A MEMBER: What preparation of Bordeaux mixture do you use, Dr. Morris?
DR. MORRIS: I use a commercial preparation called Pyrox.
MR. CARL J. POLL: Will the chestnut blight attack any other trees besides the chestnut?
DR. METCALF: Outside of the chestnut genus, that is, the genus Castanea, the disease goes on to a few other trees. A curious fact is that it will go on to the sweet gum, a tree not related at all, and it will go on to a few oaks, in no case enough to seriously damage them as it does the chestnuts, but enough so that those trees can easily be carriers of the disease.
THE PRESIDENT: I think we might pass from this funeral. We have a paper by Dr. Van Fleet, whose work, I suppose, is known to everybody here. The paper has been prepared by Dr. Van Fleet and will be read by the Secretary.
HYBRIDS AND OTHER NEW CHESTNUTS FOR BLIGHT DISTRICTS.
DR. WALTER VAN FLEET, WASHINGTON, D. C.
The sinister spread of chestnut blight, as the bark disease caused by the fungus Endothia parasitica is popularly called, within little more than 10 years, from its place of apparent origin near New York City into 13 states, practically reaching the eastern and northern limits of our native chestnut stands, and sparing in its course no individual trees exposed to infection, has about convinced even the most optimistic observers that without the intervention of natural checks the American chestnut as a forest asset will soon pass away. There is no present indication of diminution in the virulence of the fungus parasite and little reason to hope its progress as a timber destroyer can be stayed by any agency in the control of man. Already the losses, direct and indirect, occasioned by chestnut blight are computed as high as $50,000,000, about half of the estimated value of the entire stand.
With the very reasonable assumption that our native chestnut is doomed to virtual extinction it is well to consider in time if it can be replaced as a timber and nut-producing tree by other chestnut species or combinations of species less subject to injury by this disease-producing organism. The Endothia fungus, as a destructive parasite, is apparently confined to the chestnut, rarely if ever harmfully affecting genera even as closely allied as the oak (Quercus) or Castanopsis. Of the various species of chestnut or Castanea those native to Japan and Central China appear most resistant, probably having been for ages accustomed to the presence of the fungus, while the European chestnut, Castanea sativa, our native C. Americana, and our chinquapin, fall easy victims when exposed to infection. Of the Asiatic forms Castanea crenata of Japan and Eastern China and C. molissima of the interior are most promising in this respect, though the latter is still an almost unknown quantity as regards cultivation in this country.
Castanea crenata, commonly known as Japan chestnut, in its more typical forms is highly resistant, so seldom showing material injury that, for practical purposes, it may be regarded as immune. Japan chestnut seedlings raised from nuts grown in proximity to our native chestnut and exposed to the influence of its pollen are at times more seriously affected, but are rarely destroyed by the bark disease. The Japan chestnut is of comparatively low growth, of small value for timber purposes, but as a nut-producer is very fruitful and precocious, bearing great crops at an early age. The nuts are often very large but usually of poor quality. The species, however, proves quite plastic in the hands of the plant breeder, being readily modified in the directions most desired by the ordinary methods of cross-pollination and selection. It freely hybridizes with all other chestnut species and varieties that have been tried, and forms the basis of the most hopeful work in breeding for disease-resistance that has yet been attempted.