What I know about fusarium wilt I read just now on Wikipedia
It looks like cleaning out the plants and leaf litter from the location is helpful. Whether you would want to compost this or put it in the trash is a question someone else may answer.
There are anti-fungal activities and treatments you can do in the garden. In other plants, spraying regular store-strength hydrogen peroxide treats powdery mildew (a fungus) - perhaps using it regularly on your tomatoes in that area. And look for resistant varieties of tomato to plant in the future. Sprinkling corn gluten meal (also antifungal) over the area might help, and there are copper fungicides that serve as arrows in the organic quiver that you might research.
Be sure your soil is well-drained and don't over-water.
This is an educated guess only. These are things that I do in regard to early blight in my tomatoes (and early blight is one of the reasons why it's a good idea not to water your tomato foliage when you water the plants, if you can manage it.)