The Chiloé Archipelago is home to a wide variety of potatoes. After the Titicaca region of Peru and Bolivia, it is the geographical nucleus where the most different types of potatoes are found. Evidence ranging from historical records, local agriculturalists, and DNA analyses strongly supports the hypothesis that the most widely cultivated variety of potato worldwide, Solanum tuberosum tuberosum, is indigenous to the Chiloé Archipelago, and has been cultivated by the local indigenous people since before the Spanish conquest. Unlike potatoes from Peru and Bolivia, the potatoes of Chiloé are adapted to the long summer days of the higher latitude region of southern Chile. After the disastrous European Potato Failure in the 1840s, strains originating in the Chiloé Archipelago replaced earlier potatoes of Peruvian origin in Europe.

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. Early blight, caused by Alternaria solani, is also often called "potato blight". Late blight was a major culprit in the 1840s European, the 1845–1852 Irish, and the 1846 Highland potato famines. The organism can also infect some other members of the Solanaceae. The pathogen is favored by moist, cool environments: sporulation is optimal at 12–18 °C (54–64 °F) in water-saturated or nearly saturated environments, and zoospore production is favored at temperatures below 15 °C (59 °F). Lesion growth rates are typically optimal at a slightly warmer temperature range of 20 to 24 °C.