Diseases of chestnut trees

American and European chestnut forests have been heavily impacted by two epidemics, caused by pathogens originating in Asia that coevolved with Chinese and Japanese chestnut. In the USA and Europe, these pathogens encountered a favorable environment, very susceptible naïve hosts, and few natural enemies. Chestnut ink disease, caused by Phytophthora cinnamomi and P. × cambivora, which have spread throughout the range of American and European chestnut trees, is one of the earliest known pandemics of forest trees. The second pandemic was chestnut blight, caused by Cryphonectria parasitica, which also spread around the world. The main control methods for these diseases are based on sources of resistance (Asian chestnut trees) and hyperparasites (mycoviruses also originating in Asia). However, American and European chestnut trees are not safe from new threats linked to global change (introduction of new pathogens, climate change, etc.).