Little wonder that Highland people became heavily dependent on this crop so when, in the 1840s, blight destroyed whole fields of potatoes, the effects on the crofting population were disastrous. They led to a mass-migration from Scotland to places such as the US, Canada, Australia and New Zealand - see Wikipedia account here.
The blight hasn't gone away. A couple of years ago the last field in Ormsaigbeg planted to potatoes was affected, the Golden Wonder variety suffering worst.
Pat MacPhail has an apartment to let in her croft house, details here.