Better Boy Tomato grown in zone 10a

I showed it at my local garden center, but they said its normal for old leaves. But I think its some disease, as the new growth also gets similar blackening of leaves within weeks. This only happens to leaves that are in touch with other infected leaves. Need help identifying what is the name of this disease and what are the remedies, if any.


EDIT: Adding many pics, the one that shows totally brown plant, is the one which the original image was from. All other images are from another plant which also has the same disease, but I'm making it survive by regular removal of diseased leaves.

The plant which had the leaves from original pic Another plant: this is how it looks from a distance[![][3]]4 [Diseased leaves]5 [Bottom view]6 [New leaves starting to show signs of disease]7 [enter image description here]8 [enter image description here]9 [enter image description here]10 [enter image description here]11 [enter image description here]12 [enter image description here]13

To answer @stormy's questions: - watering practice: 1gallon every 3rd day - soil: I just potted the plants in my backyard's garden soil(which is a little clay-ey). This is in california, zone 10a - fertilizers: i just added the fertilizer once while transplanting the seedlings - epsom salt: I only used it once - tomatoes never became black, as you can see in the pic(even on the totally decimated plant, they were fine)

It was gradual blackening, and i'm very sure it was not in a matter of days. One thing that could have contributed to this was that I never did any pruning before the offset of the issue. I used a 42 inch cage, but the plant was about 4 feet long, and started bending. It became very heavy, so the cage was not sufficient, and I had to use wooden sticks and wool to make it not fall on the ground. Anyways, the gist is, not much air circulation probably.

The original picture that I shared was about a month old, so out of 4 plants, 2 have totally dried out. The remaining 2, I keep pruning leaves which show symptoms of unhealthy leaves, this has helped in reviving the plant, though it is not fully free of the disease.

I'd like to know if this still looks late blight to you, it actually started around August first week I think.

  • Did you fertilize them soon before this happened? I know you mentioned it being contagious, but I think it's good to rule out other possibilities like nitrogen burn just in case it was a coincidence or something. Also, did you overwater or did the temperatures/rainfall change recently? Sep 17, 2017 at 1:50
  • 1
    @Shule: I fertilized only once, at the time of transferring seedlings into ground. My watering schedule was 1gallon every 3rd day. Now I've cut it down to 1.5gallon every 4/5 days.
    – Anonymous
    Sep 18, 2017 at 1:02

1 Answer 1


Looks like Late Blight for tomatoes. Are all your plants blackened like this? Please send a picture of the entire plant. Tomatoes? If this is Late Blight, all of your tomatoes will turn black as well. Bummer. How long ago did you notice this blackening? I remember, in 3 days, every plant I had that had previously been perfectly healthy (70), turned black. I tried collecting some of the tomatoes and those turned black as well.

tomato blight leaves

All it takes is ONE spore that splashes up on the plant and that is a done deal. The spores are in the soil. If you are using an area in your garden (are these plants in the garden or in pots) that you grew potatoes, tomatoes, peppers, egg plant in last year...or the year before, this is where that fungal disease came about. This is the reason for rotation of crops; primarily the brassicas (broccoli, cabbage...) and the solanaceae (tomatoes, potatoes...).

To properly identify this disease we need more information such as what soil has been used, watering practices, fertilizers and a few more pictures.

You will have to pull up all your tomatoes, if this is indeed late blight, and dispose carefully. You should not try any of the solanaceae family in that soil if this is in your garden for at least 2 years. If in pots that soil needs to be carefully dumped, the pots cleaned out with bleach. I am guessing if you used pots that you did not use sterilized potting soil. I now always plant tomatoes and peppers in pots in sterilized potting soil. I cried when I lost this gorgeous crop of tomatoes!

Additional information to ID:

Fusarium crown rot

Leaf Mold

Bacterial wilt and canker

Check out these sites. The last one shows how to cut open the stems. Find a stem that is partly alive to do this with. If your fruit are not blackening I doubt you have Late Blight. As you can see, tomatoes get lots of diseases! But its important to KNOW what you've had. So let's keep working on this. Great pictures, btw!

  • Many thanks for taking the time to reply. I've uploaded more pics to help diagnose better. Also, I have edited the question itself with answers, as the comments have a character limit.
    – Anonymous
    Sep 18, 2017 at 1:50

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