Yes! This is what's happenning to me also. I got on here tonight to post a question about it. My experience is exactly the same as Teresa's. It looks most like the picture of Canker on the Problem Solver/Leaves pictures but there appears to be nothing wrong with the leaf stems or the branches (no canker.) I have early blight on other plants so I know what that looks like, but this one is new to me.

Any help out there?

Teresa and Lizzie,

There are two diseases with Canker in the name.

One is Bacterial Canker which can be found almost anywhere in the US but ususally more southern than northern, and is characterized not by necrotic lesions on the leaf margin, but by many other symptoms such as dark lesions on the stems, wilting in a certain pattern, fruit infections with specific lesions, etc.

The other one is Alternaria Stem Canker which has leaf lesions that are nothing like what is shown here as well as other symptoms and is found almost exclusively in CA.

I have leaves with necrotic edges as well, and as long as there aren't any other symptoms I ignore them and usually new foliage is fine. I chalk it up to weather, whether I'm right or wrong.

Carolyn

Well Carolyn, I will surely heed your advice. I too felt the lesions were like nothing I'd seen associated with EB or bacteria but was unsure what to do. It does, however, appear to be spreading which gives me pause. I'll try to remove as much of the dead tissue as I can and keep the fingers and toes crossed. As always, thanks a bunch.

Teresa

Teresa, what was the outcome for those two plants? Did it spread to other plants? I have 18 varieties started, mostly between 6-12 of each and of those I have one variety 'Hawaiian Pineapple' that has a similar problem to the one you posted about. It started with the cotyledons. There is only one other plant that has this problem and it is a cross (not all the seedlings from that cross, just one plant). I'd like to get some advice on whether I should dispose of the plants with the leaf disorder. If it could spread, it's not worth it. See pictures.

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Here are the pictures that should have been above. Also, forgot to note that the leaf disorder appeared on the cotyledons before the first true leaves emerged, so well before I used any fertilizer. I'm now using Alaska 5-1-1 and 0-10-10 TBSP of each per gallon. My seed starter mix is Promix PGX

Some tomato genotypes show this sort of marginal burn on the cotyledons and leaves when germinated and grown in artificial soil mixes. Once you transplant them out to the field in real soil, the burn symptoms go away on the new foliage. The post above by gringojay gives some insight into what may be going on with the plants. This is a physiological disorder rather than a pathogen caused disease.

I too have similar problem to one of my plants .
Early girl tomato around 2 months old, started flowering.
Using a miracle grow soil in a 5 gallon container.
Hardening zone = 10.
Bottom two branches are affected by this. Other tomato plants are not affected. Please help

I'm having the same problem as well. Did the hydrogen peroxide work? Or does anyone have additional advice?

This sort of thing seems to be an issue with water (too much or too little), or it could be from too much fertilizer or some kind of osmotic issue in the roots. My hypothesis is that it happens more in seedlings and then gets outgrown because seedlings are delicate and have underdeveloped root systems and are more susceptible to even minor water related stresses. If it's happening in a bigger plant, it's usually in a container or in soil that has draining issues. Disease can have marginal necrosis like this as a symptom, too, but there are usually other issues such as yellowing, spots/lesions, etc.

Is the potting mix you're using compacted, or are your plants rootbound, i.e., are the containers now too small for their roots?