Unlike F. oxysporum f. sp. lycopersici , Fusarium oxysporum f. sp. radicis-lycopersici or FORL ( Fusarium crown and root rot ) is subservient to the root system of the tomato, on which it causes the browning of many roots which eventually rot (Figure 1). Usually, the xylem sections in the taproot and in some large roots also turn brown as well as, subsequently, the stem vessels (Figure 1). Thus, a brown streak, a few millimeters wide, can extend into it for several centimeters (figure 2). Subsequently, browning affects a larger portion of the vessels and can be observed up to more than 30 cm above the soil or substrate).
 

These various alterations cause wilting of leaflets and leaves rather located at the apex and / or yellowing of the leaves at the base of the plants. These leaf symptoms often occur as harvest approaches, on hot days, and when the plants are starting to be loaded with fruit.
 

Other symptoms are present on diseased plants, in particular crown cankers. For more details on this disease, we advise you to consult its sheet on Roots and Collar.
 
For additional information on this fungus, you can consult the sheet F. oxysporum f. sp. radicis-lycopersici .