This has been asked a couple times recently:

https://www.houzz.com/discussions/do-my-tomatoes-have-blight-dsvw-vd~5393514

https://www.houzz.com/discussions/is-this-blight-dsvw-vd~5394106

Recommendations are to remove affected foliage, use a fungicide, and try not to grow in that same area again for several years. There may be other things you can do, "drowing" your beds with fungicide for example, and I will leave others to comment on if that would even be effective.

Do you mulch? Do you trim off the lower leaves on your tomatoes to avoid splash back? Do you get the leaves wet when you water or do you keep them as dry as you can?

I live in an area where Septoria blows in on the wind. Even when I keep my tomatoes in containers and drag them under an awning every time it rains, I still get Septoria. I think it falls in the dew.

I don't use sprays of any kind and usually I get enough tomatoes until frost. My plants look rather unsightly by then, but I keep on chopping off those diseased lower leaves. I have organic produce at least :).

Linda

There used to be all kinds of options for residential use of soil fumigants. Unfortunately, they killed more people than bacteria. Solarization is always an option, though if you're not in a hot place with loads of sun, that's unlikely to be effective. I've heard about people doing drenches of their beds with bleach and or peroxide. Properly diluted, a gallon will go a long way. That will kill all your good soil bacteria, but they'll repopulate pretty quickly. So if you have one problematic bed, that might be an option.

But your septoria didn't follow your tomatoes. If it's all around, it's likely endemic.

I am considering solarization, although I really hate to lose my strawberries and rhubarb. I planted them 3 years ago and next year I can finally get a crop I can do something with. They are right next to each other. It probably won't do a bit of good to solarize the part of the bed that has the tomatoes and leave the strawberries (that are infected) right next to it alone, huh?

Have you tried thinning/pruning out some of the thicker foliage in the center of the plants? This year I went out once a week, and thinned the foliage. Had a little septoria early, but nothing too serious. I also alternate spraying with Daconil and copper. Last year my plants were toast in June due to disease and bugs. This year they are still in good shape, albeit the fruit has stopped setting due to heat and humidity. Still getting a few stragglers though. Imo the pruning made a big difference.

To the OP, PLEASE do not cross-post to a FAQ. For some bizarre reason it makes responses to your post invisible to everyone. The responders can see their own responses, but not others, and you probably can't see any of them either. Houzz support has to step in to de-cross list when someone complains. I did. That's why these responses from 8 hours ago just appeared in the last few minutes. They fixed it.

Find the spot in your garden with the most morning sun. Very important against septoria. Then prune to one stem for proper airiness (actually that is not very effective against septoria as it is against late or early blight). Spray if these fail, copper octanoate should be good as preventive.

Thanks for all the advice! Dan - thanks for the tip - I didn't even realize I'd posted to FAQ but now I know not to cross-post there.

Sounds like management is my only real option (but at least I can save my strawberries!). I was afraid you'd all tell me that. HA! Part of my problem is that I buy nursery tomato plants instead of growing my own from seed, which means the plants are tiny and there's no way to trim the lower leaves before planting. This year especially, the plants got septoria as soon as I planted even though I sprayed the new plants AND soil with copper fungicide at planting. In addition to all the suggestions here and on other posts, I think next year I will grow my own from seed, starting early so that I can plant bigger plants and thus would have enough foilage to trim all the lower leaves at planting. I may also add daconil to the rotation, especially at planting.

Unfortunately, I can't put them where they will get morning sun. Not an option for me. They do get blasted with sun though from around 11am till 8pm in the summer months.

Wondering if I should I remove the mulch in the area where I will plant tomatoes for the late fall/winter?

I will change my attitude and keep reading about management of this pesky spore - thanks all!

Interestingly, septoria doesn't live in the soil, though it may survive on organic debris that is mixed in with the soil and not composted. So one piece of advice for bed preparation is DEEP tilling. Make sure the infected debris on top doesn't stay on top. I think fungicide doesn't actually kill the spores, but just keeps them from germinating. So spraying the soil with fungicide may not help a lot, and regular spraying of the plants is necessary.

• Regular spraying from plant out is your only hope to combat the disease.

• I have a buddy of mine that grows for his own CSA program, and he swears by this formula. I have seen his plants over the years, and they always look better than mine. I should start giving it a try. I believe he also throws in 2 aspirin per gallon too.

• What I use for a blight mix per gallon is..

• 1 heaping tablespoon baking soda (About 2+ tablespoons)

• 1 light tablespoon clorox

• 1 light tablespoon Murphy's Oil

The last (3) years, my tomatoes have been devastated by Septoria.

This year, I was determined to go strictly Hybrid. This seems to have helped, though I have lost one plant to what looks like Septoria.

The other plants are pretty clean.

Then you have been quite fortunate or perhaps the weather has been more cooperative this year. Septoria doesn't care whether a plant is a hybrid or an OP. ;-)

Dave

Yes I have Septoria worse in my Hybrids than my Heirlooms.

