Looks like late blight to me, and makes me very nervous to hear that you've got it down in zone 10 already. Since the plants will die anyway, pull them and burn them or seal them in an airtight trash bag and dispose of them right away, to try and prevent spreading the disease. The spores are airborne and can travel downwind to infect other tomatoes and solanaceous plants. Sorry about your tomatoes!

With respect, I hope you don't follow Catman's advice right away. It looks like septoria to me and I just had the exact same disaster you are experiencing because of the cool, moist weather we've been having on the CA coast. Here's what I did and my tomatoes went from looking like yours to being almost healthy, with lots of fruit:

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1) Pick or cut off EVERY single infected leaf where it meets the stem;
2) Stop watering for a few days;
3) Dilute household bleach to 10% of its original concentration and put the mix in a clean spray bottle;
4) Spray remaining leaves, avoiding the flowers if you can;
5) Mulch the tomato bed to try and keep the septoria down in the soil, not up on your plants' leaves;
6) Water after a few days, being careful to not spalsh ANY soil up on the tomatoes;
7) Follow Catman's advice when the plants are finished producing.

If any plant looks done, then toss it (following sterile procedure). If they all look done or my way is too much work, then Catman's suggestion is best.

Yeah jean I agree the leaves don't look as much like LB but the stems look a lot like LB. My plants died within days late last summer after they finally got the blight (which I probably carried home with me from the infected community garden). So far no LB symptoms yet this year and I hope it stays that way.

"It looks like septoria to me..."

To my knowledge septoria is a leaf-only disease also refered to as "septoria leaf spot." The dark lesions on those stems look exactly like late blight and based on the extent of the damage - catman's advice is also my own.

It's possible the plant has both septoria and late blight, but it almost certainly has late blight.

You should not burn infected leaves, that will spread the spores. Double bag them in black or dark green garbage bags, then lay them out on a concrete walk or pavement when they won't be disturbed for several days and let them solarize. Late blight can only survive in living plant tissue, so solarizing the infected plants should take care of it.

Betsy

Thanks everyone. I'm going to try the bleach solution and see what happens. If they're dead in a week, I'll solarize and dispose.

Thanks!

I just wanted to bump this to check on any updates.

ncalsurfer QUOTE:
"Thanks everyone. I'm going to try the bleach solution and see what happens. If they're dead in a week, I'll solarize and dispose."

That couldn't have been easy to to write my hopes are that the bleach works if not my sympathies for what we all dread happening in our own gardens.

I know 6 years later and I'm buzzing in. Well, this just happened to my tomatoes and I'm no gardening pro! But, I saw some tiny poop that had me wondering who it belonged too. I thought maybe my tomatoes were getting too much sun and thats why its was turning colors but I did some googling. I found out, I had a Catapillar living and eating my plant! I sat down and stared at my tomato plant wondering if I would find this mystery Catapillar and then all the sudden right in front of my face there he was, about the size of my finger, but blended in so perfectly to look like a leaf. I stared at my tomato plant wondering if I would find this mystery Catapillar and then all the sudden right in front of my face there he was about the size of my finger but blended in so perfectly to look like a leaf. After posting this discovery on fb. all my gardening pros warned me that he would kill my plant totally and move on to the others. As well as lay larve. Yuck! Well, upon looking at your photos I think I found his cousin hanging out in your photo!! The close up was the one in my garden. So you can see it better. It's a tomato horn... Yours may be in a different family. But it's a catipiller!

Anto, just so you know... the hornworm itself doesn't 'lay larvae'. It is the caterpillar stage of a moth. and yes, they can be extremely destructive. The moth lays eggs which hatch the caterpillars. If unchecked, the hornworm would continue to eat and grow. It would then spin a cocoon and pupate into an adult moth, the cycle to begin again.

This same disease is happening to my tomato plants. But I highly doubt that it is a caterpillar.

So on some brown areas i tried to scrach them off just to see what happens and after a little scratching the brown surface it became green then i left it for about a week and the same area has become brown again.

So I have scratched it off again and now have placed a tape on it. See what happens now.

Bleach solution spray is the most effective when the disease has advances. Chlorine kills the fungi at contact. I have a similar mild case ( some browning stems ..) I have bee spraying with 7% Clorox and things are under control.

When you do that you will see some affected leave die the next day or two. Dont worry about it .

Also I think LIQUI COP is effective. Use it at the highest recommended doze.

Sey

PS: HAHAHA. I just realized that this is a vantage thread. My post is too little too late.

Yeah, zombie thread.

I note that the original was from 2010. Wasn't that the year of the terrible late blight that destroyed tomatoes and potatoes all over the country? I suspect the OPs tomatoes did not survive long after that post, sadly, and that the advice to treat it like septoria (which it quite obviously is not) was very bad advice, both for the OP and anyone around him/her growing tomatoes or potatoes.