Pics are out of focus so it is difficult to determine a specific and there are at least 3 possibilities - 1 bacterial and 2 fungus-based. Given the wood chip mulch in your photo then one of the common fungus diseases such as Early Blight is the most likely - yet another reason for never using wood chip mulch around vegetable crops.

But all of them begin with the same basic treatment - strip off all affected foliage as soon as you see it and dispose of it away from the garden - never leave leaves such as this on the plant - and if you haven't already been using a regular weekly fungicide spraying program, start it ASAP.

Fungus diseases can't be cured, only prevented by spraying fungicides from day 1 of planting. Once they take hold, the goal is to slow them as much as possible. Daconil is the fungicide of choice but which you use is up to you.

Good luck.

Dave

PS: see the site below for many different photos to compare to your plants directly in the hopes of narrowing it down.

Here is a link that might be useful: TAMU Tomato problem Solver

And I thought I was doing a GOOD thing with the mulch because it would help conserve water! I am pretty sure it is early blight now, too. I hate to sound so dumb, but can you purchase the Daconil at Home Depot, Lowe's, etc.? Thank you for your help!

Mulch is a good thing - just not wood chip mulch. Straw, hay, grass clippings, cardboard, shredded newspaper, shredded leaves, leaf mold, compost, etc.

Yes Daconil is available at Walmart, Home Depot, Lowe's, Ace Hardware, etc. The same stuff is also sold under the name Ortho Garden Disease Control.

Dave

Thank you, Dave. I went back outside after your first note and removed every leaf/stem I could. I am going to go buy some fungicide tonight and put on tomorrow. Hopefully, I can get it under control enough to get a decent crop this year.

Sorry to be a pest, but at the end of the season, when I rip everything out, any suggestions for overwintering? Should I till the mulch into the soil? Or move as much as I can out? Anything to put on the soil to "treat" it? Just trying to think ahead to avoid this issue next year.

at season end, pull out all tomato plants and dispose of them away from the garden. Next year, make a point of planting a non-solanum in the area that has tomatoes now. An example that works would be to follow tomatoes with beans or better yet with corn. You can rotate back to the same area with tomatoes every 3rd year without causing significant disease buildup.

BTW, you have both septoria and early blight on those leaves. The treatment is the same.

DarJones

at the end of the season, when I rip everything out, any suggestions for overwintering? Should I till the mulch into the soil? Or move as much as I can out? Anything to put on the soil to "treat" it? Just trying to think ahead to avoid this issue next year.

As Darrel said - dispose of all the plants away from the garden, don't compost them. As for the wood chips, do not till them in. That will bind up much of the nitrogen in the soil for some time as they decompose. Rake as much of it out as possible and put it to use around ornamentals, bushes, flowers, and such.

As for treating the soil, they do make fungicide products for soil application but I have never found them beneficial. Plus they are expensive. And the fungi that cause such diseases are airborne so save the money and use it to buy fungicides for treating the plants next year from day one instead.

Dave

I've got a question on wood for mulch. In Als 5 1 1 container mix he uses 5 part bark fines. Will this too caus tomato leaf issues?

No. Not the same thing. Bark fines are much finer - no pun intended - much smaller in texture and already partially decomposed. Plus they are only a part of the mix and already mixed in with the other ingredients. They are not used as a mulch, not exposed to the air and humidity, so fungi don't grow on them as they do on wood chips used as mulch.

Dave

thanks dave

Thank you, gentlemen. I don't know if crop rotation will work for my garden since I have a very small area (14x14 feet, more or less). We were, however, thinking of putting in raised beds before next year.

I bought some Daconil this evening. Am going out in the morning to spray. I read somewhere to repeat every 7 days. Is that for the remainder of the summer/growing season?

Yes, at least every 7 days. And one should always rotate fungicides betwen at least two different chemicals. Copper, Mancozeb and Daconil is a good rotation. It probably will not totally stop it, but it will slow the disease down enough so that the plant can produce leaves faster than the disease kills them.

That is not Early Blight. It looks like Septoria.
Early blight has oyster shell looking spots. They have concentric rings and are larger. Septoria has smaller spots that look like the leaves have been speckled. The spots are small as in the your pic. They are dark with the centers lighter just like in your pic.
Septoria is a fungal disease just like early blight and is control in the same manner. You will also get it mulch or no mulch. It doesn't matter. If the weather conditions are right, it will appear even if you are growing your tomatoes in pots in a soilless mix.
Remy

Can I mix a copper powdered fungicide with my liquid daconil spray?

Thank you!

Can I mix a copper powdered fungicide with my liquid daconil spray?

No you cannot. You should never mix chemicals as they can both interact and/or nullify each other. Recall high school chemistry class if you will. :)

You can however alternate them in application - Daconil one week and copper the next if you so wish.

Dave

You should never mix chemicals as they can both interact and/or nullify each other. Recall high school chemistry class if you will. :)

I recall a friend's college chemistry class where two mixed chemicals might also explode and wreck the lab....

I tank mix copper with Daconil all the time. The general rule of thumb is if the mixture does not cause a precipitate to form, you are good to go. A lot of labels say just this.

While it is possible to mix several different fungicides, it is usually not the best way to manage diseases. The exception to this is when the two fungicides have totally different methods of working. Daconil is a surface coating that prevents the fungal organism from breaking through to the leaf surface. Copper is poisonous to the fungus. For this reason, mixing copper with daconil can work, they have different modes of effect.

The idea behind alternating applications of any kind of pesticide/fungicide is to prevent resistance from developing. This applies when two fungicides have similar modes of working. so if two fungicides are poisons that kill the fungus, then they should be alternated. Neem and copper would be an example of two that should be alternated.

DarJones

FWIW When I lived in Tennessee we got the same thing on all our tomato plants. I used an organic spray to combat it, maybe something called Serenade? Its in a hot pink bottle.

I was never able to totally do away with the fungus, but the good news was that my plants just kept on producing. But it got to be ridiculous: I had a vine of cherry tomatoes that was, I kid you not, at least 12 feet long, but the bottom 6 feet or more was stripped bare of any foliage. But the growing end of that plant just kept on kicking out tomatoes, bless it.

Bacterial spot.

"I was never able to totally do away with the fungus, but the good news was that my plants just kept on producing. But it got to be ridiculous: I had a vine of cherry tomatoes that was, I kid you not, at least 12 feet long, but the bottom 6 feet or more was stripped bare of any foliage. But the growing end of that plant just kept on kicking out tomatoes, bless it."

haha....this is EXACTLY my experience too!!

If I were a commercial grower and can hire people to apply daconil every 7 days, I may feel differently about this. But since I only have about a dozen tomato plants in a home garden, I just strip off the diseased leaves and do crop rotation. Like what the others said, my plants get some kind of blight every year (no late blight so far thank goodness) and they always give me a decent enough harvest. So for me at least the benefit of using daconil does not offset the risk.

Where does one buy Daconil or copper spray in Ontario, Canada? (for early blight)

Ty

^Look for Bordo Spray...Home Hardware stocks it. Both Wilson and Green Earth have versions of this product.