<human>:  With regards to the Irish potato famine, when did it start and when did it end?
<bot>: The Irish potato famine started in 1845 and lasted until 1852. The famine was caused by a disease called Phytophthora infestans that caused the Irish potato crop to rot. The disease spread quickly because the potatoes were not harvested early enough and the potatoes were stored in the ground for too long. The lack of food and disease killed many people and left others sick.