The potato was an important and versatile crop for the country of Ireland between 1700 and 1840. It was a high yield crop producing healthy food with little labor needed. The Irish were “potato people” – they ate everything potatoes. They ate potatoes for breakfast, lunch and dinner. By the 1840s, almost half of the Irish population was entirely dependent upon the potato. It was because of this dependency that the “Great Famine”, also known as the Irish Potato Blight, (which occurred between the years of 1845 and 1852) was able to kill (either through disease or starvation) about a million people. This was because when people are malnourished, they are vulnerable to infections. Many of the infections that ravaged the populace were measles, diarrhea, TB, whooping cough, intestinal parasites and cholera.
It is important to note that the severity of the blight was enhanced due to several other external factors. The first of these was the economic relationship between Irealnd and England. The population in Ireland was increasing and there were exploitations by landowners. There were also enforced exports of food crops to England, which led to further famine. Also, those who were not killed off due to the blight emigrated from Ireland. This dropped its population by 20-25%.
The exact cause of the blight was found to be Phytophthora infestans. Historical samples recently found of the virus suggest that sometime in 1842 or 1843, the ancestor of HERB-1 strain of P. infestans made it out of Mexico and North America and then to Europe. They theorize that it was contained within the potatoes that ships carried as food for their passengers.
HR: all sources provided on CANVAS, https://en.wikipedia.org/wiki/Great_Famine_(Ireland)