What's the best variety in terms of being fungus/blight resistant? This is my biggest problem with growing tomatoes. The blight seems to be everywhere in the soil on my garden spot, which has been in steady use for around a century. Moving the tomatoes to a different spot doesn't seem to have any effect. Fungus was also attacking my okra to the point that I had to start a new plot for okra that's around a 100 yards away. That worked well for the first couple years, but last year the fungus started hitting my okra again. I've been spraying with copper fungicide, but it seems I'm always too late with the spraying. I understand that once you see the leaves turn brown and die off, spraying won't do much good anymore.
Is this Early blight (Alternaria solani)? Or Septoria leaf spot (Septoria lycopersici)? Septoria is relatively easy to control, Blight not so much.
There are blight-resistant tomatoes, of which Legend (developed by Oregon State for the purpose) is the most widely available. Mind that no plant is 100% immune however.
Best treatment for blight is a two pronged attack.
First, use plastic mulch sheets. Alternaria spores winter in the ground, but do not attack roots, only leaves and stalks. Insulating the plants from the soil can help a lot.
Second is to treat with copper fungicides on a schedule. I cannot stress the importance of scheduled treatments enough. I usually treat my tomato plants just before transplanting them, then every two weeks. If the weather's rainy, make that every week.
Once plants are at least 3ft high, it may also be a good idea to eliminate the lowest leaves to reduce the chances of contagion even further.