So sorry for your tomatoes as there is no fungicide that is effective on fusarium wilt. This disease spreads upwards by turning the stems then leaves yellow. The leaves will wilt before they die but some tomatoes may ripen before this happens. Remove and destroy infected plants. Good sanitary practices and planting resistant tomato varieties are the best way to prevent this. A few tomatoes resistant to fusarium wilt are Better Boy, Better Girl, Homestead, Marion, Burpees Big Girl and Supersonic. Don't give up you'll have a fresh start next year. Keep growing, Marianne Binetti