Here is something you might find interesting... My garden had plenty of early and late blight and septoria leaf spot. The following year I installed a hoop house over half of it and planted tomato plants inside and out (8 in/10 out). I sprayed/coated the outside plants several times (during wet periods) with a well known product used to control these diseases. The inside plants were treated only once (lower leaves only). Soil was the same inside and out (top quality and ammended-well with organic compost). The plants in the hoop made it all the way to freeze disease free! No blight at all inside. The outside plants, well, they were pretty much toast about 45 days earlier. The hoop house makes it sooooo much easier to garden. Never had to worry about pruning wet foliage (as it was often wet outside from the morning dew and rainstorms). The hoop house was not sealed off. It was about 50% open (no side or end walls). The plastic on top kept the direct rain off but there was some splashing along the sides. (I use leaf mulch to keep the soil from splashing up the stems). I can go on-an-on about the benefits of the hoop house but perhaps best is the reduction in plant disease. (but gardening during thunderstorms is pretty cool too!) My overall production was up more than 50%. And I suspect that with the dry and sunny conditions inside the hoop structure this winter (off-season), the bacteria and molds won't stand a chance (but I will still rotate anyway). One note, I trained my tomato plants to a rope attached to the top of the hoops. It grew vine-like plants vs. bushy plants you get on cages. It keeps the foliage drier and blight at bay. I am now less concerned about growing heirloom varieties. I hope I didn't get off topic.

Something is chewing on them. Perhaps slugs or snails. Go out at night & look.

Thanks, here is the answer from my local extension. I guess it is all over our area after 2 weeks of rain: Your tomatoes (and most tomatoes on farms) have septoria leaf spot, a fungal disease that is a little more aggressive than early blight. Most fungal and bacterial diseases start on the lower leaves and work their way up the plant. If you have the option to pull a few plants with this disease and plant some from a local greenhouse, that may protect the rest of the planting. If the spots are on too many plants to pull them all, then you can at least slow it down by removing lower leaves. Without a commercial fungicide, it may still spread.

Need pictures. If you posted them here earlier, please provide the link.