I'm in North Carolina right on the I-95 corridor. I have some big, fairly vigorous tomato plants in my garden in which the tops are starting to yellow. The veins in the leaves remain green at first while the rest of the leaf turns yellow; then finally the whole leaf goes. So far only about the top third of the plant is infected. The two worst plants for this are some cherry tomatoes, but some of my slicing tomato vines are starting to exhibit the same signs.
It has been a little dry over the past weeks, but we've had some rain over the past few days and I've been watering, so water stress should not be a problem. There are no insect pests that I've noticed, although it's likely that there's an aphid or two in the mix somewhere. Over the course of the summer I've fertilized my 25x25-foot plot with ten pounds of commercial 10-10-10, watered in.
What do you suppose is causing the problem?
Maybe gardengirl can help out with your question in post 187.
Hey Red, Oberon!
At work so I’ll have to keep this short.
Are your plants in the ground? Any disease that tobacco can get, maters can get. Not a definite answer here, but it sounds like your maters have some kind of blight.
More later. :)
If you can’t find the answer here, you don’t have a problem, LOL! (Look at the pix of fungal and viral problems.)
My guess is blight, but it could also just be weather related because it has been one cool and dry summer in a lot of the USA.
Blight starts from the top of the plant and wilt starts from the bottom, usually.
http://www.avrdc.org/photos/tomato_diseases/index.html