On an historical note, despite growing-up in Ireland I only discovered recently that the potato harvest failure in the mid-1840s was part of a much wider European famine.
Ireland and northern Scotland had similar levels of per capita potato consumption ( around 2 kg per day! ) which was much higher than the rest of Europe and indicated the monopoly of potatoes in the Celtic diet.
So for the first year or so of the potato failure the other countries were able to shift reliance to rye and wheat. But in 1846 those crops also failed...
Interesting reading here:
The European subsistence crisis of 1845-1850: a comparative
perspective
Ireland and northern Scotland had similar levels of per capita potato consumption ( around 2 kg per day! ) which was much higher than the rest of Europe and indicated the monopoly of potatoes in the Celtic diet.
So for the first year or so of the potato failure the other countries were able to shift reliance to rye and wheat. But in 1846 those crops also failed...
Interesting reading here:
The European subsistence crisis of 1845-1850: a comparative perspective
http://www.helsinki.fi/iehc2006/papers3/Vanhaute.pdf