The Chairman: The subject of the next paper is Some Problems in the Treatment of the Chestnut. It will be presented by Mr. Pierce, after which we will have a general discussion of the entire subject. Mr. Pierce: Mr. President, ladies and gentlemen: I see that, as we wrote our papers separately, some of the things I had in mind will be similar to those Mr. Rockey had. SOME PROBLEMS IN THE TREATMENT OF DISEASED CHESTNUT TREES BY ROY G. PIERCE Tree Surgeon, Pennsylvania Chestnut Tree Blight Commission The problems that present themselves to the growers of chestnut trees concerning the present disease may be summed up under three heads: first, what the disease is, how it is caused, and how it may be recognized; second, what is to be done with diseased trees to bring them to health or to prevent them from infecting other healthy trees nearby; third, what means in the future can be undertaken to keep a tree healthy, that is, to prevent reinfection. First, what the disease is, how it is caused, and how it may be recognized. The disease known as the chestnut tree blight is caused by the fungus, _Diaporthe parasitica_, which usually finds entrance to the tree through wounds in the bark. The mycelium or mass of fungous filaments gradually spreads through the bark in much the same manner as mold spreads over and through a piece of bread, even penetrating the wood to a depth of sometimes five annual rings. The spread of the fungus, resulting in the cutting off of the sap flow, is the immediate cause of the wilting and dying of the leaves and branch above the point of girdling. This wilting of the leaves, followed later by the death of one branch after another as the fungus spreads, has given rise to the term "blight" of the chestnut trees. The danger signals which the chestnut tree displays when diseased are not a few. In summer, when the tree is first affected, the leaves turn yellow-green and wilt, later turning brown. Small burs and withered leaves retained in winter are some signs of the diseased condition of the tree. At the base of the blighted part a lesion, or reddish brown canker, is usually found. This lesion may be a sunken area or, as is frequently the case, a greatly enlarged swelling, known as a hypertrophy. After a branch has become completely girdled sprouts or suckers are very apt to be found below the point of girdling. In old furrowed bark on the main trunk of the tree the presence of the disease is seen in the reddish brown spore-bearing pustules in the fissures. In determining the presence of the fungus in the furrowed bark of old trees, one must learn to recognize the difference between the light brown color characteristic of fissures in healthy growing bark, and the reddish brown color of the fungus. When the disease has been present several years the bark completely rots and shrinks away from the wood, and when the bark is struck with an axe a hollow sound is produced.