Potato blight also affects tomatoes, especially those grown outside.
Tomatoes can be given some protection by spraying with Bordeaux Mixture. This is less practicable with potatoes unless you only have a few. The best thins to do with pottaoes is to keep a close watch on the foliage and, if you see the first blight damage, remove ALL THE FOLIAGE TO GROUND LEVEL. This should be burned or put in household rubbish, not composted. The potatoes can then be lifted at the earliest convenient time - ideally within a fortnight.
Potatoes which have had a brush with blight will store better in canvas sacks than in paper ones, as the circulating air retards the further growth of any blight fungus.