By Sandra L. Anagnostakis, The Connecticut Agricultural Experiment Station, Box 1106, New Haven, CT 06504, phone 203-974-8498, fax 203-974-8502
American chestnut trees were once a major part of our North-Eastern forests. In the 1880's a
fungus came into the U.S. on imported Japanese chestnut trees. It infected through wounds and
quickly spread, killing our native chestnuts and chinquapins.
Even though this chestnut blight fungus kills stems, the trees usually sprout
from the base forming a clump of sprouts which become wounded, infected, die,
and sprout again.
The Connecticut Agricultural Experiment Station has been working on this
problem since the beginning of the epidemic, planting resistant Asian chestnut
species and crossing them with susceptible American trees. We now have the
finest collection of species and hybrids of chestnut trees in the world.
In 1972 we imported from Italy a biological control, which is a virus that keeps
the blight fungus from killing chestnut trees. The virus-infected strains have
less pigment when grown in the lab, and produce swollen cankers on the bark
instead of the lethal, sunken cankers. These swollen cankers have healthy
tissue underneath them.
This biological control works well in orchards, keeping even very susceptible,
American chestnut trees alive, and allowing the breeding work to continue. It
works less well in the forest, where many other trees are competing for the light,
nutrients, and moisture.
We have some new virus-infected strains of the fungus which have been
improved using molecular biology, and these are being tested in the Housatonic
State Forest in Sharon, CT.
We are proceeding with the double approach of improving the biological
control of chestnut blight disease and breeding better, more disease resistant trees
for forests and for orchards.
Chestnuts
An Historical Reference for Chestnut Introductions Into North America
Chestnuts And The Introduction Of Chestnut Blight
Oriental Chestnut Gall Wasp Found On American Chestnut Trees
Valuable Chestnut Germplasm In Connecticut
Chestnut Breeding In The United States
Sources Of Chestnut Trees 1998
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