At one time, chestnut trees grew in large numbers across the American east coast. Then, in about 1906 a fungal disease called chestnut blight (Endothia parasitica) was introduced into New York on some nursery stock. In the following decades, about 3.5 billion chestnut trees were killed. Although small groups of trees may have escaped, the vast majority of this species is gone.

Note that this is a disease of the true American chestnut tree which is the species, Castanea dentata. These are the ones that produced the nuts from the song, "Chestnuts roasting in an open fire...".

These are NOT the common horsechestnut which is the species Aesculus hippocastanum. The fruit of this common tree are actually poisonous.

Chestnut blight is what is called a canker disease. A canker is like an open wound that kills the cambium layer just beneath the bark. If the canker expands all the way around a stem or trunk, it will kill the stem or the entire tree.

For many decades, plant breeders at a number of universities have been trying to find a strain of American chestnut that is resistant to this disease. This is an extremely long process since the plants must be grown from seeds. Progress is being made but to date, there is no evidence of a truly resistant American chestnut available.

 

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

Along with the American tree, the European chestnut, Castenae sativa, is also very susceptible to the disease. The Chinese chestnut, C. mollissima and the Japanese chestnut, C.crenata, are resistant but their nuts, while nice, are not the same as the American chestnut.

 

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