‘Blight’ warns that a future pandemic could start with a fungus

Blight
Emily Monosson
W.W. Norton & Co., $28.95

In the summer of 1904, American chestnut trees in the Bronx were in trouble. Leaves, normally slender and brilliantly green, were curling at the edges and turning yellow. Some tree limbs and trunks sported rust-colored splotches. By the next summer, almost every chestnut tree in the New York Zoological Park, now the Bronx Zoo, was dead or dying. By around 1940, almost every American chestnut across its native range, the eastern United States, was gone. The trees had been felled by a microscopic fiend: Cryphonectria parasitica, a fungus that causes chestnut blight.