Fruit Trees and Vines - The MiniFarming - page 130

distinctive infection be completely removed from the tree and
destroyed by incineration.

Most nut trees never show signs of disease, and the regular
spraying required for fruit trees is not needed in most cases.
Major nut tree diseases include chestnut blight, pecan scab,
walnut anthracnose, and walnut blight.

Chestnut blight was introduced into the United States before
1900 through the importation of various Asian chestnut
species that carry the causative fungus but are resistant to it
themselves. The American chestnut, native to Eastern North
America, has no resistance to this fungus; within a generation
this majestic tree, soaring up to 100 feet and measuring up to
10 feet across, was reduced to little more than a shrub that
struggles a few years before succumbing to the threat. To put
the impact of chestnut blight into perspective, it is estimated
that in 1900, 25% of all the trees in the Appalachians were
American chestnuts.

There are four ways of dealing with chestnut blight: prompt
removal of infected branches, treatment of cankers in existing
trees for five years with injections of a hypovirulent strain of
the fungus, planting resistant Asian chestnut varieties, and
planting American varieties that have incorporated
disease-resistant genes through repetitive backcrossing and
selection to maximize native DNA content while retaining
resistance genes. 39

Mini-farmers interested in growing and preserving American
chestnuts should seek guidance (and seeds!) from the
American Chestnut Cooperators' Foundation