Wondering if this is fusarium or verticillium wilt? It started a few days ago and is progressively killing the plants. I don't remember the variety name. We have had tomatoes in the same area for a few years. We are going to destroy the infected plants and will move them to a new location next year. There is also a black walnut tree on the other side of the garage from this garden bed, but it's been there fore years-long before the beds were put in about 4 years ago. The bed is 15 ft long, the neighboring tomatoes down the row (I planted several different varieties) look healthy. Is there any thing I can do to prevent the spread to the healthy looking plants? Thanks!
Mulch under your plants and use a soaker hose to water them or hand water at base of the plant. Don't water from overhead for a start. Next year plant resistant varieties choose tomatoes with N,V,F resistance and do not plant where tomatoes have been planted in the last 3 years.
You can nurse the plants along by giving them enough water and still get some good fruit depending on the disease agent. Tomato plants can loose almost all their leaves and still produce fruit. It looks like they may have early blight and septoria. The very hot, wet weather is causing a lot of wilts and blights this year.