An early symptom of fusarium crown is the 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 water conducting vessels. when tomato crop are produced intensively under glass. The disease attacks field crops in fumigated soil.
