Fusarium wilt and Fusarium crown rot symptoms begin as yellowing of older leaves. With Fusarium crown rot, the leaves often turn brown or black and eventually wilt. With Fusarium wilt, the yellow leaves turn downward and droop.Fusarium oxysporum, the cause of both diseases, is a common tomato fungus that lives in the plant's vascular system, which carries water from the roots to the leaves. To see if either of these diseases is present:
- Check watering practices. Both over- and underwatering can mimic disease symptoms.
- Check the roots. Discolored roots indicate root rot.
- Cut the lower or main stem and look inside at the vascular tissue. Fusarium wilt causes a dark brown discoloration within the vascular tissue. Fusarium crown rot causes a rot or canker at the base of the stem and possibly a root rot. (We found when we cut open the stems of infected plants the entire diameter was brown.)
Most tomato seeds or transplants are labeled with a code such as "VFN," "VFNA," "VFNT," etc. This indicates that the plants are resistant to Verticillium wilt (V), Fusarium wilt (F), southern root-knot nematode (N), early blight (A), or tobacco (tomato) mosaic virus (T). Do not plant tomatoes, potatoes or eggplant in the affected area for two or three years.
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