Seriously ... in past year's beds of Heirlooms, Septoria would have all but put my vines out of commission by now.

But I've got Big Boy, Big Beef, and Celebrity vines, which, although affected by Septoria, are holding on much better than the varieties I've grown in the past.

The infection is there, ... but it is progressing a lot slower (i.e. long enough for me to harvest tomatoes) ...

if you don't mind cheating on being 100 per cent organic diaconal works pretty well . mulch helps but be careful which mulch ,I use landscape cloth between the rows and straw between the plants. I can say some cultivars are less prone to septoria, big beef beefy boy,alot of the oxheart and potato leaf heirlooms. I haven't tried serenade yet. copper is effective if its power mix a little hydrated lime with it ,I t coats better plus a little organic liquid soap.

I have only heirlooms this year. It seems Septoria is more severe on San Marzano, and other cultivars with lots of leaves. Potato leaf cultivars are holding better so far.

used copper once as wasn't sure it is Septoria or bacterial spot. Now planning to try oxidate (home garden version) as eradicant, and switch to Daconil as protective after. Copper seems burnt the plants a bit.

what diaconil does is protect the top of the plants and the un infected leaves. i find it affective. but in between i like to give a mild soap spray, i use peppermint castille soap. works well on ants and small insects.

ps can you explain what you mean by oxidate?

What's "diaconil"? You mean Daconil? That works, and I use it, but I'd find it hard to believe that it would be considered "organic". I use it with some care.

thats it pardon the mispelling.no its not organic but it seems to be pretty benign, . copper can be poisness too plus there are deadly organics also.so i just use it with prudence,

Oxidate for home gardens - https://www.biosafe.net/shop/lawn-and-garden/biosafe-disease-control/

haven't use it yet, just got it from Amazon

i have read reports from Tomatoville where people used a diluted chlorine bleach as an eradicant on their veggie plants and wanted to try. However, I dont trust home remedies and started to search for a commercial equivalent.

The closest I found was the diluted Oxidate from above.

still don't see such a disease pressure to give it a try. Temps are going down, nights are in mid 60, rains seems too.

I also have my reservations with copper - more and more reports on resistance. And I cannot figure out yet how to use it properly to get all the benefits w/o hurting plants.

Daconil seems as effective and much easier to use but doesnt have anti-bacterial properties. So I am using Serenade and DoubleNickel (another antibiotic) with Phosphorous Acid (Exel LG) as a bactericide. Seems plants love the concotion.

We have a very wet summer this year. Usually, I can get away w/o spraying till mid July. And then use only Daconil before rain. This year it is raining non stop since April.

Re Daconil, yes, it is pretty benign, but it is also a recognized mild carcinogen. I wouldn't drink it or take baths in it. Also, I had a bad experience with it very early this year. I mixed a batch *without shaking the concentrate well*. The active ingredient tends to separate from the carrier in Daconil and, boom, I ended up spraying highly concentrated Daconil on my tomatoes. They survived, barely. Always, always, shake your Daconil. Even mixed in my sprayer, I always give it some shakes before spraying.

Interestingly, Daconil is not completely a fungicide, though it acts like one. Although there is chlorthalonil in it that is a generic fungicide, killing fungus where the clorthalonil lands on the plant, the main ingredient in Daconil activates natural production of proteins in all the plant foliage that resist fungal infections.

Fructose is cancerogenic too, and many, many other things. Anything that could trigger a rapid cell turnover, even common colds...

Oh yes, LOADS of stuff is mildly carcinogenic. I am not an "organic" gardener, since I'm not viscerally afraid of chemicals. I am a "safe" gardener, in that I just pay attention to MSDSs, LD50s, and environmental effects. Loads of "organic" stuff is deadly poison.

But yes, taking a bath in, or consuming large amounts of fructose might not be a good idea either.

There are many great suggestions here, but as digdirt2 said - there is no way to eradicate this obnoxious pathogen. I have always found genetic resistance to be a less frustrating approach than attempting to "fight" or "prevent" a disease (whenever possible). Don't get me wrong, I grow OP heirlooms first and foremost, and am resorting to grafting to escape my wilt issues, but that's a whole different story lol.. With that being said, there is a new variety out that touts resistance to SLS (Iron Lady)! That would be my first approach if I were in your shoes, as it would guarantee me a harvest from at least one variety.. Good luck! Iron Lady

This year, I planted Midnight Snack cherry/grape tomatoes, Mr. Stripey heirloom tomato, ... and Big Beef and Parks Whopper hybrid tomatoes.

The Midnight Snack and Big Beef tomatoes grew and fruited well, ... while the Mr. Stripey and Parks Whopper succumbed to fungal disease.

I saw slight signs of Septoria on the more successful tomatoes, but the plants were able to shrug it off ... and go on to perform well.

And the plants were all together and all got the same care.

I continue to recommend Big Beef tomatoes to avoid Septoria devastation ...