Ireland begins to experiences failure of the…

Ireland begins to experiences failure of the potato crop in 1841, by which time almost one-half of Ireland’s population of eight million, two hundred thousand—but primarily the rural poor—have come to depend almost exclusively on the potato for their diet, and the rest of the population also consumes it in large quantities.

A heavy reliance on just one or two high-yielding varieties of potato has greatly reduced the genetic variety that ordinarily prevents the decimation of an entire crop by disease, and thus makes the Irish potentially vulnerable to famine.