Not sure exactly what it is, someone else might be able to help with that. But I've had the same on mine from time to time. I usually remove any affected foliage and begin spraying with a fungicide, and that usually stops it if I catch it early enough. I use Daconil, but you might get some other suggestions. Too much water won't improve the situation, so don't overwater at this point.

I can't really tell for sure from the photos but my best guess would be 2 things - Septoria Leaf Spot in the middle pic and some nutrient deficiency issues too, primarily based on the interveinal chlorosis.

It it isn't Septoria the odds would favor Early Blight and the treatment for both is the same - strip off all the affected foliage and begin a regular spray program with Daconil fungicide. I would also spray the plants not showing symptoms to help prevent further spread as they too are likely affected.

As to the nutrients, the source you are using isn't a commonly used one and has a couple of drawbacks, primarily that it is a very inconsistent supply heavily dependent on soil moisture levels. Many other more effective supplements are available, especially for in ground growing.

Hope this helps.

Dave

Well, I was afraid it might be something like that. I had looked online at photos of different tomato problems but none matched exactly. The whole park's whopper plant looks like that so I guess I will have to pull it. I will also check the other plants thoroughly and remove anything that looks like it and follow up with Daconil. How often do you have to spray it?

It is just so unusual for around here, usually we don't have any problems with things like that, that are caused from humid conditions. Is moisture the only cause of these diseases? I spent a little time reading about them and it seemed like everything I saw said it was caused by hot, humid conditions. Do you have any suggestions or tips on how I could prevent this from taking hold in the first place? I did everything that I have always read to do to prevent problems. I have all the tomatoes caged and up off the ground, I do not overhead water, and the ground is covered with mulch, I try to rotate my veggies as best as I can. We live in an extremely hot, dry climate and have had very little rain. I usually have more problems with spider mites than anything else, lol!

Also what fertilizer would you recommend? I have read about so many different fertilizers and ways to do it that it makes my head spin! I need to get my soil tested this year, but is there anything that is just a general fertilizer that I can use until I get it tested?

Thanks for your help!!

Carly

I would do as Edweather said: clean up the yellowed leaves and give them a good soak with some fungal spray (neem oil, Daconile ... ).
In the first picture, appears to ME that the leaves had gotten sunburn and subsequently died and dried up. Yellowing is just normal course of dying and I don't see a typical concentric rings there.

I trim any lower leaf as soon as I see one getting yellow. In that condition that leave is just a burden on the plant and might harbor disease.

I first posted this a little over a month ago. Since that time I have removed all the affected foliage and sprayed with daconil. It didn't help and this just kept spreading so I started pulling plants. Finally, today I pulled one of the affected plants and took it to my county agent to see if he could tell me for sure what it was.

He said that it is tobacco mosaic virus(which is not what I expected!) I have spent the last hour doing some research on it and it does look exactly like what is going on with my plants. Then I came here and did a search for it to see if I could find any more info and found several posts in reference to it that stated that TMV was practically non-existent in the US.

So now I am confused! Does my county agent know what he is talking about or is there some small chance that this is actually TMV?

Also if anyone can recommend any good TMV resistant varieties or other suggestions I would greatly appreciate it!!

Thanks,

Carly