The (possible) end of nanas

[Ranger]

Unfortunately this is what happens when you put all your eggs into one basket. As for the potato blight, I'm sure I can recall a program from a few years ago (may have been a Countryfile or something similar) where they did a report about a couple running a farm in Northumberland who grow all different cultivars of seed potatos on their hill farm because the blight cannot survive above a certain elevation above sea level. This farm is then acting as a reservoir of healthy plants in case there is another large scale blight problem.