I don't think it's a bug problem, bingo. I don't know of any insects which can cause wilting like that... I'd stop spraying, as it probably isn't doing anything but costing you money.

That branch-by-branch progression you're describing is extremely typical of a fungal or bacterial wilt. They persist in the soil for years, and in the case of the fungi, some varieties handle it better than others.

My biggest question is: do the leaves turn yellow, or just limp floppy green all of a sudden?

If it's yellow I'd say Fusarium wilt, a fungus -- it's what is named by the F in "VFFNT", which you find on some hybrid tomato labels. Sadly, hybrids with tolerances like the ones listed in VFFNT only last another week or two; it's important to a farmer trying to get out a crop, but not so useful to a home gardener. The only solution I know of is to stop growing any susceptible plant in that bed -- anything in the nightshade family, which has tomatoes, peppers, eggplant, and potatoes -- and grow them in containers with store-bought soil, raised off the ground. If you use the same tools all over the garden, it will spread.

If it's floppy green without a hint of yellow, cut off one of the affected stems and stick it in a glass of water. I can just about guarantee you'll find milky streams coming from the cut end within minutes. It's a sign of bacterial wilt, a nasty critter with no cure that's usually brought in with store-bought transplants. The only way around it is, again, to stop using the bed for anything bothered by it and switch to isolated containers with uncontaminated potting mix.

I find bacterial wilt a lot less likely, though, as it tends to nuke every tomato plant out there and shouldn't spare your grape tomatoes. My money's on Fusarium.

--Alison

Alison, thanks for getting back to me. The branches and leaves just go from a healthy green to a dead green. Totally limp. They don't get yellow. The plant will slowly die branch by branch.
I have in the past have gotten a wilt. Where they start at the bottom of the plant. Slowly getting yellow. And dying from the bottom up. If I catch it in time. I start a weekly spraying program. And it usually works.
I used to just plant one kind of tomato. "Jetstars". But here in the past 4 or 5 years. I plant several kinds. I always at least one or two kinds of tomato that has VFFNT on the tag. That does make a different. Usually if I do get a wilt. I still will have some tomato plants survive.
After we got some heavy rains along with my dusting and spraying. I haven't seen any more damage.
Dan

Vascular wilts can't be stopped by spraying... I wonder whether it was coincidence that it seemed to help, or whether what you had was really a leaf blight instead. I don't know.

I'm glad you aren't getting any more damage, but frankly, I'd lay off the dusting and spraying if it's just for these wilting symptoms. Nothing you spray can help the plant if the path from the roots to the stems is plugged up, as wilts do. If you have significant insect damage or leaf spots, then by all means keep up treatments for those.

Best of luck for the rest of the season.

--Alison

I thought 2 or 3 times in the last couple of years I had this problem figured out. I know that I haven't fall plowed in the last couple of years. I wonder if I should go back to it. Maybe I can buried some of the problems.
I move things around every year. I never plant the same thing twice in the same area.
Is there anything a person can do for wilts?
Dan