I'm thinking blight. Mr Stripey is an heirloom and going to be susceptible to every disease there is. I had a frustrating experience with it this year, and it's one of the very few I won't grow again.

If it is blight, you can clip the dead leaves and spray the plant with a fungicide like daconil. That will help to slow the spread of the disease to the leaves that are still green.

Thanks. I've heard that neem oil helps keep blight under control. True or not?

not

The neem oil is for mites. If that is blight, you need a fungicide, like Daconil, Copper, or Sulphur. If you don't want to use any chemicals, you can try a 20% milk and water mixture or hydrogen peroxide.

Umm, milk, water and hydrogen peroxide are all chemicals.

Blight is a general word that many use to describe a sick tomato plant but it's best to be able to ID the specific disease involved if one can.

First, I Don't know where you live which would help narrow down the possibilities.

If it's a foliage disease I'm just noting that there are no varieties, hybrid or OP, that are tolerant of the common foliage diseases, but I don't see any spots on the leaves that would indicate that so please do note if you see any such leaf spots and if so please describe as to size and color and shape and if there are any yellow halos around them. Also if there are any dark colored areas on the stems.

If it's a systemic soilborne disease, such as Fusarium or Verticillium or several others, again, it depends on where you are in a geographic sense, then there's nothing to be done at this point.Even with hybrids that have tolerance to some of the soilborne diseases all it means is a week or so more of growth before the plants go down. There is no such thing as total resistance to soilborne diseases, and the genes that are bred into many hybrids are of best use to large scale commercial farmers who base when they harvest on Brix levels, which is a measure of soluble sugars and the extra few days that tolerance brings can allow for those Brix levels to reach the right level.

It would also help to know if you're growing other tomato plants and if they all have the same symptoms.

Carolyn