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Which organism caused the potato blight during the Great Famine?
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Great Famine
Famine (1997), sculpture by Rowan Gillespie commemorating the Great Famine; in Dublin.
The potato blight that caused the Great Famine in Ireland was caused by the water mold Phytophthora infestans.12
While often referred to as a fungus, Phytophthora infestans is technically a funguslike water mold. It was introduced to Ireland from North America in 1845, and because the Irish potato crop lacked genetic diversity, the pathogen was able to spread rapidly during the wet summer conditions of that year, leading to the catastrophic failure of the potato harvest.1