Despite the severe damage to its leaves, this plant is still producing fruits that look normal.
Almost all the big tomato plants have exhibited a certain amount of leaf-curl and distortion, but some have fared better than others. In this next photo, notice how the plant in the center looks very normal, whereas the others ("Black from Tula", left, and "Caspian Pink", right) have a lot of damage, particularly leaf-roll on the lower leaves.
The center plant is "Primabella", one of the new blight-resistant varieties. Maybe it resists weedkiller better too? My only complaint about this variety is that it took ages to produce any flowers. The first truss is about halfway up the plant. For that reason I'm letting one of the big side-shoots develop when I would normally pinch it out. This might boost the amount of fruit I get from it.
Here's a contrast in styles: the little one on the left is "Cherokee Purple", and the one on the right is "Costoluto Fiorentino". The "Cherokee Purple" is very much smaller than normal (I've grown it for the last 3 years), but curiously it is one of the most advanced in terms of its fruit - you can see a couple of big ones on it already. The "Costoluto Fiorentino" is completely different - a big, strong plant with masses of leaves, but the fruit is only just beginning to set.
In the center of this next photo is "Ferline", another regular of mine because of its blight-resistant qualities. Ironically it has been one of the worst hit by the weedkiller problem. You can perhaps see that even the new leaves appearing at the top of the plant are twisted and curled-in.
A couple of days ago I thought I detected the first signs of blight on my "Maskotka" bush tomatoes.
"Maskotka" - gone wild!
Can you see the dark patches on the stems in the photo below? This is what I suspect(ed) of being the signs of blight. I'm still not sure, and the leaves, though pale, look OK still. It may just be natural colouration.
Anyway, it seems highly likely that blight will strike at some stage, and probably soon, judging by the warm humid weather, so I have taken a few precautions.
First, I have moved one of my two "Ferline" plants (blight-resistant, allegedly), round to the front of the house. My reasoning is that if the plants at the back of the house get hit by blight, this one might just escape it. Furthermore, its relocation has allowed me to move the other plants just a little further apart, which will improve air-flow.
Second, I have put back into the plastic greenhouses the plants I am growing from side-shoot cuttings. They are not huge yet, so they fit well enough:
My reasoning here is that since the spores of blight are air-borne, the greenhouses may shield the plants from them to a certain extent. Not completely of course, because if I close the flaps on the greenhouses they get very hot indeed - 45C on a sunny day. If the big 1st-generation plants succumb to blight, maybe these little ones will develop in time to give me at least a small late-season harvest? I'm still not sure they will develop quickly enough to produce ripe fruit before Autumn.
There's little else I can do at this stage but wait and see. If I notice signs of blight I will try to minimise the damage / slow its effect by cutting off affected foliage, but once blight gets into the stem of a plant it's pretty much doomed. Even the ones deemed to be blight-resistant will succumb if infected, just not as quickly!