Diseases and insects are among the most serious problems facing farmers who grow potatoes. The Irish potato famine in the 1840s, caused by the fungal disease light blight, was the worst European disaster since the onset of bubonic plague, the Black Death, 500 years earlier. During the famine, a million people died and another 1.5 million emigrated, many to the United States.

A child holding Andean potato weevils, in Carchi, Ecuador.