We've been successfully growing Early Girl tomatoes at high elevation in northern AZ for several years until this year. We buy starts at a local nursery, use drippers and this year applied a wood mulch around the base of the plants. This summer the plants were doing great when in early July 1 of 6 plants started getting yellow leaves and wilting. It proceeded to lose a lot of foliage and became unproductive but didn't completely die. A kelp fertilizer did not help. The other 5 plants also had yellow leaves, primarily at the base, but otherwise appeared healthy. After our summer rains began in late July, 2 more plants started getting more yellow leaves and soon dead leaves. We pulled the 3 sick plants out to reduce spread to the other still relatively healthy plants. After reading about tomato diseases it seems it should not be verticillium or fusarium wilt (in theory Early Girls are resistant?) but instead a foliar disease but I am not certain of this. Any help with ID of this disease would be greatly appreciated (see sick leaves photo).

Image link: