Chestnut blight

The chestnut blight is a fungal desease, Cryphonectria parasitica (formerly Endothia parasitica). It was accidentally introduced to the United States around 1900-1908, either in imported chestnut lumber or in imported chestnut trees, and by 1940, the American chestnut had been made virtually extinct by the disease.

The blight appears to have been introduced from either China or Japan. Japanese and some Chinese chestnut trees are resistant to the fungus: they may be infected, but the blight does not usually kill them.

Also see:
http://www.ppws.vt.edu/griffin/blight.html