They look to me like theyve been burned by whatever you sprayed on them. Im no expert by any means, that is just a guess.

Emma

Actually, they were doing this long before the spray.
It's not accelerated it on the ones that were already affected, and the tops of all of my plants are healthy and still green.

???

Shankins, I don't see too well, but is that ground cracked? Are they getting enough water and light? I have too much yellowing also, mine started before they were planted. I think some of my problem was from having to hold them too long in the flats. I had a very crazy spring.

Larry

Sharon,

I don't know what it is. My heart says it has to be something fungal, but that is just a gut feeling. However, it also could be nothing more than the normal aging of a maturing plant.

It is normal for older leaves at the bottom of the plant to yellow and drop off over time. This is because the plant is continually pushing nitrogen to the new growth so it will thrive and continue to produce foliage and fruit. It also occurs because heavy upper foliage shades the lower foliage, denying it sunlight either partially or completely. So, that part of the yellowing foliage sounds typical. I don't necessarily see any spotting that I recognize as a bacterial or fungal disease, but then I would only recognize something my plants have had and something that has been identified for me in the past. To get an accurate diagnosis, you need someone trained in disease diagnosis.

When you have heavy rainfall over a period of weeks, the ground can stay too wet and this can interfere in the ability of the roots to take up nutrients. In a case like that, you can see a lot of discolored foliage resulting from a lack of nutrition. If you have fed the plants in the last couple of weeks, though, then this likely is not the reason for the yellowing leaves unless you've had at least a couple of inches of rain in the same period.

If the yellow leaves start low and continue to progress upward on the plant, that seems to me more like normal aging of a tomato plant. However, if the yellow leaves do not necessarily start at the bottom but just start appearing randomly, it likely is a disease issue of some sort.

You likely could call or email your local agriculture extension office and send them a photo for a diagnosis. As much rain as y'all have had there, I can't help thinking that if you are seeing this on your plants, so are many other people. In many county's the extension agent's office has a hotline or help desk staffed by master gardeners. Or, you can take a leaf (in a vase like a cut flower) and a photo to a reliable nursery and see if the staff can tell you what it is and what you do to treat it.

If those were my plants, I'd pull off each and every affected leaf, feed the plant with a water soluable liquid plant food to see if it responded to the feeding by putting out new green growth where the yellowing leaves had been, and then if new yellow leaves continue to appear, particularly in places other than from-the-bottom-up, I'd spray with a fungicide.

Maybe Jay will know what it is or maybe someone else has had this pop up on their plants and can tell you what it is.

My plants often yellow from the bottom up as the summer goes on and I just remove the yellow leaves and carry on. I know from experience that much of the yellowing is normal, though it is not so normal if I start seeing the brown spotting with concentric rings that is associated with Early Blight. I don't expect my plants to look perfect all summer. The excessive heat, wind, insect pests, and minor foliar diseases make them look progressively worse as time goes on, and I don't really care what they look like as long as they are producing tomatoes. Our climate is really tough on tomato plants, and remember too that merely the act of bearing fruit and maturing it is stressful as well.

There also is a chance the yellow leaves could be a symptom of a bacterial or viral disease, but I don't know which one. I cannot see the kinds of spots or specks on the leaves that indicate either bacterial speck or bacterial spot.

Look closely at the yellow leaves, especially anywhere that there is a tan or brown patch. If you see tiny spots or strands of fungi or mold on the upper or lower leaf surfaces, then it is more likely to be a fungal disease than just the aging of the lower leaves alone. However, I know from experience that some of the yellowing is the maturing of older leaves. I think it likely you have at least two things going on with the plants--aging of the lower leaves and some disease caused by the perpetually wet weather you've had this spring.

I think there is a good chance that picking off the yellowing leaves and feeding the plant will put an end to it since you say it isn't accelerating. By mid-summer, I will have removed enough yellowing foliage that the bottom two feet of each plant will look naked, but the rest of the plant will be fine and will continue to produce. That's pretty typical. Other plants also have their lower foliage yellow as time goes on...beans do this, for example, and you often see it on pepper plants, though not as often with them as with tomatoes. Sometimes with tomato plants, you have several things going on at once and I feel like that is what your photos show. It can be hard to distinguish normal age-related yellowing from a disease, but if the plant continues to put out new growth, to bloom and to set fruit, I just don't worry about yellow leaves. I do remove them because I don't like looking at them.

Dawn

Larry and Dawn - thanks; I posted a "group response" on the main posting...Sharon

Sharon I read this post and looked at the pictures last evening when I came in from planting around 10. My first thought was natural aging, lack of air flow or a combination. But after I looked more closely I saw your foliage isn't that heavy and your plants are fairly open. And it appears the yellowing has advanced a ways up the Delicious plant. This led me to think it was probably something either caused by humidity and/or wet soil or a combination of the two. And everyone knows I haven't had much experience with wet or humid conditions in several years. So that along with having several things to do convinced me to wait and see what Dawn posted. I agree with her post. I have seen the yellow leaves like you have but not advancing up a plant that far. I feel it is probably a combination of things. I haven't looked at my marked sites for diseases yet but can't remember anything that covers what your pictures show. Like Dawn said I would cut off all affected leaves. I would probably feed with a good foliar feed that isn't real high in N and watch them. Jay

Thanks, Jay - this is kind of a crazy thing! Tonight I'll trim every last affected leaf off :( feed and spray and hope for the best. I noticed that I'm having axillary budding on some of the plants, right where the leaf is yellowing and about to drop off. I'm thinking that's a good thing and the plants are healthy enough to attempt recovery :-)
Either that, or it's a last-ditch effort before certain death, haha.
Gardening!

Sharon