Within 40 years the nearly four-billion-strong American chestnut population in North America was devastated — only a few clumps of trees remained in California, Michigan, Wisconsin and the Pacific Northwest.
Okužba ameriškega kostanja s "C. parasitica" se je istočasno pojavila v številnih mestih na vzhodni obali, najverjetneje iz Castanea crenata ali japonskega kostanja, ki je postal zelo priljubljen uvoz.