[Subversive_plot]

I have a plant of Purple Ukraine that was picture perfect yesterday, with many fruit set.  Today, the top half is severely wilted.  Many of the lower leaves look ok, but some are also wilted.  None of the leaves have spots, yellowing, etc., as of yesterday, all green.

Some factors to consider.
1.  We had a tremendous amount of rain over the past week, through early morning yesterday.  About 6 inches of rain for the week.
2.  It suddenly got a lot hotter yesterday reaching 32^oC, after being 27^oC or lower most of the last week, with all that rain.  Hot again today.
3.  I looked for, but did not see, evidence of insect damage or mechanical damage to the stems or anything else.  I am not ruling out stalk borer, but don't see signs of that.
4.  ATM, I am not seeing other symptoms that would suggest V or F wilt.

Any ideas what may be happening?

[Subversive_plot]

Unfortunately it looks like the problem is in more than one plant.  Symptoms I see now suggest Fusarium wilt, though I haven't "autopsied" a plant yet to confirm.

[mumofstig]

Bad luck  Hope it doesn't spread to your other plants 

[Subversive_plot]

Autopsy confirms the damage is Fusarium, with characteristic browning of vascular tissue in the stem.  Not all tomato beds are affected (touch wood).  Pulling affected plants out tomorrow morning.

While I was having a tomato disease pity-party of one, I came across a couple of very useful information pages on disease-resistant tomato varieties:

https://www.vegetables.cornell.edu/pest-management/disease-factsheets/disease-resistant-vegetable-varieties/disease-resistant-tomato-varieties/

https://www.gardeningchannel.com/top-disease-resistant-tomato-varieties/

[Subversive_plot]

Problem managed.  I pulled out 2 plants, and will see if it stops there.

I will be closely watching the remainders in that raised bed.

Photo attached, showing the brown vascular tissue in a stem that is split open.

[mumofstig]

That's weird, I've never seen anything like it before - I've just been lucky, obviously