Late blight of potato turned into an epidemic in which year?

Late blight of potato turned into an epidemic in the year 1845.
Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight.
The Irish Potato Famine, also known as the Great Hunger, began in 1845 when a mold known as Phytophthora infestans (or P. infestans) caused a destructive plant disease that spread rapidly throughout Ireland.