Symptoms and Signs
The first symptom of Fusarium wilt is wilting shoots. Bleaching of the leaf and stem color follows, and finally there may be a reddish tint to the foliage. In roots, dark reddish-brown streaks occur in the stele (the center part of the root that contains the vascular tissue). In advance stages, the entire stele may be discolored. The dark discoloration caused by Fusarium wilt is in contrast to the yellow-brown discoloration of bacterial wilt.
Comments on the Disease
Fusarium wilt is favored by high soil temperatures. Fusarium wilt was a significant disease in California, but resistant cultivars have now made this disease an infrequent occurrence. For more information on resistant cultivars, see the National Alfalfa & Forage Alliance website.