What sort of herbicide (weed killer) has been used in the neighborhood, including weed-and-feed?

I have used Round Up in the yard. Also I used Scotts fertilizer with crabgrass preventer in the early spring on the lawn.

Is the lawn anywhere near the tomato plants? I'm guessing not, as it doesn't look like herbicide damage is the prime suspect. Do the new leaves, the youngest ones, look normal, or are they as bad or worse than the ones in the picture?

If the new leaves look fine, and continue to look fine, then just leave the plant alone and let it grow out. I'm pretty sure they won't be, though... that looks like a viral symptom to me, and viruses rarely get better.

I'll be honest with you: early in the season, my only currant tomato had leaves somewhat like this after I planted it out. I knew I'd probably have to pull it, but I took a chance on it and decided to wait and see, because I really wanted currant tomatoes this year. It kept growing, while virus-infected plants tend to slow down or stop; newer leaves looked better and better, until it was growing very quickly and all the foliage was normal. It's set fruit now. Odds are it was just some environmental conditions early in the season, but it really looked viral to me.

So you can take a chance and wait a week or two to see whether it improves, as it may if it's environmental or herbicide-related... the risk is that if it is a virus, there is some chance of it spreading to your other plants if you leave it in the garden. You'll have to decide how important that plant is when compared to your other tomato plants, take a hard look at its growth rate and how normal the new leaves look, and choose whether to pull it or leave it. It's a tough choice.

Let us know if you have any other questions.

--Alison