If it didn't happen over-night, then it could have been lots of things. A lot more information is needed to find any cause or causes. One thing I can offer is that as those leaves do die (and some lower leaf die-back is common,) remove them. If I don't see any symptoms of serious disease, I remove the leaves after the green is gone and the petiole has turned yellow. Some people remove them before that stage, but I like the plants to reuse those nutrients. The easiest way to know is to lift the leaf, then 'snap' is back down. If the plant is 'done' with the leaf it will come off clean. As you've learned that 'point' then you can use scissors or pruners on the stubborn ones.

The reason for removing those dead leaves is mainly to allow airflow, and to remove any dead matter where disease and fungi can set in and flourish.

Agree. With any of the common tomato problems (except Late Blight) it is a relatively slow progression that when caught early can often be cured or at least slowed down. Sometimes all it takes is removing the affected foliage as it develops so that it doesn't keep spreading. Dead and dying foliage left on any plant serves no useful purpose and often only contributes to the spread and rate of contamination. But by this stage of progression, when there has been no intervention, it is impossible to know what caused it much less how to cure it or prevent it from happening again.

I note the plants are not mulched which I'd think would be mandatory in her climate. So it could be something as simple as far too little water or inconsistent watering to one of the common diseases. The pics actually look like a set of plants that has had little to no water provided and if I saw them in person that would be the first thing I would ask - water?

The support structure could also use some work so there would be fewer broken branches. Perhaps even some better spacing if the air flow and circulation is inhibited by the fencing. But I doubt those are the causes of such total destruction.

The squash plant in the corner of the one pic looks like it may have powdery mildew so that is one possibility with the tomato plants as well. But one really needs to see and ID the symptoms as they develop, not when it already done killing. Best that can be said is that it doesn't appear to have affected the fruit so she lucked out there.

But this is all just speculation at this point.

Dave

So, if I don't keep on top of my tomatoes here in southern California, those pictures are identical to what happens every year pretty much without fail. I'm not even quite sure what is doing it, but I do also normally have early blight every year (regardless of mulching, rotating, etc), so maybe that is advanced early blight, if you just let it go and don't treat? I've not had it happen to plants that didn't already have signs of early blight, if the experts can do anything with that information.

Anyway, I just have to get out there daily and remove the stuff that needs it (which includes heavily affected plants like your pictures if she has any healthy plants left to protect), spray fungicide as necessary and try to keep ahead of it...some years it works better than others. This year has been awful (blight, mildew and mold, oh my! lol) and so has our weather, not sure how northern Cal compares and whether that is a factor.

Just one of those things where I think she needs to be dealing with problems as they arise, before they get to this point. Any fruit she gets should be fine, I've never had fruit problems until the disease just got the plant to the point it didn't produce anymore. Normally the fruit just gets smaller and smaller as the plant slowly dries up and dies, or the flowers start turning brown like the rest of the plant and don't get pollinated.

Agree with Digdirt on the squash, also noticed it and was going to say something. That's another of my forever-battling-it garden issues. Don't know if she noticed it, and can't tell from the picture if it's one of those silver-veined squash, but if it is powdery mildew, that will spread like wildfire as well if it's not gotten under control early. I can verify that the dried brown leaves on the tomatoes in my garden are not powdery mildew related, though. Two different issues, I think.

jensubzero1, did your friend fungicide ?

I also agree that mulching was - is always - necessary.

Thank you so much everyone, I wish I could've asked for help sooner for her. This is a lot of good advice for the future. She had well water set up to water the plants and when she noticed the leaves dying, she supplemental watered with the hose. Not sure if she's able to see how much well water the plants got. I don't think she used fungicide. I believe when she saw it dying, she just supplemental watered and other than that, was completely mystified what had happened. I do know she didn't see any droppings from critters.

I'll let her know about the powdery mildew on the squash too.

thank you fellow tomato-gardeners!
Jennifer

Looks like Late Blight , to me !!

Kills the plant and fruits are not affected. JMO

Sey

At least on mine (which look exactly like the OP pictures when I have a bad year), there aren't the lesions/black spots on the stems or leaves, and I've always understood that late blight will leave rotten areas on fruit and kill fairly quickly? Mine progresses fairly slowly if treated, and the fruit is completely normal and tasty other than getting smaller and finally just not growing as it progresses. I've also had plants that were affected but not as badly as the pictures, which have bounced back once the cool autumn weather hits...which I understand is not the way that late blight works unless I'm completely confused. I've never actually dealt with late blight so my information is all off the google ;)

*edit* forgot to knock on wood. phew, close call...

So, my pictures aren't nearly as good as the OP but here's a couple that have been dealing with what appears to be the same issue.

