The dude at Merrifield's Plant Clinic used the two dreaded words: "late blight." I've got 2 other tomato plants, both also grown from seed from a freecycler, that are looking pretty ill. I can't find stem lesions on them or the tell-tale white "mold" on their leaves, but it could just be that it's in the early stages. He ruled out Fusarium wilt and early blight and some other fungal diseases. It was basically late blight by elimination. Not exactly a death sentence per se, but I'm not going to wait around to see what happens.
So, my Green Zebra and Cherokee Chocolate tomatoes along with the Mystery Freecycle Heirloom tomato are going directly into trash bags & my gardening gloves are going into the washing machine and any shovels used are getting sanitized. Perhaps this is overkill, but whatever. The Sungold & Wonder Light tomatoes are looking fine (and, tonight I harvested my first Wonder Light!). I'm also a bit concerned about my Cherokee Purple.
But, I don't feel as sad about this as I had expected. We've probably gotten at least 6 pints out of our Sungold tomatoes so far & they are still producing like crazy. This year hasn't be a total loss (especially b/c the Sungold are some of the most delicious tomatoes I've ever tasted!).
Plus, when life gives you late blight, make fried green tomatoes!
(The plants had several full sized but unripe tomatoes on them)