[Muddylou]

My first earlie's (Kestrel) and second earlie's (Charlotte) are doing well, deep green tops and some flowering, most of my main crop (Roma) are also looking fine.
My problem is, three of  my Roma plants were turning yellow with brown spots on the leaves. I panicked and asked one of my neighbours (he's had a plot for 36 years) what was wrong, he replied that I had a "bit of blight" due to the weather. On asking what I could do about it , he said pull the damaged bits off, which I did (I pulled the stem off and put into a bin liner then a skip) .

     I remembered reading a post saying that lack of nutrients also led to problems, so I fed them and everything seems fine except for the three original plants. They are slightly yellower than the rest.
 
     This all happened three days ago, my questions are,

1) If it's blight would my other potatoes be showing signs as they are only a yard away from the mains.

2) Would my other mains be showing signs (they aren't).

This my first time growing pot's and obviously don't want all my neighbours hating me for destroying their crops        
           

[Janeymiddlewife]

As I understand it there is "early" blight which is not so severe that's probably what your spuds have - it's the late blight which is already in some places that spreads like wildfire. You can't stop it from spreading, chances are if you had blight so would most of your neigbours as it's airborn. It finished off my tomatoes last August - never got any as i was away and neighbour didn't bother to pick any 
Some varieties are more resistant than others, you can also spray at the first sign which may delay or prevent it if you are thorough and don't mind using sprays. Otherwise you can try removing the foliage, cutting the haulms down to the ground and leaving the spuds in the soil for a while - personally I'd check a few first though as if they're already affected you might as well dig up the lot and burn whatever is not usable - DON'T put it on your compost heap, then if it is in the soil don't grow spuds on there for at least 3 years!  There is a blight checker here:-http://www.potato.org.uk/fab_blightwatch/index.html   (sorry I'm not sure how to post links)
Good luck, fingers crossed

(did the link for you)

Thanks peapod!!

[Muddylou]

Thanks Janey,
                    I'll do just that and I won't put the tops on the compost. 

[Gwiz]

We've had something simular on our allotments.
We had it checked out by Wisley, and it turned out to be "stress" due to the very dry weather.
A lot of my spuds have got it (earlys/second early) We've dug up the worst affected ones, they were lovely