This one's a Brandywine that I started late and decided to leave in to see if it bounced back, since I haven't yet had any fruit on it. Sorry for the horrible picture, but you can see the dead brown leaves (although I've picked off most) on the back left side of the new growth. The new growth has just recently started, so this one might be an example of bouncing back, waiting to see.

This one is a San Diego, which has been a trooper as far as being very slow to succumb to whatever it is. You can see I need to get in there and pull the dead leaves out, but it's a good picture to show that the fruit is unaffected and still producing, though a little smallish.

Anyway, if I'd not been pulling dead leaves, spraying and cleaning up as much as possible, they'd look exactly like the OP's. I don't have a clue what it is either, just that it happens to one degree or another every year in my garden, is usually somewhat controllable, the fruit seems unaffected until the plant is just too weak to produce anymore, and that I've had plants bounce back completely and produce throughout the winter. Dunno?

I doubt it was lack of crop rotation tho I don't know the garden end of season cleanup or sanitation routine.

fwiw - I have been growing tomatoes in the same bed for more than 10yrs. I never remove plant roots and certainly I could clean a lot better myself.

I guess a root disease or problem could be a problem here tho. Ask her to try pulling a few up to see.

jensubzero1 - lack of water is a real possibility - do you know if plants were watered via a sprinkler or similar method? Did they begin with powdery mildew by any chance?

Humsi it is normal for the lower leaves on tomato plants to die off. They often catch disease from the bottom up also.

Late Blight rots fruits and stems, very rapidly. It doesn't look like LB to me. JMO. Also I don't think there was LB in Cali in July.

Could maybe be Fusarium... were they transplants purchased?

gumby, you are in zone 5 and OP is in zone 9.... it is apples and oranges.

Yeah, I know, but what the original pictures are showing is the late stage of what my two photos are showing. It skips around, also, where you can have brown die-off at the growing
tips while skipping the rest of the plant in the beginning. I've pulled 3 plants already this year that, had I not picked off the leaves trying to save them, would have looked exactly like the OP's plants, and now I'm wishing I had pictures. Might not seem like a big deal given the time of year, but in my micro-climate tomatoes can grow and produce until early winter or even into early spring. I also have completely unaffected plants in different areas of the garden that were from the same seed batch and planted at the same time as the ones I've pulled (ironically the ones that are fine are in an old tomato bed and the diseased ones were in a new-to-tomatoes bed). It's not just normal aging leaf die off, it's something else.

<it is apples and oranges.>

"it " refers to what?

crop rotations / overwintering diseases.

Oh certainly, esp disease overwintering.

Did I forget to mention I don't know the garden end of season cleanup or sanitation routine?

Unless and until the root cause is determined I don't see how anyone could conclude crop rotation was the cause or a factor even.

I don't know what my friend's end of season cleanup is either. I'm going to ask. I'm just so sad to see this happen to their "babies". So much hope and expectation for the growing season, it's unfortunate.

As for the watering routine, I believe she has an irrigation system setup to run with well water. She also thought it was possibly the watering, so she started to water more with her hose by hand, but it didn't seem to make any difference.

The plants were all started from seed she saved from last year.

Late blight doesn't seem to fit as the fruit is all fine. A quick google showed that the fruit would've been mottled brown.

The problem does seem the same as Humsi's first picture. Those leaves that are brown are way up from the soil level, at that point, the leaves shouldn't be affected by soil illnesses or whatever critters crawl around on the soil.

Thanks Peter, it does seem to resemble Fusarium. Just found this page and that photo sure looks similar: http://www.growgardentomatoes.com/crown-rot.html

Jennifer

I did some research last night and I'm starting to think it might be spider mites or russet mites. I guess posting all of the things I've noticed happening and when it happens, when it gets better, etc triggered a thought that it might be insects instead of disease. I went out and checked and there are some spider webs, which I'd noticed before but we have a ton of normal spiders and I'd never really thought it wasn't just...spiders. Something for her to possibly look into. I'm definitely going to start a neem oil treatment next year to see if I get better results. Thanks for posting those pictures, you finally got me thinking!

http://pixcooler.com/mites+tomato+plants?image=195485732

Interesting, never heard of russet mites. Thanks Humsi for another possible problem. I'm learning so much!

My leaves turned overnight. I since found many answers, but I have a Tomato Factory, so 3 Plants was doing fine. Fl so storm we cover with Plastic, worked fine, but last storm, they sprayed the grass with weed Killer & the plants are next to the grass not on it, so rain that night, covered plant, in am looked like this photo. The Stems are a lot Green brownish at stem tomato's still growing. So what was it? Heat damage from Plastic left on 2 hours too long in am. no real air circulation? Or was it Weed Killer? or could I have over Fertilized it a week earlier? Plz help??