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Cryphonectria parasitica is a parasitic fungus of chestnut trees. This disease came to be known as chestnut blight. Naturally found in South East Asia, accidental introductions led to invasive populations of C. parasitica in North America and Europe. In the first half of the 20th century, the fungal disease had a devastating economic and social ...
Chestnut blight affecting a young American chestnut. The appearance of invasive pathogens of the American Chestnut into the eastern deciduous forest ecosystem is just one instance of the Columbian exchange of pathogens. While the Columbian exchange moved valuable crops between the Americas, Europe & Asia, there was also a downside, as the rapid ...
Pathogens can spread through the air, water, or on insect and animal vectors (hosts). Dutch elm disease was spread by elm bark beetles, yet the tree mortality was caused by a pathogen. Chestnut blight is a fungus spread through wind dispersal and rain splatter; the blight traveled up to 50 miles in a year by natural means.
Struck by a blight identified in 1904, American chestnut trees are considered "functionally extinct." Now those that remain are facing a new disease.
The mission of The American Chestnut Foundation (TACF) is to restore the American chestnut tree to the forests of Eastern North America by breeding genetically diverse blight-resistant trees, evaluating various approaches to the management of chestnut pests and pathogens, and reintroducing the trees into the forest in an ecologically acceptable manner.
Relative to a susceptible plant, disease resistance is the reduction of pathogen growth on or in the plant (and hence a reduction of disease), while the term disease tolerance describes plants that exhibit little disease damage despite substantial pathogen levels. Disease outcome is determined by the three-way interaction of the pathogen, the ...
Oak wilt is one of three devastating North American vascular wilt diseases that appeared in the early 20th century. The other two vascular wilts are chestnut blight (1900–1950) and Dutch elm disease (1928–1980). Each of these diseases have depopulated their respective host tree populations.
In the 1970s, geneticist Charles Burnham began back-breeding Asian chestnut into American chestnut populations to confer blight resistance with the minimum difference in genes. [63] In the 1950s, the Dunstan chestnut was developed in Greensboro, N.C., and constitutes the majority of blight-free chestnuts produced in the United States annually.