Tomato plant stem and leaves turning dark green/black with yellow circles

Question

I have a few tomato plants where the tops of the leaves and stems are turning dark green/grey. Additionally, yellow circles are appearing on the leaves.

These were recently transplanted from indoor containers to a larger garden bed outside and didn't show these symptoms prior to living outside. That was about 1 week ago.

From what I've been able find while looking around this could be some form of blight? My plan was to prune the affected areas and spray with a baking soda solution, but I'm not sure if that would actually help since I'm uncertain what the issue is so far.

I have a few other tomato plants I've transplanted at the same time that don't show any of these symptoms that are in the same soil.

Update I've added a photo of a nearby tomato plant that isn't showing any of these symptoms and was transplanted at the same time. However, I did give this one some bone meal earlier than the others (before transplanting) because I saw the undersides of its leaves and the stem were turning purple. From what I've read that can indicate a phosphorus deficiency.

The bone meal fertilizer I used is 3-15-0.

Answer 1

No, this is not blight. Caused by normal everyday fungus and it is called Shot hole as well as other names. A drop of liquid that happens to have the fungal spores in it splashes upon the leaves. The plant itself manages this fungus by causing the spot to die and fall out leaving a blank hole. Pretty cool.

Definitely no big deal. What I am seeing, however, is that your tomatoes could use some balanced fertilizer. They are in a weakened state and need to get more vigorous and healthy to combat bigger diseases, make more fruit.

What have you given these plants for a balanced fertilizer? Did you take these as starts that you started and transferred them into these pots and did you take them out of doors without acclimating them? The pots are too large for this small of a plant but that isn't the problem. They need fertilizer.

Hopefully, you used potting soil not garden soil in these pots. If so, these plants are doing a darn good job at surviving. Any plant that is planted in a pot has to be planted in sterilized cheapo potting soil. Never garden soil. Planting them in the garden soil after acclimatization is fine.

Just get some Osmocote Extended Release All Purpose fertilizer 14-14-14. Use half of what the directions direct. Less is Best, More is Death but None is Dumb, grins, my little ditty about fertilizer.

Starts need to be started in tiny tiny pots and then upgraded in steps to larger pots. Only potting soil for all plants planted in pots and even planters. Hard and fast rule. No exceptions. Send a picture of the other tomatoes and tell me more details. Is this the first veggie garden experience for you? I'd like to make it more successful!

Answer 2

In your first image in the lower left quadrant there is a leaf with a single black dot on it. This could be an indication of flea beetles. Flea beetles rather like young tomato seedlings. Examine your plants carefully for these small black insects about the size of a pinhead which move quickly but can be caught and carefully squeezed. Check the plants frequently until they grow big. They could be causing the yellow/white circles. Then get some feed into those anemic plants as @stormy suggests.