comments:
NPKzone8a posted on r/tomatoes1w
I've got to tell you honestly that I'm not sure I am right, but I would probably just cut off the worst bits, the leaves that are deep yellow, brown, or crispy. When in doubt about which pieces to cut off, better to do too little than too much. For next year I would start spraying with a copper anti-fungal preparation such as this one link when the plants have been in the ground about a month, before you can see any signs of disease. It is a preventive, and that works much better than attempting a cure after the problems start. (Not everyone agrees with this strategy, but it's what works best for me.)