cases. When the stem is split open , the discoloration can be seen extending along the waterconducting vessels. In contrast to fusarium wilt, this discoloration rarely extends more than 20-25 cm up the stem. The fungus gains entry where adventitious roots break through the outer cortical tissues of the stem. Fusarium rot also affects the roots. The rot at the base of the stem extends into the primary root and often destroys it completely The survival of the plant then depends on adventitious roots that are formed in the stem above the lesion. As in the stem, the fungus attacks the roots where the secondary roots break through the cortical tissue.
