Is this Early Tomato Blight?

[MarkPelican]

I know that Blight is a perennial question and I've always had difficulty working out whether something is early signs of blight or something else entirely. However, one of my tomato plants has started showing this:

I'm particularly interested because this is an F2 of Mountain Magic a hybrid which is supposed to be Blight Resistant. I saved seeds a couple of years ago and this is the first time I've seriously tried to grow them again. I've ended up with two very different types of plant, one is Potato Leafed and the other (this one) regular leafed. From what I've been able to find about this hybrid it was developed by North Carolina Agricultural Research as a hybrid of two varieties, one of which gave resistance to Early Blight and the other resistance to Late Blight. If (and its a big if) this IS early blight, then I don't want to touch it with a proverbial bargepole.

[burnie]

It does look like it, is there any signs on the stems of the plants as well as the leaves, if there are any fruit, do they look damaged as well?

[ameno]

That does indeed look like early blight, but early blight is not the same disease as late blight. It's completely unrelated, in fact.
Late blight is the dreaded "blight", whereas early blight is rather less severe. It's not very common in this country, for starters. It usually favours hotter conditions. And it is usually not fatal and does not usually infect the fruits (although it can do in a severe infection). My early potatoes in pots last year got early blight. It never progressed very far, and the yield was unaffected.
For the time being, I would remove only the infected leaves (bin or burn them) and see how things go.

[MarkPelican]

Ameno/Burnie I've cut off the affected leaves & binned them. With early blight I wouldn't expect the stems or fruit to be affected.

What's interesting (to me anyway) is the fact that no other tomatoes around the infected plant seems to have a problem and the specific cultivar is a descendent of an F1 hybrid which is supposed to the blight tolerant. I'll keep an eye on it and see if it re-occurs.

I was only growing it out of interest. I found that these varieties do get late blight (at least when grown at my allotment) although not as badly as non-blight tolerant varieties. They didn't taste the best either.

My understanding is that the crop might be affected. I don't think I'll grow them again even for fun.

[Jungle Jane]

The blight resistance in the F1 hybrid won’t follow onto the next generation of seeds,how are the genetics of the seed changed to give it blight resistance,would you need to isolate the resistant gene & introduce it to the plant cells in a lab with a petri dish? It could be neither plants have the gene but that might not be blight,it doesn’t have the concentric circles,hopefully it’s not blight.

[MarkPelican]

I know that the F2 probably wouldn’t be blight resistant. What intrigued me was that it is the only plant affected in a whole greenhouse.