How Does the Chestnut Blight Affect the Tree?
Infection of this disease occurs through openings, from wounds, in the bark of twigs. The fungus then grows into through the bark and works its way into the water and food conducting tissues. Infections normally begin on young twigs. Where growth of the fungus occurs, cankers or dead areas form around the circumference of the twigs, preventing water and minerals, from being transported to all parts of the tree, above the canker. Infections occur from twig to twig and death occurs rapidly in these terminal branches and when the infection reaches the main trunk, death of the entire tree will follow. Unlike the crop plants which we have discussed, superficial spraying with a fungicide is useless, since the infection occurs deep within the tree, below the bark. In theory, the disease can be controlled in a single tree or perhaps a small number of trees, if all the infected twigs are pruned and destroyed while the infection is just beginning. However, with the millions of trees that that we
